Journal articles on the topic 'Secretory (E/S) proteins'
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Vicente, R. L., S. Marín, J. R. Valverde, C. Palomino, R. P. Mellado, and S. Gullón. "Functional identification of a Streptomyces lividans FKBP-like protein involved in the folding of overproduced secreted proteins." Open Biology 9, no. 10 (October 2019): 190201. http://dx.doi.org/10.1098/rsob.190201.
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Some bacterial peptidyl-prolyl cis/trans isomerases (PPIases) are involved in secretory protein folding after the translocation step. Streptomyces lividans has been used as a host for engineering extracellular overproduction of homologous and heterologous proteins in industrial applications. Although the mechanisms governing the major secretory pathway (Sec route) and the minor secretory pathway (Tat route) are reasonably well described, the function of proteins responsible for the extracellular secretory protein folding is not characterized as yet. We have characterized a Tat-dependent S . lividans FK506-binding protein-like lipoprotein (FKBP) that has PPIase activity. A mutant in the sli-fkbp gene induces a secretion stress response and affects secretion and activity of the Sec-dependent protein α-amylase. Additionally, propagation in high copy number of the sli-fkbp gene has a positive effect on the activity of both the overproduced α-amylase and the overproduced Tat-dependent agarase, both containing proline cis isomers. Targeted proteomic analyses showed that a relevant group of secreted proteins in S. lividans TK21 are affected by Sli-FKBP, revealing a wide substrate range. The results obtained indicate that, regardless of the secretory route used by proteins in S. lividans , adjusting the expression of sli-fkbp may facilitate folding of dependent proteins when engineering Streptomyces strains for the overproduction of homologous or heterologous secretory proteins.
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Bickel, Perry E., Philipp E. Scherer, and Harvey F. Lodish. "P-4: Identification and cloning of adipocyte-specific secretory proteins." Experimental and Clinical Endocrinology & Diabetes 104, S 02 (July 15, 2009): 68. http://dx.doi.org/10.1055/s-0029-1211547.
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Albers, Sonja-Verena, Zalán Szabó, and Arnold J. M. Driessen. "Archaeal Homolog of Bacterial Type IV Prepilin Signal Peptidases with Broad Substrate Specificity." Journal of Bacteriology 185, no. 13 (July 1, 2003): 3918–25. http://dx.doi.org/10.1128/jb.185.13.3918-3925.2003.
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ABSTRACT A large number of secretory proteins in the thermoacidophile Sulfolobus solfataricus are synthesized as a precursor with an unusual leader peptide that resembles bacterial type IV prepilin signal sequences. This set of proteins includes the flagellin subunit but also various solute binding proteins. Here we describe the identification of the S. solfataricus homolog of bacterial type IV prepilin peptidases, termed PibD. PibD is an integral membrane protein that is phylogenetically related to the bacterial enzymes. When heterologously expressed in Escherichia coli, PibD is capable of processing both the flagellin and glucose-binding protein (GlcS) precursors. Site-directed mutagenesis of the GlcS signal peptide shows that the substrate specificity of PibD is consistent with the variations found in proteins with type IV prepilin-like signal sequences of S. solfataricus. We conclude that PibD is responsible for the processing of these secretory proteins in S. solfataricus.
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Markwardt, Michele L., Andongfac Nkobena, Shi-Ying Ding, and Mark A. Rizzo. "Association with Nitric Oxide Synthase on Insulin Secretory Granules Regulates Glucokinase Protein Levels." Molecular Endocrinology 26, no. 9 (September 1, 2012): 1617–29. http://dx.doi.org/10.1210/me.2012-1183.
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Abstract Glucokinase (GCK) association with insulin-secretory granules is controlled by interaction with nitric oxide synthase (NOS) and is reversed by GCK S-nitrosylation. Nonetheless, the function of GCK sequestration on secretory granules is unknown. Here we report that the S-nitrosylation blocking V367M mutation prevents GCK accumulation on secretory granules by inhibiting association with NOS. Expression of this mutant is reduced compared with a second S-nitrosylation blocking GCK mutant (C371S) that accumulates to secretory granules and is expressed at levels greater than wild type. Even so, the rate of degradation for wild type and mutant GCK proteins were not significantly different from one another, and neither mutation disrupted the ability of GCK to be ubiquitinated. Furthermore, gene silencing of NOS reduced endogenous GCK content but did not affect β-actin content. Treatment of GCK(C371S) expressing cells with short interfering RNA specific for NOS also blocked accumulation of this protein to secretory granules and reduced expression levels to that of GCK(V367M). Conversely, cotransfection of catalytically inactive NOS increased GCK-mCherry levels. Expression of GCK(C371S) in βTC3 cells enhanced glucose metabolism compared with untransfected cells and cells expressing wild type GCK, even though this mutant has slightly reduced enzymatic activity in vitro. Finally, molecular dynamics simulations revealed that V367M induces conformational changes in GCK that are similar to S-nitrosylated GCK, thereby suggesting a mechanism for V367M-inhibition of NOS association. Our findings suggest that sequestration of GCK on secretory granules regulates cellular GCK protein content, and thus cellular GCK activity, by acting as a storage pool for GCK proteins.
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Gorr, Sven-Ulrik, Xue Fen Huang, Darrin J. Cowley, Regina Kuliawat, and Peter Arvan. "Disruption of disulfide bonds exhibits differential effects on trafficking of regulated secretory proteins." American Journal of Physiology-Cell Physiology 277, no. 1 (July 1, 1999): C121—C131. http://dx.doi.org/10.1152/ajpcell.1999.277.1.c121.
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For several secretory proteins, it has been hypothesized that disulfide-bonded loop structures are required for sorting to secretory granules. To explore this hypothesis, we employed dithiothreitol (DTT) treatment in live pancreatic islets, as well as in PC-12 and GH4C1cells. In islets, disulfide reduction in the distal secretory pathway did not increase constitutive or constitutive-like secretion of proinsulin (or insulin). In PC-12 cells, DTT treatment caused a dramatic increase in unstimulated secretion of newly synthesized chromogranin B (CgB), presumably as a consequence of reducing the single conserved chromogranin disulfide bond (E. Chanat, U. Weiss, W. B. Huttner, and S. A. Tooze. EMBO J.12: 2159–2168, 1993). However, in GH4C1cells that also synthesize CgB endogenously, DTT treatment reduced newly synthesized prolactin and blocked its export, whereas newly synthesized CgB was routed normally to secretory granules. Moreover, on transient expression in GH4C1cells, CgA and a CgA mutant lacking the conserved disulfide bond showed comparable multimeric aggregation properties and targeting to secretory granules, as measured by stimulated secretion assays. Thus the conformational perturbation of regulated secretory proteins caused by disulfide disruption leads to consequences in protein trafficking that are both protein and cell type dependent.
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Kochanowski, Maciej, Joanna Dąbrowska, Mirosław Różycki, Jacek Sroka, Jacek Karamon, Aneta Bełcik, Weronika Korpysa-Dzirba, and Tomasz Cencek. "Proteomic Profiling and In Silico Characterization of the Secretome of Anisakis simplex Sensu Stricto L3 Larvae." Pathogens 11, no. 2 (February 14, 2022): 246. http://dx.doi.org/10.3390/pathogens11020246.
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Anisakis simplex sensu stricto (s.s.) L3 larvae are one of the major etiological factors of human anisakiasis, which is one of the most important foodborne parasitic diseases. Nevertheless, to date, Anisakis secretome proteins, with important functions in nematode pathogenicity and host-parasite interactions, have not been extensively explored. Therefore, the aim of this study was to identify and characterize the excretory-secretory (ES) proteins of A. simplex L3 larvae. ES proteins of A. simplex were subjected to liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis, and the identified proteins were then analyzed using bioinformatics tools. A total of 158 proteins were detected. Detailed bioinformatic characterization of ES proteins was performed, including Gene Ontology (GO) analysis, identification of enzymes, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways analysis, protein family classification, secretory pathway prediction, and detection of essential proteins. Furthermore, of all detected ES proteins, 1 was identified as an allergen, which was Ani s 4, and 18 were potential allergens, most of which were homologs of nematode and arthropod allergens. Nine potential pathogenicity-related proteins were predicted, which were predominantly homologs of chaperones. In addition, predicted host-parasite interactions between the Anisakis ES proteins and both human and fish proteins were identified. In conclusion, this study represents the first global analysis of Anisakis ES proteins. The findings provide a better understanding of survival and invasion strategies of A. simplex L3 larvae.
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Tan, A., J. Bolscher, C. Feltkamp, and H. Ploegh. "Retrograde transport from the Golgi region to the endoplasmic reticulum is sensitive to GTP gamma S." Journal of Cell Biology 116, no. 6 (March 15, 1992): 1357–67. http://dx.doi.org/10.1083/jcb.116.6.1357.
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The involvement of GTP-binding proteins in the intracellular transport of the secretory glycoprotein alpha 1-antitrypsin was investigated in streptolysin O-permeabilized HepG2 cells. This permeabilization procedure allows ready access to the intracellular milieu of the membrane-impermeant, nonhydrolyzable GTP analog GTP gamma S. In streptolysin O-permeabilized HepG2 cells, the constitutive secretory pathway remains functional and is sensitive to GTP gamma S. Exposure of HepG2 cells to brefeldin A resulted in redistribution of Golgi-resident glycosyltransferases (including both alpha 2----3 and alpha 2----6 sialyltransferases) to the ER. This redistribution was sensitive to GTP gamma S. Our results suggest that GTP-binding proteins are involved in the regulation not only of the anterograde, but also of the retrograde, pathway.
