Journal articles: 'Cell envelope biogenesi'

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Yang, Yu, Song Qin, Fangqing Zhao, Xiaoyuan Chi, and Xiaowen Zhang. "Comparison of Envelope-Related Genes in Unicellular and Filamentous Cyanobacteria." Comparative and Functional Genomics 2007 (2007): 1–10. http://dx.doi.org/10.1155/2007/25751.

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To elucidate the evolution of cyanobacterial envelopes and the relation between gene content and environmental adaptation, cell envelope structures and components of unicellular and filamentous cyanobacteria were analyzed in comparative genomics. Hundreds of envelope biogenesis genes were divided into 5 major groups and annotated according to their conserved domains and phylogenetic profiles. Compared to unicellular species, the gene numbers of filamentous cyanobacteria expanded due to genome enlargement effect, but only few gene families amplified disproportionately, such as those encoding waaG and glycosyl transferase 2. Comparison of envelope genes among various species suggested that the significant variance of certain cyanobacterial envelope biogenesis genes should be the response to their environmental adaptation, which might be also related to the emergence of filamentous shapes with some new functions.

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Zhang, Junya, Shan Wu, Susan K. Boehlein, Donald R. McCarty, Gaoyuan Song, Justin W. Walley, Alan Myers, and A. Mark Settles. "Maize defective kernel5 is a bacterial TamB homologue required for chloroplast envelope biogenesis." Journal of Cell Biology 218, no. 8 (June 24, 2019): 2638–58. http://dx.doi.org/10.1083/jcb.201807166.

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Chloroplasts are of prokaryotic origin with a double-membrane envelope separating plastid metabolism from the cytosol. Envelope membrane proteins integrate chloroplasts with the cell, but envelope biogenesis mechanisms remain elusive. We show that maize defective kernel5 (dek5) is critical for envelope biogenesis. Amyloplasts and chloroplasts are larger and reduced in number in dek5 with multiple ultrastructural defects. The DEK5 protein is homologous to rice SSG4, Arabidopsis thaliana EMB2410/TIC236, and Escherichia coli tamB. TamB functions in bacterial outer membrane biogenesis. DEK5 is localized to the envelope with a topology analogous to TamB. Increased levels of soluble sugars in dek5 developing endosperm and elevated osmotic pressure in mutant leaf cells suggest defective intracellular solute transport. Proteomics and antibody-based analyses show dek5 reduces levels of Toc75 and chloroplast envelope transporters. Moreover, dek5 chloroplasts reduce inorganic phosphate uptake with at least an 80% reduction relative to normal chloroplasts. These data suggest that DEK5 functions in plastid envelope biogenesis to enable transport of metabolites and proteins.

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Prajnaparamita, Kandida, and Siti Susanti. "KARAKTER MORFOLOGIS DAN PERKEMBANGAN ANATOMIS BIJI MELINJO (Gnetum gnemon L.)." Biogenesis 17, no. 2 (August 23, 2021): 49. http://dx.doi.org/10.31258/biogenesis.17.2.49-60.

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Melinjo seeds (Gnetum gnemon L.) have many benefits, that it is necessary to know its morphological and anatomical characters. This study aimed to determine differences in morphological characters and anatomical development of melinjo seeds at four seed maturity stages. The morphological observation was carried out based on the quantitative and organoleptic characteristics of the melinjo seeds: outer envelope, size, and the color of the middle envelope. Seed development was anatomically observed in slides prepared with a non-embedding method using a sliding microtome then observed through a microscope. The outer seed envelope has a green to blackish-red color in the final stage, while the seed middle envelope has a light-brown to dark-brown in the final stage. The inner seed envelope is thin, non-rigid, and attached on the outside of the endosperm. The seeds' length ranges from ±1,5 cm until ±2,25 cm at the end-stage; seeds width are 1 cm – 1,18 cm; seeds diameter are 1 cm – 1,16 cm. The anatomical development showed tissue thickening and differentiation. The middle envelope is getting thicker: 318,84 μm to 397,29 μm. Endosperm tissue cells undergo cell compaction as the seeds ripen. At the same time, embryonic tissue differentiation forms hypocotyl, epicotyl, and cotyledon.