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Blázquez, Mercedes, and Kathleen I. Shennan. "Basic mechanisms of secretion: sorting into the regulated secretory pathway." Biochemistry and Cell Biology 78, no. 3 (April 2, 2000): 181–91. http://dx.doi.org/10.1139/o00-010.
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Targeting proteins to their correct cellular location is crucial for their biological function. In neuroendocrine cells, proteins can be secreted by either the constitutive or the regulated secretory pathways but the mechanism(s) whereby proteins are sorted into either pathway is unclear. In this review we discuss the possibility that sorting is either an active process occurring at the level of the trans-Golgi network, or that sorting occurs passively in the immature granules. The possible involvement of protein-lipid interactions in the sorting process is also raised. Key words: lipid rafts, regulated secretory pathway, secretion, sorting receptors, sorting signals, trans-Golgi network.
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Donovan, Kirk W., and Anthony Bretscher. "Tracking individual secretory vesicles during exocytosis reveals an ordered and regulated process." Journal of Cell Biology 210, no. 2 (July 13, 2015): 181–89. http://dx.doi.org/10.1083/jcb.201501118.
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Post-Golgi secretory vesicle trafficking is a coordinated process, with transport and regulatory mechanisms to ensure appropriate exocytosis. While the contributions of many individual regulatory proteins to this process are well studied, the timing and dependencies of events have not been defined. Here we track individual secretory vesicles and associated proteins in vivo during tethering and fusion in budding yeast. Secretory vesicles tether to the plasma membrane very reproducibly for ∼18 s, which is extended in cells defective for membrane fusion and significantly lengthened and more variable when GTP hydrolysis of the exocytic Rab is delayed. Further, the myosin-V Myo2p regulates the tethering time in a mechanism unrelated to its interaction with exocyst component Sec15p. Two-color imaging of tethered vesicles with Myo2p, the GEF Sec2p, and several exocyst components allowed us to document a timeline for yeast exocytosis in which Myo2p leaves 4 s before fusion, whereas Sec2p and all the components of the exocyst disperse coincident with fusion.
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High, S., S. S. Andersen, D. Görlich, E. Hartmann, S. Prehn, T. A. Rapoport, and B. Dobberstein. "Sec61p is adjacent to nascent type I and type II signal-anchor proteins during their membrane insertion." Journal of Cell Biology 121, no. 4 (May 15, 1993): 743–50. http://dx.doi.org/10.1083/jcb.121.4.743.
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We have identified membrane components which are adjacent to type I and type II signal-anchor proteins during their insertion into the membrane of the ER. Using two different cross-linking approaches a 37-38-kD nonglycosylated protein, previously identified as P37 (High, S., D. Görlich, M. Wiedmann, T. A. Rapoport, and B. Dobberstein. 1991. J. Cell Biol. 113:35-44), was found adjacent to all the membrane inserted nascent chains used in this study. On the basis of immunoprecipitation, this ER protein was shown to be identical to the recently identified mammalian Sec61 protein. Thus, Sec61p is the principal cross-linking partner of both type I and type II signal-anchor proteins during their membrane insertion (this work), and of secretory proteins during their translocation (Görlich, D., S. Prehn, E. Hartmann, K.-U. Kalies, and T. A. Rapoport. 1992. Cell. 71:489-503). We propose that membrane proteins of both orientations, and secretory proteins employ the same ER translocation sites, and that Sec61p is a core component of these sites.
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Chaffin, W. LaJean. "Candida albicans Cell Wall Proteins." Microbiology and Molecular Biology Reviews 72, no. 3 (September 2008): 495–544. http://dx.doi.org/10.1128/mmbr.00032-07.
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SUMMARY The Candida albicans cell wall maintains the structural integrity of the organism in addtion to providing a physical contact interface with the environment. The major components of the cell wall are fibrillar polysaccharides and proteins. The proteins of the cell wall are the focus of this review. Three classes of proteins are present in the candidal cell wall. One group of proteins attach to the cell wall via a glycophosphatidylinositol remnant or by an alkali-labile linkage. A second group of proteins with N-terminal signal sequences but no covalent attachment sequences are secreted by the classical secretory pathway. These proteins may end up in the cell wall or in the extracellular space. The third group of proteins lack a secretory signal, and the pathway(s) by which they become associated with the surface is unknown. Potential constituents of the first two classes have been predicted from analysis of genome sequences. Experimental analyses have identified members of all three classes. Some members of each class selected for consideration of confirmed or proposed function, phenotypic analysis of a mutant, and regulation by growth conditions and transcription factors are discussed in more detail.
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Ghyselinck, N. B., C. Jimenez, Y. Courty, and J. P. Dufaure. "Androgen-dependent messenger RNA(s) related to secretory proteins in the mouse epididymis." Reproduction 85, no. 2 (March 1, 1989): 631–39. http://dx.doi.org/10.1530/jrf.0.0850631.
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Ewenstein, Bruce, and Yvonne Datta. "Regulated Secretion in Endothelial Cells: Biology and Clinical Implications." Thrombosis and Haemostasis 86, no. 11 (2001): 1148–55. http://dx.doi.org/10.1055/s-0037-1616043.
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SummaryRegulated secretion provides a means by which endothelial cells (EC) can rapidly and selectively alter the microenvironment of individual vascular beds, and modulate the interrelated processes of coagulation, fibrinolysis, and inflammation. The rapid release of high molecular weight multimers of von Willebrand factor (VWF) and surface expression of P-selectin in response to a wide variety of stimuli have been well documented, and are the result of exocytosis of Weibel-Palade bodies (WPB). The regulated release of other EC secretory proteins, including tissue plasminogen activator (tPA), interleukin-8, endothelin-1, and multimerin, has also been described. New light is being shed on how secretory proteins are selectively targeted to storage granules in EC, and on the molecular and cellular events that comprise regulated secretion. Knowledge of the mechanisms of sorting and secretion from EC storage granules may provide basis for new strategies for treating inflammatory and coagulation disorders.
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Matsuno, Yuta, Yahia A. Amin, Kazuya Kusama, and Kazuhiko Imakawa. "Formation of fibrin at sites of conceptus adhesion in the ewe." Reproduction 161, no. 6 (June 1, 2021): 709–20. http://dx.doi.org/10.1530/rep-20-0531.
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In ruminants, various molecules are involved in regulating conceptus attachment and adhesion; however, molecules that maintain the conceptus adhesion have not been well characterized. We hypothesized that conceptus must produce a molecule(s), yet uncharacterized or overlooked, which maintain conceptus adhesion to the uterine epithelium. In this study, we aimed to identify new candidate(s) in conceptus secretory proteins responsible for maintaining conceptus adhesion in sheep. We performed RNA-sequence analysis with ovine conceptuses, followed by endometria obtained from pregnant animals on day 15 (P15: pre-attachment), 17 (P17: right after attachment), and 21 (P21: post-attachment; adhesion) and iTRAQ analysis of uterine flushing on P15 and P17. To identify the proteins secreted from conceptuses, we cross-referenced the transcriptome and proteome data. These analyses identified 16 and 26 proteins as conceptus secretory proteins on P15 and P17, respectively. Gene ontology analysis revealed that the conceptus secretory proteins were enriched in those categorized to fibrinolysis and coagulation. RT-qPCR analysis verified that the expression levels of transcripts in conceptuses encoding coagulation factors, fibrinogen subunits, and fibrinolysis factors were significantly higher on P21 than on P15 or P17, which were supported by those through in situ hybridization, Western blotting and immunohistochemistry. Histology analysis confirmed that fibrin protein was present at the conceptus adhesion region on P21. These results suggest that in addition to the numerous adhesion molecules so far characterized, fibrin is a new candidate molecule for maintaining conceptus adhesion for pregnancy continuation in ruminants.
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Rizzo, Mark A., and David W. Piston. "Regulation of β cell glucokinase by S-nitrosylation and association with nitric oxide synthase." Journal of Cell Biology 161, no. 2 (April 21, 2003): 243–48. http://dx.doi.org/10.1083/jcb.200301063.
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Glucokinase (GK) activity plays a key role in glucose-stimulated insulin secretion from pancreatic β cells. Insulin regulates GK activity by modulating its association with secretory granules, although little is known about the mechanisms involved in regulating this association. Using quantitative imaging of multicolor fluorescent proteins fused to GK, we found that the dynamic association of GK with secretory granules is modulated through nitric oxide (NO). Our results in cultured β cells show that insulin stimulates NO production and leads to S-nitrosylation of GK. Furthermore, inhibition of NO synthase (NOS) activity blocks insulin-stimulated changes in both GK association with secretory granules and GK conformation. Mutation of cysteine 371 to serine blocks S-nitrosylation of GK and causes GK to remain tightly bound to secretory granules. GK was also found to interact stably with neuronal NOS as detected by coimmunoprecipitation and fluorescence resonance energy transfer. Finally, attachment of a nuclear localization signal sequence to NOS drives GK to the nucleus in addition to its normal cytoplasmic and granule targeting. Together, these data suggest that the regulation of GK localization and activity in pancreatic β cells is directly related to NO production and that the association of GK with secretory granules occurs through its interaction with NOS.
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Meng, Zhen, Maria C. Edman, Pang-Yu Hsueh, Chiao-Yu Chen, Wannita Klinngam, Tanya Tolmachova, Curtis T. Okamoto, and Sarah F. Hamm-Alvarez. "Imbalanced Rab3D versus Rab27 increases cathepsin S secretion from lacrimal acini in a mouse model of Sjögren's Syndrome." American Journal of Physiology-Cell Physiology 310, no. 11 (June 1, 2016): C942—C954. http://dx.doi.org/10.1152/ajpcell.00275.2015.
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The mechanism responsible for the altered spectrum of tear proteins secreted by lacrimal gland acinar cells (LGAC) in patients with Sjögren's Syndrome (SS) remains unknown. We have previously identified increased cathepsin S (CTSS) activity as a unique characteristic of tears of patients with SS. Here, we investigated the role of Rab3D, Rab27a, and Rab27b proteins in the enhanced release of CTSS from LGAC. Similar to patients with SS and to the male nonobese diabetic (NOD) mouse model of SS, CTSS activity was elevated in tears of mice lacking Rab3D. Findings of lower gene expression and altered localization of Rab3D in NOD LGAC reinforce a role for Rab3D in suppressing excess CTSS release under physiological conditions. However, CTSS activity was significantly reduced in tears of mice lacking Rab27 isoforms. The reliance of CTSS secretion on Rab27 activity was supported by in vitro findings that newly synthesized CTSS was detected in and secreted from Rab27-enriched secretory vesicles and that expression of dominant negative Rab27b reduced carbachol-stimulated secretion of CTSS in cultured LGAC. High-resolution 3D-structured illumination microscopy revealed microdomains of Rab3D and Rab27 isoforms on the same secretory vesicles but present in different proportions on different vesicles, suggesting that changes in their relative association with secretory vesicles may tailor the vesicle contents. We propose that a loss of Rab3D from secretory vesicles, leading to disproportionate Rab27-to-Rab3D activity, may contribute to the enhanced release of CTSS in tears of patients with SS.
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Grimes, M., and R. B. Kelly. "Intermediates in the constitutive and regulated secretory pathways released in vitro from semi-intact cells." Journal of Cell Biology 117, no. 3 (May 1, 1992): 539–49. http://dx.doi.org/10.1083/jcb.117.3.539.
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Regulated secretory cells have two pathways that transport secreted proteins from the Golgi complex to the cell surface. To identify carrier vesicles involved in regulated and constitutive secretion, PC12 pheochromocytoma cells were labeled with [35S]sulfate to identify markers for the two secretory pathways, then mechanically permeabilized and incubated in vitro. Small constitutive secretory vesicles, containing mostly sulfated proteoglycans, accumulated during an in vitro incubation with ATP. In the presence of GTP gamma S, the constitutive vesicles became significantly more dense, suggesting that a coated intermediate was stabilized. Larger immature regulated secretory granules, enriched in sulfated secretogranin II, also escaped from the permeabilized cells in vitro. During granule maturation, their density increased and the amount of cofractionating proteoglycans diminished. The data suggest that sorting continues during secretory granule maturation.
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Miura, Natsuko, Aya Kirino, Satoshi Endo, Hironobu Morisaka, Kouichi Kuroda, Masahiro Takagi, and Mitsuyoshi Ueda. "Tracing Putative Trafficking of the Glycolytic Enzyme Enolase via SNARE-Driven Unconventional Secretion." Eukaryotic Cell 11, no. 8 (June 29, 2012): 1075–82. http://dx.doi.org/10.1128/ec.00075-12.
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ABSTRACT Glycolytic enzymes are cytosolic proteins, but they also play important extracellular roles in cell-cell communication and infection. We used Saccharomyces cerevisiae to analyze the secretory pathway of some of these enzymes, including enolase, phosphoglucose isomerase, triose phosphate isomerase, and fructose 1,6-bisphosphate aldolase. Enolase, phosphoglucose isomerase, and an N-terminal 28-amino-acid-long fragment of enolase were secreted in a sec23 -independent manner. The enhanced green fluorescent protein (EGFP)-conjugated enolase fragment formed cellular foci, some of which were found at the cell periphery. Therefore, we speculated that an overview of the secretory pathway could be gained by investigating the colocalization of the enolase fragment with intracellular proteins. The DsRed-conjugated enolase fragment colocalized with membrane proteins at the cis -Golgi complex, nucleus, endosome, and plasma membrane, but not the mitochondria. In addition, the secretion of full-length enolase was inhibited in a knockout mutant of the intracellular SNARE protein-coding gene TLG2 . Our results suggest that enolase is secreted via a SNARE-dependent secretory pathway in S. cerevisiae .
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CERVI, L., G. ROSSI, and D. T. MASIH. "Potential role for excretory–secretory forms of glutathione-S-transferase (GST) in Fasciola hepatica." Parasitology 119, no. 6 (December 1999): 627–33. http://dx.doi.org/10.1017/s003118209900517x.
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The excretory–secretory antigen of Fasciola hepatica (ESA) is involved in the suppressive phenomena of cellular immune responses in rats. The ESA can depress the proliferative response of spleen mononuclear cells and inhibit nitric oxide (NO) production by peritoneal cells. In the present study we identified ESA proteins of ca 24 kDa, which shared significant sequence homology to glutathione-S-transferase (GST) obtained from homogenates of F. hepatica adults, other helminths and different mammals. When the dimeric form of these proteins ca 48 kDa was cultured with rat spleen cells, a significant decrease of proliferative response to Con A was detected, starting from 20 μg/ml of ESA protein (P<0·03). We also observed a significant inhibition of nitrite production by incubation with the dimeric form in normal peritoneal macrophages (P<0·04). These results indicated that the GST secreted by the parasite could be involved in evasion of the parasite from the host immune response.
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Villalón, Manuel, Dale E. Johnson, and Pedro Verdugo. "X-ray microanalysis of calcium content in secretory granules of goblet cell of the rabbit oviduct." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 2 (August 12, 1990): 178–79. http://dx.doi.org/10.1017/s042482010013448x.
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Secretory granules have two ubiquitous features: they are acidic, and they contain a distinct combination of a two countercharged species: a polyanion, which is usually interconnected forming a polymer network, and a cation or polycation. In most endocrine cells the polyanion belongs to the chromogranin/secretogranin family of acidic proteins, while the polycation is usually the hormonal or transmitter species itself (amines, regulatory peptides, hormones), or else a metallic cation (Ca++, K+, Mg++)(Ann. Rev. Physiol 52:625,1990). In exocrine secretion, like in serous cells, the polyanic polymer network is made of proteoglycans and the shielding cations are a family of polycationic proteins that include lysozyme, lactoferrin, and antileucoprotease (Ann. Rev. Physiol. 52:97,1990). We have proposed that the role of cations or polycations in the granule is to facilitate the condensation of secretory products by screening the polyanionic charges of the secretory networks (Ann. Rev. Physiol. 52:157,1990). In goblet cells of the oviduct, the polyanionic polymers are mucins, while the correponding cationic species has not been identified. In this study x-ray microanalysis was used to determine the presence of a shielding cation(s) in secretory granules of goblet cells of the rabbit oviduct.
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Arber, S., K. H. Krause, and P. Caroni. "s-cyclophilin is retained intracellularly via a unique COOH-terminal sequence and colocalizes with the calcium storage protein calreticulin." Journal of Cell Biology 116, no. 1 (January 1, 1992): 113–25. http://dx.doi.org/10.1083/jcb.116.1.113.
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Cyclophilins (cyclosporin A-binding proteins) are conserved, ubiquitous, and abundant proteins that accelerate the isomerization of XaaPro peptide bonds and the refolding of proteins in vitro. s-Cyclophilin is a member of the cyclophilin family with unique NH2- and COOH-terminal extensions, and with a signal sequence. We now report that s-cyclophilin is retained in the cell, and that the conserved s-cyclophilin-specific COOH-terminal extension VEKPFAIAKE is sufficient to direct a secretory protein to s-cyclophilin containing structures. Antibodies to s-cyclophilin-specific peptides were produced and the location of the protein was determined by an immunocytochemical study at the light microscopic level. s-Cyclophilin colocalized with the Ca(2+)-binding protein calreticulin and, to a lesser extent, with the microsomal Ca(2+)-ATPase in the myogenic cell line L6, and with the Ca(2+)-binding protein calsequestrin in skeletal muscle. In activated platelets, s-cyclophilin immunoreactivity was detected in a ring-like structure that might correspond to the Ca(2+)-storing and -releasing dense tubular network. In spreading cells, s-cyclophilin containing vesicular structures accumulated at actin-rich protrusion sites. While s-cyclophilin consistently codistributed with Ca2+ storage site markers, the distribution of s-cyclophilin immunoreactivity was not identical to that of ER markers. To determine whether the COOH-terminal extension of s-cyclophilin was involved in its intracellular transport we added this sequence to the COOH-terminus of the secretory protein glia-derived nexin. Appropriate constructs were expressed transiently in cultured cells and proteins were detected with specific antibodies. We found that glia-derived nexin with the COOH-terminal sequence VEKPFAIAKE (but not with the control sequence GLVVMNIT) colocalized with endogenous s-cyclophilin, indicating that the sequence contained retention information. These results indicate that s-cyclophilin is a retained component of an intracellular organelle and that it may accumulate in specialized portions of the ER, and possibly in calciosomes. Because of its conserved structure, widespread distribution, and abundance s-cyclophilin may be a useful marker to study the biogenesis and distribution of ER subcompartments.