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Sodeik, B., R. W. Doms, M. Ericsson, G. Hiller, C. E. Machamer, W. van 't Hof, G. van Meer, B. Moss, and G. Griffiths. "Assembly of vaccinia virus: role of the intermediate compartment between the endoplasmic reticulum and the Golgi stacks." Journal of Cell Biology 121, no. 3 (May 1, 1993): 521–41. http://dx.doi.org/10.1083/jcb.121.3.521.

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Vaccinia virus, the prototype of the Poxviridae, is a large DNA virus which replicates in the cytoplasm of the host cell. The assembly pathway of vaccinia virus displays several unique features, such as the production of two structurally distinct, infectious forms. One of these, termed intracellular naked virus (INV), remains cells associated while the other, termed extracellular enveloped virus (EEV), is released from the cell. In addition, it has long been believed that INVs acquire their lipid envelopes by a unique example of de novo membrane biogenesis. To examine the structure and assembly of vaccinia virus we have used immunoelectron microscopy using antibodies to proteins of different subcellular compartments as well as a phospholipid analysis of purified INV and EEV. Our data are not consistent with the de novo model of viral membrane synthesis but rather argue that the vaccinia virus DNA becomes enwrapped by a membrane cisterna derived from the intermediate compartment between the ER and the Golgi stacks, thus acquiring two membranes in one step. Phospholipid analysis of purified INV supports its derivation from an early biosynthetic compartment. This unique assembly process is repeated once more when the INV becomes enwrapped by an additional membrane cisterna, in agreement with earlier reports. The available data suggest that after fusion between the outer envelope and the plasma membrane, mature EEV is released from the cell.

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Senior, A., and L. Gerace. "Integral membrane proteins specific to the inner nuclear membrane and associated with the nuclear lamina." Journal of Cell Biology 107, no. 6 (December 1, 1988): 2029–36. http://dx.doi.org/10.1083/jcb.107.6.2029.

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We obtained a monoclonal antibody (RL13) that identifies three integral membrane proteins specific to the nuclear envelope of rat liver, a major 75-kD polypeptide and two more minor components of 68 and 55 kD. Immunogold labeling of isolated nuclear envelopes demonstrates that these antigens are localized specifically to the inner nuclear membrane, and that the RL13 epitope occurs on the inner membrane's nucleoplasmic surface where the nuclear lamina is found. When nuclear envelopes are extracted with solutions containing nonionic detergent and high salt to solubilize nuclear membranes and pore complexes, most of these integral proteins remain associated with the insoluble lamina. Since the polypeptides recognized by RL13 are relatively abundant, they may function as lamina attachment sites in the inner nuclear membrane. Major cross-reacting antigens are found by immunoblotting and immunofluorescence microscopy in all rat cells examined. Therefore, these integral proteins are biochemical markers for the inner nuclear membrane and will be useful models for studying nuclear membrane biogenesis.

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Jackson, Mary, Michael R. McNeil, and Patrick J. Brennan. "Progress in targeting cell envelope biogenesis inMycobacterium tuberculosis." Future Microbiology 8, no. 7 (July 2013): 855–75. http://dx.doi.org/10.2217/fmb.13.52.

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Siegel, Sara D., Jun Liu, and Hung Ton-That. "Biogenesis of the Gram-positive bacterial cell envelope." Current Opinion in Microbiology 34 (December 2016): 31–37. http://dx.doi.org/10.1016/j.mib.2016.07.015.

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Poliquin, L., G. Levine, and G. C. Shore. "Involvement of Golgi apparatus and a restructured nuclear envelope during biogenesis and transport of herpes simplex virus glycoproteins." Journal of Histochemistry & Cytochemistry 33, no. 9 (September 1985): 875–83. http://dx.doi.org/10.1177/33.9.2991363.