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Bachhawat, A. K., and S. Pillai. "Distinct intracellular fates of membrane and secretory immunoglobulin heavy chains in a pre-B cell line." Journal of Cell Biology 115, no. 3 (November 1, 1991): 619–24. http://dx.doi.org/10.1083/jcb.115.3.619.
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The intracellular fates of membrane and secretory immunoglobulin heavy chains were examined in a pre-B cell line that has switched to the gamma isotype. The membrane form of the heavy chain (gamma m) was rapidly degraded while the secretory form (gamma s) was retained intracellularly in association with BiP. The degradation of gamma m could not be inhibited by ammonium chloride, chloroquine, or monensin suggesting that it occurred in a nonlysosomal compartment. The inability to detect any Endo H-resistant form of gamma m before its degradation suggested that degradation occurs before entry into the Golgi compartment. Degradation of gamma m could be inhibited by incubation at 24 degrees C. In a derivative of this cell line expressing a transfected kappa gene, gamma s formed disulfide linked tetramers with kappa and was secreted, while gamma m, although associated with kappa, continued to be rapidly degraded. These observations suggest that membrane and secretory heavy chain proteins are retained by distinct intracellular mechanisms. Although masking of the CH1 domain abrogates gamma s retention, this domain does not influence the intracellular fate of gamma m.
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Grimaldi, K. A., J. C. Hutton, and K. Siddle. "Production and characterization of monoclonal antibodies to insulin secretory granule membranes." Biochemical Journal 245, no. 2 (July 15, 1987): 557–66. http://dx.doi.org/10.1042/bj2450557.
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Monoclonal antibodies to insulin secretory granule membranes were obtained following immunization of mice with granule membranes purified from a rat transplantable insulinoma. The specificities of the antibodies were investigated by using binding assays with different insulinoma subcellular fractions, by indirect immunofluorescence studies with intact and permeabilized cells, and by immunoblotting of granule membrane proteins fractionated by SDS/polyacrylamide-gel electrophoresis. Fifty-six antibodies were characterized initially, and 21 representative cell lines were cloned. The antibodies fell into four categories: (1) binding preferentially to secretory granules, and reacting with a component of approx. 80,000 Da on immunoblots (antigen designated SGM 80); (2) binding preferentially to secretory granules, and reacting with components of approx. 110,000 and 50,000 Da on immunoblots (antigen designated SGM 110); (3) binding preferentially to secretory granules but unreactive on immunoblots; (4) binding to membrane antigen(s) with a widespread intracellular distribution which included granules and plasma membranes. The antigens SGM 80 and SGM 110 were studied in more detail and both were shown to be integral membrane glycoproteins with antigenic determinants located on the internal face of the secretory granule membrane. These antigens were also present in normal rat islets of Langerhans and similar components were detected by immunoblotting in secretory granules from anterior pituitary and adrenal medulla. Proteins which were immunologically related to SGM 80 and SGM 110, but distinct in molecular size, were also identified in liver. It is concluded that secretory granules contain specific components which are restricted in subcellular location but widespread in tissue distribution. The antibodies obtained will be valuable reagents in the further investigation of the biogenesis and turnover of insulin secretory granules.
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Sampaio, Valéria da Silva, Ítalo Antônio Cotta Coutinho, Tiina Särkinen, and Maria Iracema Bezerra Loiola. "Secretory and ecological function of petiolar glands in." Australian Journal of Botany 70, no. 1 (November 23, 2021): 32–41. http://dx.doi.org/10.1071/bt21001.
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Extrafloral nectaries are known from many plant groups but have rarely been recorded in the large genus Solanum or, in fact, in the family Solanaceae. This study set out to explore the functional role of the extrafloral nectaries recently described in Solanum fernandesii, a species endemic to north-eastern Brazil. Light and scanning electron microscopy was used to study the morphoanatomical structure of the nectaries and histochemical analyses were performed to study the chemical composition of the exudates recovered from the glands on the basis of field studies. Light and scanning electron microscopy show that although the petiolar glands in S. fernandesii appear sessile to the naked eye, the glands are short stalked. The epidermis of the glands is composed of short, tightly packed multicellular trichomes. The gland secretions contain a mixture of polysaccharides, pectins, mucilage, proteins, lipids, essential oils, resins, and phenolic compounds on the basis of histochemical tests performed. These findings confirm that the petiolar glands in S. fernandesii are in fact resin glands and not extrafloral nectaries as previously claimed. Our study is the first report of resin glands in the large genus Solanum and we confirm that the glands found in S. fernandesii are unique in the genus.
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Appel, D., and C. Koch-Brandt. "Sorting of a secretory protein (gp80) to the apical surface of Caco-2 cells." Journal of Cell Science 107, no. 2 (February 1, 1994): 553–59. http://dx.doi.org/10.1242/jcs.107.2.553.
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We have investigated the synthesis and polarized secretion of the exogenous gp80 glycoprotein complex in the human epithelial adenocarcinoma cell line, Caco-2. gp80 is secreted at the apical surface of Madin-Darby canine kidney (MDCK) cells and should, therefore, display the signal(s) required for sorting into the apical exocytic pathway. In Caco-2 cells, no bona fide secretory protein released preferentially at the apical surface has been described so far. To address the question of whether Caco-2 cells possess a machinery capable of delivery of secretory proteins at the apical surface, we stably transfected the cells with a recombinant gene coding for the gp80 glycoprotein complex. Pulse-chase analysis showed that stably transfected Caco-2 cells secrete gp80 quantitatively into the medium. In polarized layers of filter-grown Caco-2 cells, the protein was secreted predominantly at the apical surface, demonstrating the ability of the cells to efficiently sort secretory proteins directly into the apical exocytic pathway. Our results further demonstrate that the apical targeting information of gp80 recognized by MDCK cells is also recognized by Caco-2 cells.
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Bazer, FW. "Establishment of pregnancy in sheep and pigs." Reproduction, Fertility and Development 1, no. 3 (1989): 237. http://dx.doi.org/10.1071/rd9890237.
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Sheep conceptuses secrete a protein, ovine trophoblast protein-1 (oTP-1), between days 10 and 21 of gestation, that is responsible for establishment of pregnancy. oTP-1 inhibits uterine production of episodic release of prostaglandin (PG) F2 alpha (PGF) necessary for luteolysis and produced in response to oestradiol and oxytocin. oTP-1 does not compete with oxytocin for binding to its receptors or interfere with oxytocin stimulation of the inositol phospholipid second messenger system after oxytocin receptors are formed. However, oTP-1 may affect synthesis of oxytocin, oestrogen and/or progesterone receptors to alter the ability of the uterus to produce episodic pulses of PGF in response to episodic pulses of oxytocin. Porcine conceptuses secrete oestrogens between days 10 and 15 of pregnancy that are essential for establishment of pregnancy. Oestrogens, directly or indirectly, alter secretion of PGF from an endocrine direction (toward the uterine vasculature) to an exocrine direction (toward the uterine lumen). PGF sequestered in the uterine lumen is unavailable to exert a luteolytic effect on the corpus luteum (CL). Pig conceptus secretory proteins stimulate uterine production of PGF and PGE, but do not appear to be responsible for inhibition of luteolysis. Conceptus secretory proteins of sheep and pigs include proteins that have antiviral activity and are considered interferons. In sheep, oTP-1 has antiluteolytic, immunosuppressive, antiviral and possibly antiproliferative properties. The specific pig conceptus secretory protein(s) possessing antiviral activity has not been established. Unlike oTP-1, however, pig interferon-like protein(s) does not appear to possess antiluteolytic activity.
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Wainwright, Eleanor, and Rebecca K. Shears. "Trichuris WAP and CAP proteins: Potential whipworm vaccine candidates?" PLOS Neglected Tropical Diseases 16, no. 12 (December 22, 2022): e0010933. http://dx.doi.org/10.1371/journal.pntd.0010933.
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Trichuris trichiura and T. suis are gastrointestinal dwelling roundworms that infect humans and pigs, respectively. Heavy infections cause gastrointestinal symptoms and impaired growth and development. Vaccination has the potential to reduce the disease burden of whipworm infection; however, there are currently no commercially available vaccines against these parasites and very few against other gastrointestinal-dwelling nematodes of medical and agricultural importance. The naturally occurring mouse whipworm, T. muris, has been used for decades to model human trichuriasis, and the immunogenic potential of the excretory/secretory material (E/S, which can be collected following ex vivo culture of worms) has been studied in the context of vaccine candidate identification. Despite this, researchers are yet to progress an effective vaccine candidate to clinical trials. The T. muris, T. trichiura, and T. suis genomes each encode between 10 and 27 whey acidic protein (WAP) domain-containing proteins and 15 to 34 cysteine-rich secretory protein/antigen 5/pathogenesis related-1 (CAP) family members. WAP and CAP proteins have been postulated to play key roles in host–parasite interactions and may possess immunomodulatory functions. In addition, both protein families have been explored in the context of helminth vaccines. Here, we use phylogenetic and functional analysis to investigate the evolutionary relationship between WAP and CAP proteins encoded by T. muris, T. trichiura, and T. suis. We highlight several WAP and CAP proteins that warrant further study to understand their biological function and as possible vaccine candidates against T. trichiura and/or T. suis, based on the close evolutionary relationship with WAP or CAP proteins identified within T. muris E/S products.
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Koul, Anil, Axel Choidas, Martin Treder, Anil K. Tyagi, Karl Drlica, Yogendra Singh, and Axel Ullrich. "Cloning and Characterization of Secretory Tyrosine Phosphatases of Mycobacterium tuberculosis." Journal of Bacteriology 182, no. 19 (October 1, 2000): 5425–32. http://dx.doi.org/10.1128/jb.182.19.5425-5432.2000.
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ABSTRACT Two genes with sequence homology to those encoding protein tyrosine phosphatases were cloned from genomic DNA of Mycobacterium tuberculosis H37Rv. The calculated molecular masses of these two putative tyrosine phosphatases, designated MPtpA and MPtpB, were 17.5 and 30 kDa, respectively. MPtpA and MPtpB were expressed as glutathione S-transferase fusion proteins inEscherichia coli. The affinity-purified proteins dephosphorylated the phosphotyrosine residue of myelin basic protein (MBP), but they failed to dephosphorylate serine/threonine residues of MBP. The activity of these phosphatases was inhibited by sodium orthovanadate, a specific inhibitor of tyrosine phosphatases, but not by okadaic acid, an inhibitor of serine/threonine phosphatases. Mutations at the catalytic site motif, cysteine 11 of MPtpA and cysteine 160 of MPtpB, abolished enzyme activity. Southern blot analysis revealed that, while mptpA is present in slow-growing mycobacterial species as well as fast-growing saprophytes,mptpB was restricted to members of the M. tuberculosis complex. These phosphatases were present in both whole-cell lysates and culture filtrates of M. tuberculosis, suggesting that these proteins are secreted into the extracellular medium. Since tyrosine phosphatases are essential for the virulence of several pathogenic bacteria, the restricted distribution of mptpB makes it a good candidate for a virulence gene of M. tuberculosis.
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Watson, Patricia R., Edouard E. Galyov, Sue M. Paulin, Philip W. Jones, and Tim S. Wallis. "Mutation of invH, but Notstn, Reduces Salmonella-Induced Enteritis in Cattle." Infection and Immunity 66, no. 4 (April 1, 1998): 1432–38. http://dx.doi.org/10.1128/iai.66.4.1432-1438.1998.
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ABSTRACT The induction of secretory and inflammatory responses in calves bySalmonella typhimurium and Salmonella dublinstrains was compared, and the effects of mutations in theinvH and stn genes were assessed. S. typhimurium induced greater secretory and inflammatory responses than S. dublin in bovine ileal loops, despite the fact that these serotypes were recovered from bovine ileal mucosa in comparable numbers (P. R. Watson, S. M. Paulin, A. P. Bland, P. W. Jones, and T. S. Wallis, Infect. Immun. 63:2743–2754, 1995). These results implicate serotype-specific factors other than, or in addition to, intestinal invasion in the induction of enteritis. The secretory and inflammatory responses induced by S. typhimurium and S. dublin in bovine ligated ileal loops were not significantly altered by mutation of stn, which suggests that stn does not have a major role inSalmonella-induced enteritis. The invH mutation significantly reduced the secretory and inflammatory responses induced in bovine ileal loops, and this correlated with a reduction in the severity of enteritis following oral inoculation of calves. The attenuation associated with the invH mutation did not appear to be due to an increased susceptibility to the innate host defense mechanisms, because the resistance of S. typhimurium to the bactericidal action of either bovine polymorphonuclear leukocytes or bovine serum was not significantly altered. However, lysis of macrophages following infection withS. typhimurium was significantly reduced by theinvH mutation. The invH mutation prevented the normal secretion of several proteins, including SipC, by S. typhimurium, indicating that the function of theinv-spa-encoded type III protein secretion system was disrupted. Taken together, these observations implicateinv-spa-dependent effectors in mediation ofSalmonella-induced enteritis in cattle. Clearly, however, other undefined serotype-specific virulence factors are also involved in Salmonella-induced enteritis.
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MAK, C. H., and R. C. KO. "DNA-binding activity in the excretory–secretory products ofTrichinella pseudospiralis(Nematoda: Trichinelloidea)." Parasitology 123, no. 3 (March 2001): 301–8. http://dx.doi.org/10.1017/s0031182001008459.
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A novel DNA-binding peptide ofMr∼30 kDa was documented for the first time in the excretory–secretory (E–S) products of the infective-stage larvae ofTrichinella pseudospiralis.Larvae recovered from muscles of infected mice were maintained for 48 h in DMEM medium. E–S products of worms extracted from the medium were analysed for DNA-binding activity by the electrophoretic mobility shift assay (EMSA). Multiple DNA-protein complexes were detected. A comparison of theMrof proteins in the complexes indicated that they could bind to the target DNA as a dimer, tetramer or multiples of tetramers. Site selection and competition analysis showed that the binding has a low specificity. A (G/C-rich)-gap-(G/T-rich)-DNA sequence pattern was extracted from a pool of degenerate PCR fragments binding to the E–S products. Results of immunoprecipitation and electrophoretic mobility supershift assay confirmed the authenticity of the DNA-binding protein as an E–S product.
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Kwon, Min Jin, Mark Arentshorst, Markus Fiedler, Florence L. M. de Groen, Peter J. Punt, Vera Meyer, and Arthur F. J. Ram. "Molecular genetic analysis of vesicular transport in Aspergillus niger reveals partial conservation of the molecular mechanism of exocytosis in fungi." Microbiology 160, no. 2 (February 1, 2014): 316–29. http://dx.doi.org/10.1099/mic.0.074252-0.
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The filamentous fungus Aspergillus niger is an industrially exploited protein expression platform, well known for its capacity to secrete high levels of proteins. To study the process of protein secretion in A. niger, we established a GFP-v-SNARE reporter strain in which the trafficking and dynamics of secretory vesicles can be followed in vivo. The biological role of putative A. niger orthologues of seven secretion-specific genes, known to function in key aspects of the protein secretion machinery in Saccharomyces cerevisiae, was analysed by constructing respective gene deletion mutants in the GFP-v-SNARE reporter strain. Comparison of the deletion phenotype of conserved proteins functioning in the secretory pathway revealed common features but also interesting differences between S. cerevisiae and A. niger. Deletion of the S. cerevisiae Sec2p orthologue in A. niger (SecB), encoding a guanine exchange factor for the GTPase Sec4p (SrgA in A. niger), did not have an obvious phenotype, while SEC2 deletion in S. cerevisiae is lethal. Similarly, deletion of the A. niger orthologue of the S. cerevisiae exocyst subunit Sec3p (SecC) did not result in a lethal phenotype as in S. cerevisiae, although severe growth reduction of A. niger was observed. Deletion of secA, secH and ssoA (encoding SecA, SecH and SsoA the A. niger orthologues of S. cerevisiae Sec1p, Sec8p and Sso1/2p, respectively) showed that these genes are essential for A. niger, similar to the situation in S. cerevisiae. These data demonstrate that the orchestration of exocyst-mediated vesicle transport is only partially conserved in S. cerevisiae and A. niger.
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Prašnikar, Erika, Jure Knez, Borut Kovačič, and Tanja Kunej. "Molecular signature of eutopic endometrium in endometriosis based on the multi-omics integrative synthesis." Journal of Assisted Reproduction and Genetics 37, no. 7 (May 30, 2020): 1593–611. http://dx.doi.org/10.1007/s10815-020-01833-3.
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Abstract Purpose To synthesise data from genome-wide studies reporting molecular signature of eutopic endometrium through the phases of the menstrual cycle in endometriosis. Methods Extraction of data from publications reporting genetic signatures characterising endometrium associated with endometriosis. The nomenclature of extracted differentially expressed transcripts and proteins was adopted according to the HUGO Gene Nomenclature Committee (HGNC). Loci were further sorted according to the different phases of the menstrual cycle, i.e. menstrual (M), proliferative (P), secretory (S), early-secretory (ES), mid-secretory (MS), late-secretory (LS), and not specified (N/S) if the endometrial dating was not available. Enrichment analysis was performed using the DAVID bioinformatics tool. Results Altered molecular changes were reported by 21 studies, including 13 performed at the transcriptomic, 6 at proteomic, and 2 at epigenomic level. Extracted data resulted in a catalogue of total 670 genetic causes with available 591 official gene symbols, i.e. M = 3, P = 188, S = 81, ES = 82, MS = 173, LS = 36, and N/S = 28. Enriched pathways included oestrogen signalling pathway, extracellular matrix organization, and endothelial cell chemotaxis. Our study revealed that knowledge of endometrium biology in endometriosis is fragmented due to heterogeneity of published data. However, 15 genes reported as dysregulated by at least two studies within the same phase and 33 significantly enriched GO-BP terms/KEGG pathways associated with different phases of the menstrual cycle were identified. Conclusions A multi-omics insight into molecular patterns underlying endometriosis could contribute towards identification of endometrial pathological mechanisms that impact fertility capacities of women with endometriosis.
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Zinkevičiūtė, Rūta, Raimundas Ražanskas, Algirdas Kaupinis, Neringa Macijauskaitė, Evaldas Čiplys, Gunnar Houen, and Rimantas Slibinskas. "Yeast Secretes High Amounts of Human Calreticulin without Cellular Stress." Current Issues in Molecular Biology 44, no. 5 (April 19, 2022): 1768–87. http://dx.doi.org/10.3390/cimb44050122.