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Following infection of BHK-21 cells with Herpes simplex virus type 1 (HSV-1), progeny nucleocapsids in the nucleus acquire a glycoprotein-rich envelope by budding through host-cell nuclear membranes. To investigate the nature of the glycoprotein products assembled in the virion at the nuclear envelope, infected cells were pulse-labeled with [3H]-mannose, an oligosaccharidal core sugar, or [3H]-fucose, a terminal sugar. After various chase periods, the incorporation of these sugars was monitored by electron microscope radioautography. The results show that HSV glycoproteins accumulate very rapidly in nuclear membranes, where they exist only as core-glycosylated precursors, i.e., containing [3H]-mannose but not [3H]-fucose. [3H]-fucose grains are seen mainly over Golgi membranes and over virions located in the Golgi and in other cytoplasmic vesicular structures. Our data support a model where addition of terminal sugars (e.g., fucose) to HSV-1 glycoprotein precursors can occur at the surface of newly enveloped viral particles as the virions themselves egress from the cell via the Golgi apparatus.

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Lorenzo, María M., Juana M. Sánchez-Puig, and Rafael Blasco. "Mutagenesis of the palmitoylation site in vaccinia virus envelope glycoprotein B5." Journal of General Virology 93, no. 4 (April 1, 2012): 733–43. http://dx.doi.org/10.1099/vir.0.039016-0.

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The outer envelope of vaccinia virus extracellular virions is derived from intracellular membranes that, at late times in infection, are enriched in several virus-encoded proteins. Although palmitoylation is common in vaccinia virus envelope proteins, little is known about the role of palmitoylation in the biogenesis of the enveloped virus. We have studied the palmitoylation of B5, a 42 kDa type I transmembrane glycoprotein comprising a large ectodomain and a short (17 aa) cytoplasmic tail. Mutation of two cysteine residues located in the cytoplasmic tail in close proximity to the transmembrane domain abrogated palmitoylation of the protein. Virus mutants expressing non-palmitoylated versions of B5 and/or lacking most of the cytoplasmic tail were isolated and characterized. Cell-to-cell virus transmission and extracellular virus formation were only slightly affected by those mutations. Notably, B5 versions lacking palmitate showed decreased interactions with proteins A33 and F13, but were still incorporated into the virus envelope. Expression of mutated B5 by transfection into uninfected cells showed that both the cytoplasmic tail and palmitate have a role in the intracellular transport of B5. These results indicate that the C-terminal portion of protein B5, while involved in protein transport and in protein–protein interactions, is broadly dispensable for the formation and egress of infectious extracellular virus and for virus transmission.

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de Sousa-d’Auria, Célia, Florence Constantinesco-Becker, Patricia Constant, Maryelle Tropis, and Christine Houssin. "Genome-wide identification of novel genes involved in Corynebacteriales cell envelope biogenesis using Corynebacterium glutamicum as a model." PLOS ONE 15, no. 12 (December 31, 2020): e0240497. http://dx.doi.org/10.1371/journal.pone.0240497.

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Corynebacteriales are Actinobacteria that possess an atypical didermic cell envelope. One of the principal features of this cell envelope is the presence of a large complex made up of peptidoglycan, arabinogalactan and mycolic acids. This covalent complex constitutes the backbone of the cell wall and supports an outer membrane, called mycomembrane in reference to the mycolic acids that are its major component. The biosynthesis of the cell envelope of Corynebacteriales has been extensively studied, in particular because it is crucial for the survival of important pathogens such as Mycobacterium tuberculosis and is therefore a key target for anti-tuberculosis drugs. In this study, we explore the biogenesis of the cell envelope of Corynebacterium glutamicum, a non-pathogenic Corynebacteriales, which can tolerate dramatic modifications of its cell envelope as important as the loss of its mycomembrane. For this purpose, we used a genetic approach based on genome-wide transposon mutagenesis. We developed a highly effective immunological test based on the use of anti-cell wall antibodies that allowed us to rapidly identify bacteria exhibiting an altered cell envelope. A very large number (10,073) of insertional mutants were screened by means of this test, and 80 were finally selected, representing 55 different loci. Bioinformatics analyses of these loci showed that approximately 60% corresponded to genes already characterized, 63% of which are known to be directly involved in cell wall processes, and more specifically in the biosynthesis of the mycoloyl-arabinogalactan-peptidoglycan complex. We identified 22 new loci potentially involved in cell envelope biogenesis, 76% of which encode putative cell envelope proteins. A mutant of particular interest was further characterized and revealed a new player in mycolic acid metabolism. Because a large proportion of the genes identified by our study is conserved in Corynebacteriales, the library described here provides a new resource of genes whose characterization could lead to a better understanding of the biosynthesis of the envelope components of these bacteria.