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The ER chaperone calreticulin (CALR) also has extracellular functions and can exit the mammalian cell in response to various factors, although the mechanism by which this takes place is unknown. The yeast Saccharomyces cerevisiae efficiently secretes human CALR, and the analysis of this process in yeast could help to clarify how it gets out of eukaryotic cells. We have achieved a secretion titer of about 140 mg/L CALR in our S. cerevisiae system. Here, we present a comparative quantitative whole proteome study in CALR-secreting yeast using non-equilibrium pH gradient electrophoresis (NEPHGE)-based two-dimensional gel electrophoresis (2DE) as well as liquid chromatography mass spectrometry in data-independent analysis mode (LC-MSE). A reconstructed carrier ampholyte (CA) composition of NEPHGE-based first-dimension separation for 2DE could be used instead of formerly commercially available gels. Using LC-MSE, we identified 1574 proteins, 20 of which exhibited differential expression. The largest group of differentially expressed proteins were structural ribosomal proteins involved in translation. Interestingly, we did not find any signs of cellular stress which is usually observed in recombinant protein-producing yeast, and we did not identify any secretory pathway proteins that exhibited changes in expression. Taken together, high-level secretion of human recombinant CALR protein in S. cerevisiae does not induce cellular stress and does not burden the cellular secretory machinery. There are only small changes in the cellular proteome of yeast secreting CALR at a high level.
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Fukuda, M. "Rab27 and its effectors in secretory granule exocytosis: a novel docking machinery composed of a Rab27·effector complex." Biochemical Society Transactions 34, no. 5 (October 1, 2006): 691–95. http://dx.doi.org/10.1042/bst0340691.
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A small GTPase Rab27 is present on secretory granules in a wide variety of secretory cells and on melanosomes in melanocytes, and it is involved in controlling the trafficking of these organelles through interaction with a cell-type- or tissue-specific Rab27 effector(s). Slps (synaptotagmin-like proteins) and rabphilin contain an N-terminal Rab27-binding domain and C-terminal tandem C2 domains, and some of the Rab27-binding proteins have recently been shown to promote docking of Rab27-bound organelles to the plasma membrane. This mini-review presents a model for how the Rab27·effector complex controls the docking step in the trafficking of Rab27-bound organelles. Our results indicate that Slp2-a, Slp4-a/granuphilin-a and rabphilin are capable of interacting with the plasma membrane directly or indirectly, and thus that these Rab27 effectors form a bridge between Rab27-bound organelles and the plasma membrane.
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Brewer, Joseph W., and Suzanne Jackowski. "UPR-Mediated Membrane Biogenesis in B Cells." Biochemistry Research International 2012 (2012): 1–7. http://dx.doi.org/10.1155/2012/738471.
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The unfolded protein response (UPR) can coordinate the regulation of gene transcription and protein translation to balance the load of client proteins with the protein folding and degradative capacities of the ER. Increasing evidence also implicates the UPR in the regulation of lipid synthesis and membrane biogenesis. The differentiation of B lymphocytes into antibody-secreting cells is marked by significant expansion of the ER, the site for antibody synthesis and assembly. In activated B cells, the demand for membrane protein and lipid components leads to activation of the UPR transcriptional activator XBP1(S) which, in turn, initiates a cascade of biochemical events that enhance supplies of phospholipid precursors and build machinery for the synthesis, maturation, and transport of secretory proteins. The alterations in lipid metabolism that occur during this developmental transition and the impact of membrane phospholipid restriction on B cell secretory characteristics are discussed in this paper.
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SPINNER, W. G., F. J. THOMPSON, D. C. EMERY, and M. E. VINEY. "Characterization of genes with a putative key role in the parasitic lifestyle of the nematode Strongyloides ratti." Parasitology 139, no. 10 (May 2, 2012): 1317–28. http://dx.doi.org/10.1017/s0031182012000637.
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SUMMARYParasitic nematodes are significant pathogens of humans and other animals. The molecular and genetic basis of animal parasitism is not yet fully understood. Strongyloides spp. are a genus of gastrointestinal nematodes of which species infect approximately 100–200 million people worldwide. S. ratti is a natural parasite of the rat, and a useful and amenable laboratory model. Previous EST and microarray analyses of the S. ratti life cycle have identified genes whose expression was specific, or biased, to the parasitic adult stage, suggesting that they may play a key role in parasitism in this species. Here we have further investigated the expression of these genes (by RT-PCR) throughout the S. ratti life-cycle. We produced recombinant proteins in vitro for a subset of these genes, which were used in Western blot analyses to investigate the distribution of the gene products among different stages of the S. ratti life cycle. We tested the efficacy of these recombinant proteins as anti-S. ratti vaccines. One of the proteins was detected in the excretory/secretory products of the parasitic stages.
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Cantacessi, Cinzia, Jason Mulvenna, Neil D. Young, Martin Kasny, Petr Horak, Ammar Aziz, Andreas Hofmann, Alex Loukas, and Robin B. Gasser. "A Deep Exploration of the Transcriptome and “Excretory/Secretory” Proteome of Adult Fascioloides magna." Molecular & Cellular Proteomics 11, no. 11 (August 16, 2012): 1340–53. http://dx.doi.org/10.1074/mcp.m112.019844.
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Parasitic liver flukes of the family Fasciolidae are responsible for major socioeconomic losses worldwide. However, at present, knowledge of the fundamental molecular biology of these organisms is scant. Here, we characterize, for the first time, the transcriptome and secreted proteome of the adult stage of the “giant liver fluke,” Fascioloides magna, using Illumina sequencing technology and one-dimensional SDS-PAGE and OFFGEL protein electrophoresis, respectively. A total of ∼54,000,000 reads were generated and assembled into ∼39,000 contiguous sequences (contigs); ∼20,000 peptides were predicted and classified based on homology searches, protein motifs, gene ontology, and biological pathway mapping. From the predicted proteome, 48.1% of proteins could be assigned to 384 biological pathway terms, including “spliceosome,” “RNA transport,” and “endocytosis.” Putative proteins involved in amino acid degradation were most abundant. Of the 835 secreted proteins predicted from the transcriptome of F. magna, 80 were identified in the excretory/secretory products from this parasite. Highly represented were antioxidant proteins, followed by peptidases (particularly cathepsins) and proteins involved in carbohydrate metabolism. The integration of transcriptomic and proteomic datasets generated herein sets the scene for future studies aimed at exploring the potential role(s) that molecules might play at the host–parasite interface and for establishing novel strategies for the treatment or control of parasitic fluke infections.
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Shishodia, Sonia Kumari, and Jata Shankar. "Exploration of Mycelial Proteins from Aspergillus terreus Revealed Ribosome Biogenesis and Antioxidant Enzymes." Current Proteomics 17, no. 5 (July 16, 2020): 433–45. http://dx.doi.org/10.2174/1570164617666191004163734.
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Background: Aspergillus terreus is a major etiological agent among fungal pathogens and emerged as an opportunistic pathogen in immunocompromised patients. Methods: The mycelial proteins of A. terreus cultured for 48h at 37°C have been analysed by using nLC-ESI-MS/MS. Protein data analysis performed by Proteome Discoverer (V/2.2) against the UniProt database. Also, Scanning Electron Microscopy (SEM) analysis of biofilm formation under optimum conditions was carried out. qRT-PCR was carried out for genes encoding for functionally important proteins. Results: A total of 389 proteins were detected at FDR 0.01. Gene ontology showed the abundance of proteins from energy metabolism, cellular homeostasis, ribosome biogenesis, cell wall, and structural components. We observed catalase, superoxide dismutase, thioredoxin, glutathione S-transferase involved in redox homeostasis and heat shock proteins (Hsp90 and Hsp70). These proteins may provide insight into the resistance mechanism of A. terreus against AmB. Additionally, SEM analysis of A. terreus showed the formation of dense hyphal network covered with porous extracellular matrix (ECM). Using SECRETOOL, 8 proteins were predicted as secretory. Three proteins, such as glucanase Crf1/allergen (Asp F9), 1, 3-β-glucanosyltransferase and β-hexosaminidase were reported in biofilm establishment. Conclusion: Our proteome data provided experimental evidence to the annotated set of proteins in A. terreus that comprehend biochemical and cellular events involved in the establishment of mycelial network and contributing to the pathogenesis. This work also provides resource for further molecular studies in A. terreus.
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Nagano, Isao, Zhiliang Wu, and Yuzo Takahashi. "Species-Specific Antibody Responses to the Recombinant 53-Kilodalton Excretory and Secretory Proteins in Mice Infected with Trichinella spp." Clinical and Vaccine Immunology 15, no. 3 (January 9, 2008): 468–73. http://dx.doi.org/10.1128/cvi.00467-07.