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Sauer, Joshua B., Owen N. Vickery, Keith Cassidy, Robin A. Corey, and Phillip J. Stansfeld. "Molecular Simulations of Biogenesis Processes within the Bacterial Cell Envelope." Biophysical Journal 120, no. 3 (February 2021): 49a. http://dx.doi.org/10.1016/j.bpj.2020.11.536.

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Morré, D. James, Jeffrey T. Morré, Susan R. Morré, Christer Sundqvist, and Anna Stina Sandelius. "Chloroplast biogenesis. Cell-free transfer of envelope monogalactosylglycerides to thylakoids." Biochimica et Biophysica Acta (BBA) - Biomembranes 1070, no. 2 (December 1991): 437–45. http://dx.doi.org/10.1016/0005-2736(91)90084-l.

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Steenhuis, Maurice, Corinne M. ten Hagen-Jongman, Peter van Ulsen, and Joen Luirink. "Stress-Based High-Throughput Screening Assays to Identify Inhibitors of Cell Envelope Biogenesis." Antibiotics 9, no. 11 (November 13, 2020): 808. http://dx.doi.org/10.3390/antibiotics9110808.

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The structural integrity of the Gram-negative cell envelope is guarded by several stress responses, such as the σE, Cpx and Rcs systems. Here, we report on assays that monitor these responses in E. coli upon addition of antibacterial compounds. Interestingly, compromised peptidoglycan synthesis, outer membrane biogenesis and LPS integrity predominantly activated the Rcs response, which we developed into a robust HTS (high-throughput screening) assay that is suited for phenotypic compound screening. Furthermore, by interrogating all three cell envelope stress reporters, and a reporter for the cytosolic heat-shock response as control, we found that inhibitors of specific envelope targets induce stress reporter profiles that are distinct in quality, amplitude and kinetics. Finally, we show that by using a host strain with a more permeable outer membrane, large-scaffold antibiotics can also be identified by the reporter assays. Together, the data suggest that stress profiling is a useful first filter for HTS aimed at inhibitors of cell envelope processes.

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Marelli, Marcello, C. Patrick Lusk, Honey Chan, John D. Aitchison, and Richard W. Wozniak. "A Link between the Synthesis of Nucleoporins and the Biogenesis of the Nuclear Envelope." Journal of Cell Biology 153, no. 4 (May 7, 2001): 709–24. http://dx.doi.org/10.1083/jcb.153.4.709.

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The nuclear pore complex (NPC) is a multicomponent structure containing a subset of proteins that bind nuclear transport factors or karyopherins and mediate their movement across the nuclear envelope. By altering the expression of a single nucleoporin gene, NUP53, we showed that the overproduction of Nup53p altered nuclear transport and had a profound effect on the structure of the nuclear membrane. Strikingly, conventional and immunoelectron microscopy analysis revealed that excess Nup53p entered the nucleus and associated with the nuclear membrane. Here, Nup53p induced the formation of intranuclear, tubular membranes that later formed flattened, double membrane lamellae structurally similar to the nuclear envelope. Like the nuclear envelope, the intranuclear double membrane lamellae enclosed a defined cisterna that was interrupted by pores but, unlike the nuclear envelope pores, they lacked NPCs. Consistent with this observation, we detected only two NPC proteins, the pore membrane proteins Pom152p and Ndc1p, in association with these membrane structures. Thus, these pores likely represent an intermediate in NPC assembly. We also demonstrated that the targeting of excess Nup53p to the NPC and its specific association with intranuclear membranes were dependent on the karyopherin Kap121p and the nucleoporin Nup170p. At the nuclear envelope, the abilities of Nup53p to associate with the membrane and drive membrane proliferation were dependent on a COOH-terminal segment containing a potential amphipathic α-helix. The implications of these results with regards to the biogenesis of the nuclear envelope are discussed.

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Barbosa, Antonio Daniel, Hiroshi Sembongi, Wen-Min Su, Susana Abreu, Fulvio Reggiori, George M. Carman, and Symeon Siniossoglou. "Lipid partitioning at the nuclear envelope controls membrane biogenesis." Molecular Biology of the Cell 26, no. 20 (October 15, 2015): 3641–57. http://dx.doi.org/10.1091/mbc.e15-03-0173.

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Partitioning of lipid precursors between membranes and storage is crucial for cell growth, and its disruption underlies pathologies such as cancer, obesity, and type 2 diabetes. However, the mechanisms and signals that regulate this process are largely unknown. In yeast, lipid precursors are mainly used for phospholipid synthesis in nutrient-rich conditions in order to sustain rapid proliferation but are redirected to triacylglycerol (TAG) stored in lipid droplets during starvation. Here we investigate how cells reprogram lipid metabolism in the endoplasmic reticulum. We show that the conserved phosphatidate (PA) phosphatase Pah1, which generates diacylglycerol from PA, targets a nuclear membrane subdomain that is in contact with growing lipid droplets and mediates TAG synthesis. We find that cytosol acidification activates the master regulator of Pah1, the Nem1-Spo7 complex, thus linking Pah1 activity to cellular metabolic status. In the absence of TAG storage capacity, Pah1 still binds the nuclear membrane, but lipid precursors are redirected toward phospholipids, resulting in nuclear deformation and a proliferation of endoplasmic reticulum membrane. We propose that, in response to growth signals, activation of Pah1 at the nuclear envelope acts as a switch to control the balance between membrane biogenesis and lipid storage.

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Chadrin, Anne, Barbara Hess, Mabel San Roman, Xavier Gatti, Bérangère Lombard, Damarys Loew, Yves Barral, Benoit Palancade, and Valérie Doye. "Pom33, a novel transmembrane nucleoporin required for proper nuclear pore complex distribution." Journal of Cell Biology 189, no. 5 (May 24, 2010): 795–811. http://dx.doi.org/10.1083/jcb.200910043.

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The biogenesis of nuclear pore complexes (NPCs) represents a paradigm for the assembly of high-complexity macromolecular structures. So far, only three integral pore membrane proteins are known to function redundantly in NPC anchoring within the nuclear envelope. Here, we describe the identification and functional characterization of Pom33, a novel transmembrane protein dynamically associated with budding yeast NPCs. Pom33 becomes critical for yeast viability in the absence of a functional Nup84 complex or Ndc1 interaction network, which are two core NPC subcomplexes, and associates with the reticulon Rtn1. Moreover, POM33 loss of function impairs NPC distribution, a readout for a subset of genes required for pore biogenesis, including members of the Nup84 complex and RTN1. Consistently, we show that Pom33 is required for normal NPC density in the daughter nucleus and for proper NPC biogenesis and/or stability in the absence of Nup170. We hypothesize that, by modifying or stabilizing the nuclear envelope–NPC interface, Pom33 may contribute to proper distribution and/or efficient assembly of nuclear pores.

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Braun, Martin, and Thomas J. Silhavy. "Imp/OstA is required for cell envelope biogenesis in Escherichia coli." Molecular Microbiology 45, no. 5 (September 2, 2002): 1289–302. http://dx.doi.org/10.1046/j.1365-2958.2002.03091.x.

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Zhang, Wanlu, Annett Neuner, Diana Rüthnick, Timo Sachsenheimer, Christian Lüchtenborg, Britta Brügger, and Elmar Schiebel. "Brr6 and Brl1 locate to nuclear pore complex assembly sites to promote their biogenesis." Journal of Cell Biology 217, no. 3 (February 9, 2018): 877–94. http://dx.doi.org/10.1083/jcb.201706024.