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ABSTRACT The 53-kDa proteins in larval excretory and secretory (E-S) products were expressed from five Trichinella species (T. spiralis, T. britovi, T. nativa, T. pseudospiralis, and T. papuae), using the Escherichia coli expression system, and the antibody responses to the 53-kDa recombinant proteins in mice infected with Trichinella spp. were analyzed by Western blotting. The 53-kDa protein is conserved among the five Trichinella species, with >60% similarity in amino acid sequences. The 53-kDa recombinant proteins of T. spiralis and T. pseudospiralis reacted to sera from mice infected with T. spiralis and T. pseudospiralis at 8 days postinfection (p.i.), respectively. An antibody against the 53-kDa recombinant protein of T. spiralis recognized the 53-kDa protein in the crude extracts from adult worms and 30-day p.i. muscle larvae and E-S products from muscle larvae of T. spiralis but did not recognize any proteins from T. pseudospiralis. The sera from the mice infected with T. spiralis strongly reacted with the 53-kDa recombinant protein of T. spiralis but did not react with the 53-kDa recombinant proteins of T. britovi, T. nativa, T. pseudospiralis, and T. papuae. Similarly, the sera from mice infected with T. britovi, T. nativa, T. pseudospiralis, or T. papuae strongly reacted with the 53-kDa recombinant proteins of T. britovi, T. nativa, T. pseudospiralis, or T. papuae, respectively. These results showed that the 53-kDa recombinant proteins provide early and species-specific antibody responses in mice infected with Trichinella spp.
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Lemons, Paula P., Dong Chen, Audrey M. Bernstein, Mark K. Bennett, and S. W. Whiteheart. "Regulated Secretion in Platelets: Identification of Elements of the Platelet Exocytosis Machinery." Blood 90, no. 4 (August 15, 1997): 1490–500. http://dx.doi.org/10.1182/blood.v90.4.1490.
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Abstract To further characterize the molecular mechanisms of platelet function, we have sought to identify some of the proteins that mediate the secretory events of the platelet release reaction. We report that platelets contain the general elements of the membrane transport apparatus: N-ethylmaleimide sensitive fusion protein (NSF ), p115/transcytosis-associated protein (p115/TAP), and the soluble NSF attachment proteins (α- and, γ-SNAP). The cDNAs encoding two of these proteins, α- and γ-SNAP, have been cloned from a human platelet-derived cDNA library. Platelet membrane extracts possess SNAPreceptor (SNARE) activity, suggesting that the class of proteins (SNAREs) proposed to provide the specificity for vesicle docking and membrane fusion are present in platelets. To identify these proteins, we have used specific antibodies against known SNAREs to probe platelet extracts. Syntaxin 2 and 4 can be readily detected in platelet membrane preparations and are shown to participate in 20 S complex formation. Syntaxin 1, 3, and 5 could not be detected. Other known SNARE and SNARE-associated proteins such as vesicle-associated membrane protein (VAMP)/synaptobrevin 2, SNAP-25, synaptophysin, or synaptotagmin I could not be immunochemically detected in platelet membrane preparations. The presence of both the general transport proteins (NSF and SNAPs) and specific transport proteins (syntaxin 2 and 4) indicates that platelet exocytosis uses a molecular mechanism similar to other secretory cells such as neurons. However, the subcellular concentrations of these proteins suggest that, unlike neuronal secretion, granule-to plasma membrane docking may be the limiting step in platelet exocytosis.
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Lemons, Paula P., Dong Chen, Audrey M. Bernstein, Mark K. Bennett, and S. W. Whiteheart. "Regulated Secretion in Platelets: Identification of Elements of the Platelet Exocytosis Machinery." Blood 90, no. 4 (August 15, 1997): 1490–500. http://dx.doi.org/10.1182/blood.v90.4.1490.1490_1490_1500.
Full textAbstract:
To further characterize the molecular mechanisms of platelet function, we have sought to identify some of the proteins that mediate the secretory events of the platelet release reaction. We report that platelets contain the general elements of the membrane transport apparatus: N-ethylmaleimide sensitive fusion protein (NSF ), p115/transcytosis-associated protein (p115/TAP), and the soluble NSF attachment proteins (α- and, γ-SNAP). The cDNAs encoding two of these proteins, α- and γ-SNAP, have been cloned from a human platelet-derived cDNA library. Platelet membrane extracts possess SNAPreceptor (SNARE) activity, suggesting that the class of proteins (SNAREs) proposed to provide the specificity for vesicle docking and membrane fusion are present in platelets. To identify these proteins, we have used specific antibodies against known SNAREs to probe platelet extracts. Syntaxin 2 and 4 can be readily detected in platelet membrane preparations and are shown to participate in 20 S complex formation. Syntaxin 1, 3, and 5 could not be detected. Other known SNARE and SNARE-associated proteins such as vesicle-associated membrane protein (VAMP)/synaptobrevin 2, SNAP-25, synaptophysin, or synaptotagmin I could not be immunochemically detected in platelet membrane preparations. The presence of both the general transport proteins (NSF and SNAPs) and specific transport proteins (syntaxin 2 and 4) indicates that platelet exocytosis uses a molecular mechanism similar to other secretory cells such as neurons. However, the subcellular concentrations of these proteins suggest that, unlike neuronal secretion, granule-to plasma membrane docking may be the limiting step in platelet exocytosis.
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MARÉCHAL, Alexandre, Pierre-Luc TANGUAY, Mario CALLEJO, Renée GUÉRIN, Guy BOILEAU, and Luis A. ROKEACH. "Cell viability and secretion of active proteins in Schizosaccharomyces pombe do not require the chaperone function of calnexin." Biochemical Journal 380, no. 2 (June 1, 2004): 441–48. http://dx.doi.org/10.1042/bj20031546.
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Folding of newly synthesized proteins within the ER (endoplasmic reticulum) is a rate-limiting step in protein secretion. Thus ER molecular chaperones and foldases have a major impact in determining the rate and yield of these crucial cellular processes. Calnexin is a key ER chaperone implicated in the folding, retention and targeting for degradation of proteins that go through the secretory pathway. Calnexin molecules contain a highly conserved central domain (hcd) that has been proposed to be involved in the interaction with folding substrates and other chaperones. To gain a better understanding of the roles played by calnexin in the secretory pathway, we examined the efficiency of fission yeast (Schizosaccharomyces pombe) strains expressing calnexin mutants to secrete different model proteins. Remarkably, calnexin hcd-deletion mutants, although devoid of detectable chaperone activity in vitro, confer viability and cause a considerable increase in the secretion of heterologous cellulase. Surprisingly the quality-control efficiency, measured as the activity/amount ratio of secreted model protein, was not severely reduced in these calnexin hcd-deletion mutant strains. Our results indicate that the essential function of calnexin does not reside in its role in the folding or in the retention of misfolded proteins. These observations suggest the existence of a highly stringent quality control mechanism in the ER of S. pombe that might reduce the secretion efficiency of endogenous proteins.
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Buerth, Christoph, Clemens J. Heilmann, Frans M. Klis, Chris G. de Koster, Joachim F. Ernst, and Denis Tielker. "Growth-dependent secretome of Candida utilis." Microbiology 157, no. 9 (September 1, 2011): 2493–503. http://dx.doi.org/10.1099/mic.0.049320-0.
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Recently, the food yeast Candida utilis has emerged as an excellent host for production of heterologous proteins. Since secretion of the recombinant product is advantageous for its purification, we characterized the secreted proteome of C. utilis. Cells were cultivated to the exponential or stationary growth phase, and the proteins in the medium were identified by MS. In parallel, a draft genome sequence of C. utilis strain DSM 2361 was determined by massively parallel sequencing. Comparisons of protein and coding sequences established that C. utilis is not a member of the CUG clade of Candida species. In total, we identified 37 proteins in the culture solution, 17 of which were exclusively present in the stationary phase, whereas three proteins were specific to the exponential growth phase. Identified proteins represented mostly carbohydrate-active enzymes associated with cell wall organization, while no proteolytic enzymes and only a few cytoplasmic proteins were detected. Remarkably, cultivation in xylose-based medium generated a protein pattern that diverged significantly from glucose-grown cells, containing the invertase Inv1 as the major extracellular protein, particularly in its highly glycosylated S-form (slow-migrating). Furthermore, cultivation without ammonium sulfate induced the secretion of the asparaginase Asp3. Comparisons of the secretome of C. utilis with those of Kluyveromyces lactis and Pichia pastoris, as well as with those of the human fungal pathogens Candida albicans and Candida glabrata, revealed a conserved set of 10 and six secretory proteins, respectively.
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Pian, M. S., and L. G. Dobbs. "Activation of G proteins may inhibit or stimulate surfactant secretion in rat alveolar type II cells." American Journal of Physiology-Lung Cellular and Molecular Physiology 266, no. 4 (April 1, 1994): L375—L381. http://dx.doi.org/10.1152/ajplung.1994.266.4.l375.
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To investigate how G proteins regulate surfactant secretion, we subjected rat alveolar type II cells to conditions known to activate or to inactivate G proteins. AlF-4, which activates G proteins, inhibited secretion in intact cells. Guanosine-5'-O-(3-thiotriphosphate), which activates G proteins in permeabilized cells, stimulated secretion at basal cytosolic [Ca2+], but inhibited secretion at higher [Ca2+]. In contrast, guanosine-5'-O-(2-thiodiphosphate) (GDP beta S), which inactivates G proteins, stimulated secretion at each [Ca2+] tested. Because treatment with GDP beta S stimulated secretion at basal cytosolic [Ca2+], surfactant secretion appears to be subject to G protein-regulated tonic inhibition. Pertussis toxin (PTX) inhibited terbutaline- and ionomycin-stimulated secretion in intact cells, but did not inhibit secretion stimulated by either forskolin or 8-bromoadenosine 3',5'-cyclic monophosphate. Inhibition by PTX of terbutaline-stimulated, but not 8-bromoadenosine 3',5'-cyclic monophosphate- or forskolin-stimulated secretion, suggests that PTX-sensitive G proteins regulate beta-adrenergic-stimulated surfactant secretion proximal to second messenger generation. Inhibition of ionomycin-stimulated secretion, however, suggests that PTX-sensitive G proteins may also regulate non-receptor-mediated secretory events.