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The paralogous Brr6 and Brl1 are conserved integral membrane proteins of the nuclear envelope (NE) with an unclear role in nuclear pore complex (NPC) biogenesis. Here, we analyzed double-degron mutants of Brr6/Brl1 to understand this function. Depletion of Brr6 and Brl1 caused defects in NPC biogenesis, whereas the already assembled NPCs remained unaffected. This NPC biogenesis defect was not accompanied by a change in lipid composition. However, Brl1 interacted with Ndc1 and Nup188 by immunoprecipitation, and with transmembrane and outer and inner ring NPC components by split yellow fluorescent protein analysis, indicating a direct role in NPC biogenesis. Consistently, we found that Brr6 and Brl1 associated with a subpopulation of NPCs and emerging NPC assembly sites. Moreover, BRL1 overexpression affected NE morphology without a change in lipid composition and completely suppressed the nuclear pore biogenesis defect of nup116Δ and gle2Δ cells. We propose that Brr6 and Brl1 transiently associate with NPC assembly sites where they promote NPC biogenesis.

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Goodall, Emily C. A., Georgia L. Isom, Jessica L. Rooke, Karthik Pullela, Christopher Icke, Zihao Yang, Gabriela Boelter, et al. "Loss of YhcB results in dysregulation of coordinated peptidoglycan, LPS and phospholipid synthesis during Escherichia coli cell growth." PLOS Genetics 17, no. 12 (December 23, 2021): e1009586. http://dx.doi.org/10.1371/journal.pgen.1009586.

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The cell envelope is essential for viability in all domains of life. It retains enzymes and substrates within a confined space while providing a protective barrier to the external environment. Destabilising the envelope of bacterial pathogens is a common strategy employed by antimicrobial treatment. However, even in one of the best studied organisms, Escherichia coli, there remain gaps in our understanding of how the synthesis of the successive layers of the cell envelope are coordinated during growth and cell division. Here, we used a whole-genome phenotypic screen to identify mutants with a defective cell envelope. We report that loss of yhcB, a conserved gene of unknown function, results in loss of envelope stability, increased cell permeability and dysregulated control of cell size. Using whole genome transposon mutagenesis strategies, we report the comprehensive genetic interaction network of yhcB, revealing all genes with a synthetic negative and a synthetic positive relationship. These genes include those previously reported to have a role in cell envelope biogenesis. Surprisingly, we identified genes previously annotated as essential that became non-essential in a ΔyhcB background. Subsequent analyses suggest that YhcB functions at the junction of several envelope biosynthetic pathways coordinating the spatiotemporal growth of the cell, highlighting YhcB as an as yet unexplored antimicrobial target.

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Aitchison, Adam J., Daniel J. Arsenault, and Neale D. Ridgway. "Nuclear-localized CTP:phosphocholine cytidylyltransferase α regulates phosphatidylcholine synthesis required for lipid droplet biogenesis." Molecular Biology of the Cell 26, no. 16 (August 15, 2015): 2927–38. http://dx.doi.org/10.1091/mbc.e15-03-0159.

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The reversible association of CTP:phosphocholine cytidylyltransferase α (CCTα) with membranes regulates the synthesis of phosphatidylcholine (PC) by the CDP-choline (Kennedy) pathway. Based on results with insect CCT homologues, translocation of nuclear CCTα onto cytoplasmic lipid droplets (LDs) is proposed to stimulate the synthesis of PC that is required for LD biogenesis and triacylglycerol (TAG) storage. We examined whether this regulatory mechanism applied to LD biogenesis in mammalian cells. During 3T3-L1 and human preadipocyte differentiation, CCTα expression and PC synthesis was induced. In 3T3-L1 cells, CCTα translocated from the nucleoplasm to the nuclear envelope and cytosol but did not associate with LDs. The enzyme also remained in the nucleus during human adipocyte differentiation. RNAi silencing in 3T3-L1 cells showed that CCTα regulated LD size but did not affect TAG storage or adipogenesis. LD biogenesis in nonadipocyte cell lines treated with oleate also promoted CCTα translocation to the nuclear envelope and/or cytoplasm but not LDs. In rat intestinal epithelial cells, CCTα silencing increased LD size, but LD number and TAG deposition were decreased due to oleate-induced cytotoxicity. We conclude that CCTα increases PC synthesis for LD biogenesis by translocation to the nuclear envelope and not cytoplasmic LDs.