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Cao, Zhe, and Sabine Banniza. "Cross-Kingdom Gene Coexpression Analysis Using a Stemphylium botryosum–Lens ervoides System Revealed Plasticity of Intercommunication Between the Pathogen Secretome and the Host Immune Systems." Molecular Plant-Microbe Interactions® 34, no. 12 (December 2021): 1365–77. http://dx.doi.org/10.1094/mpmi-05-21-0112-r.
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Necrotrophic pathogens are responsible for significant declines in crop yield and quality worldwide. During the infection process, a pathogen releases a series of secretory proteins to counteract the plant immune system, and this interaction of pathogen and host molecules determines whether the pathogen will successfully invade the host plant tissues. In this study, we adopted co-transcriptomic approaches to analyze the Lens ervoides–Stemphylium botryosum system, with a focus on 1,216 fungal genes coding for secretory proteins and 8,810 disease-responsive genes of the host 48, 96, and 144 h postinoculation, captured in two F9 recombinant inbred lines (RILs) displaying contrasting disease responses. By constructing in planta gene coexpression networks (GCNs) for S. botryosum, we found that the pathogen tended to co-upregulate genes regulating cell wall degradation enzymes, effectors, oxidoreductases, and peptidases to a much higher degree in the susceptible host LR-66-577 than in the resistant RIL LR-66-637, indicating that the promotion of these digestive enzymes and toxins increased S. botryosum virulence. Construction of cross-kingdom GCNs between pathogen and plant for the two RILs revealed that the co-upregulation of these fungal digestive enzymes and toxins simultaneously promoted a series of defense responses such as redox change, expression of membrane-related genes and serine/threonine kinase, and stress and disease responses in the susceptible RIL which was not observed in the resistant RIL, indicating that these activities exacerbated susceptibility to S. botryosum. [Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .
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Klumperman, Judith, Regina Kuliawat, Janice M. Griffith, Hans J. Geuze, and Peter Arvan. "Mannose 6–Phosphate Receptors Are Sorted from Immature Secretory Granules via Adaptor Protein AP-1, Clathrin, and Syntaxin 6–positive Vesicles." Journal of Cell Biology 141, no. 2 (April 20, 1998): 359–71. http://dx.doi.org/10.1083/jcb.141.2.359.
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The occurrence of clathrin-coated buds on immature granules (IGs) of the regulated secretory pathway suggests that specific transmembrane proteins are sorted into these buds through interaction with cytosolic adaptor proteins. By quantitative immunoelectron microscopy of rat endocrine pancreatic β cells and exocrine parotid and pancreatic cells, we show for the first time that the mannose 6–phosphate receptors (MPRs) for lysosomal enzyme sorting colocalize with the AP-1 adaptor in clathrin-coated buds on IGs. Furthermore, the concentrations of both MPR and AP-1 decline by ∼90% as the granules mature. Concomitantly, in exocrine secretory cells lysosomal proenzymes enter and then are sorted out of IGs, just as was previously observed in β cells (Kuliawat, R., J. Klumperman, T. Ludwig, and P. Arvan. 1997. J. Cell Biol. 137:595–608). The exit of MPRs in AP-1/clathrin-coated buds is selective, indicated by the fact that the membrane protein phogrin is not removed from maturing granules. We have also made the first observation of a soluble N-ethylmaleimide–sensitive factor attachment protein receptor, syntaxin 6, which has been implicated in clathrin-coated vesicle trafficking from the TGN to endosomes (Bock, J.B., J. Klumperman, S. Davanger, and R.H. Scheller. 1997. Mol. Biol. Cell. 8:1261–1271) that enters and then exits the regulated secretory pathway during granule maturation. Thus, we hypothesize that during secretory granule maturation, MPR–ligand complexes and syntaxin 6 are removed from IGs by AP-1/clathrin-coated vesicles, and then delivered to endosomes.
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Bryant, Nia J., and Tom H. Stevens. "Vacuole Biogenesis in Saccharomyces cerevisiae: Protein Transport Pathways to the Yeast Vacuole." Microbiology and Molecular Biology Reviews 62, no. 1 (March 1, 1998): 230–47. http://dx.doi.org/10.1128/mmbr.62.1.230-247.1998.
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SUMMARY Delivery of proteins to the vacuole of the yeast Saccharomyces cerevisiae provides an excellent model system in which to study vacuole and lysosome biogenesis and membrane traffic. This organelle receives proteins from a number of different routes, including proteins sorted away from the secretory pathway at the Golgi apparatus and endocytic traffic arising from the plasma membrane. Genetic analysis has revealed at least 60 genes involved in vacuolar protein sorting, numerous components of a novel cytoplasm-to-vacuole transport pathway, and a large number of proteins required for autophagy. Cell biological and biochemical studies have provided important molecular insights into the various protein delivery pathways to the yeast vacuole. This review describes the various pathways to the vacuole and illustrates how they are related to one another in the vacuolar network of S. cerevisiae.
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Lontok, Erik, Emily Corse, and Carolyn E. Machamer. "Intracellular Targeting Signals Contribute to Localization of Coronavirus Spike Proteins near the Virus Assembly Site." Journal of Virology 78, no. 11 (June 1, 2004): 5913–22. http://dx.doi.org/10.1128/jvi.78.11.5913-5922.2004.
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ABSTRACT Coronavirus budding at the endoplasmic reticulum-Golgi intermediate compartment (ERGIC) requires accumulation of the viral envelope proteins at this point in the secretory pathway. Here we demonstrate that the spike (S) protein from the group 3 coronavirus infectious bronchitis virus (IBV) contains a canonical dilysine endoplasmic reticulum retrieval signal (-KKXX-COOH) in its cytoplasmic tail. This signal can retain a chimeric reporter protein in the ERGIC and when mutated allows transport of the full-length S protein as well as the chimera to the plasma membrane. Interestingly, the IBV S protein also contains a tyrosine-based endocytosis signal in its cytoplasmic tail, suggesting that any S protein that escapes the ERGIC will be rapidly endocytosed when it reaches the plasma membrane. We also identified a novel dibasic motif (-KXHXX-COOH) in the cytoplasmic tails of S proteins from group 1 coronaviruses and from the newly identified coronavirus implicated in severe acute respiratory syndrome. This dibasic motif also retained a reporter protein in the ERGIC, similar to the dilysine motif in IBV S. The cytoplasmic tails of S proteins from group 2 coronaviruses lack an intracellular localization signal. The inherent differences in S-protein trafficking could point to interesting variations in pathogenesis of coronaviruses, since increased levels of surface S protein could promote syncytium formation and direct cell-to-cell spread of the infection.
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Norman, J. C., L. S. Price, A. J. Ridley, and A. Koffer. "The small GTP-binding proteins, Rac and Rho, regulate cytoskeletal organization and exocytosis in mast cells by parallel pathways." Molecular Biology of the Cell 7, no. 9 (September 1996): 1429–42. http://dx.doi.org/10.1091/mbc.7.9.1429.
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In mast cells, activation of GTP-binding proteins induces centripetal reorganization of actin filaments. This effect is due to disassembly, relocalization, and polymerization of F-actin and is dependent on two small GTPases, Rac and Rho. Activities of Rac and Rho are also essential for the secretory function of mast cells. In response to GTP-gamma-S and/or calcium, only a proportion of permeabilized mast cells is capable of secretory response. Here, we have compared actin organization of secreting and nonsecreting cell populations. We show that the cytoskeletal and secretory responses are strongly correlated, indicating a common upstream regulator of the two functions. The secreting cell population preferentially displays both relocalization and polymerization of actin. However, when actin relocalization or polymerization is inhibited by phalloidin or cytochalasin, respectively, secretion is unaffected. Moreover, the ability of the constitutively active mutants of Rac and Rho to enhance secretion is also unaffected in the presence of cytochalasin. Therefore, Rac and Rho control these two functions by divergent, parallel signaling pathways. Cortical actin disassembly occurs in both secreting and nonsecreting populations and does not, by itself, induce exocytosis. A model for the control of exocytosis is proposed that includes at least four GTP-binding proteins and suggests the presence of both shared and divergent signaling pathways from Rac and Rho.
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Palacín, Arantxa, Ricardo de la Fuente, Inmaculada Valle, Luis A. Rivas, and Rafael P. Mellado. "Streptomyces lividans contains a minimal functional signal recognition particle that is involved in protein secretion." Microbiology 149, no. 9 (September 1, 2003): 2435–42. http://dx.doi.org/10.1099/mic.0.26313-0.
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The bacterial version of the mammalian signal recognition particle (SRP) is well conserved and essential to all known bacteria. The genes for the Streptomyces lividans SRP components have been cloned and characterized. FtsY resembles the mammalian SRP receptor and the S. lividans SRP consists of Ffh, a homologue of the mammalian SRP54 protein, and scRNA, which is a small size RNA of 82 nt in length. Co-immunoprecipitation studies confirmed that Ffh and scRNA are probably the only components of the S. lividans SRP and that pre-agarase can co-immunoprecipitate with Ffh, suggesting that the SRP is involved in targeting secretory proteins.