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Zhao, Heng, Yingjie Sun, Jason M. Peters, Carol A. Gross, Ethan C. Garner, and John D. Helmann. "Depletion of Undecaprenyl Pyrophosphate Phosphatases Disrupts Cell Envelope Biogenesis in Bacillus subtilis." Journal of Bacteriology 198, no. 21 (August 15, 2016): 2925–35. http://dx.doi.org/10.1128/jb.00507-16.

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ABSTRACTThe integrity of the bacterial cell envelope is essential to sustain life by countering the high turgor pressure of the cell and providing a barrier against chemical insults. InBacillus subtilis, synthesis of both peptidoglycan and wall teichoic acids requires a common C55lipid carrier, undecaprenyl-pyrophosphate (UPP), to ferry precursors across the cytoplasmic membrane. The synthesis and recycling of UPP requires a phosphatase to generate the monophosphate form Und-P, which is the substrate for peptidoglycan and wall teichoic acid synthases. Using an optimizedclusteredregularlyinterspacedshortpalindromicrepeat (CRISPR) system with catalytically inactive (“dead”)CRISPR-associated protein9(dCas9)-based transcriptional repression system (CRISPR interference [CRISPRi]), we demonstrate thatB. subtilisrequires either of two UPP phosphatases, UppP or BcrC, for viability. We show that a third predicted lipid phosphatase (YodM), with homology to diacylglycerol pyrophosphatases, can also support growth when overexpressed. Depletion of UPP phosphatase activity leads to morphological defects consistent with a failure of cell envelope synthesis and strongly activates the σM-dependent cell envelope stress response, includingbcrC, which encodes one of the two UPP phosphatases. These results highlight the utility of an optimized CRISPRi system for the investigation of synthetic lethal gene pairs, clarify the nature of theB. subtilisUPP-Pase enzymes, and provide further evidence linking the σMregulon to cell envelope homeostasis pathways.IMPORTANCEThe emergence of antibiotic resistance among bacterial pathogens is of critical concern and motivates efforts to develop new therapeutics and increase the utility of those already in use. The lipid II cycle is one of the most frequently targeted processes for antibiotics and has been intensively studied. Despite these efforts, some steps have remained poorly defined, partly due to genetic redundancy. CRISPRi provides a powerful tool to investigate the functions of essential genes and sets of genes. Here, we used an optimized CRISPRi system to demonstrate functional redundancy of two UPP phosphatases that are required for the conversion of the initially synthesized UPP lipid carrier to Und-P, the substrate for the synthesis of the initial lipid-linked precursors in peptidoglycan and wall teichoic acid synthesis.

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Bahmanyar, Shirin, and Christian Schlieker. "Lipid and protein dynamics that shape nuclear envelope identity." Molecular Biology of the Cell 31, no. 13 (June 15, 2020): 1315–23. http://dx.doi.org/10.1091/mbc.e18-10-0636.

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The nuclear envelope (NE) is continuous with the endoplasmic reticulum (ER), yet the NE carries out many functions distinct from those of bulk ER. This functional specialization depends on a unique protein composition that defines NE identity and must be both established and actively maintained. The NE undergoes extensive remodeling in interphase and mitosis, so mechanisms that seal NE holes and protect its unique composition are critical for maintaining its functions. New evidence shows that closure of NE holes relies on regulated de novo lipid synthesis, providing a link between lipid metabolism and generating and maintaining NE identity. Here, we review regulation of the lipid bilayers of the NE and suggest ways to generate lipid asymmetry across the NE despite its direct continuity with the ER. We also discuss the elusive mechanism of membrane fusion during nuclear pore complex (NPC) biogenesis. We propose a model in which NPC biogenesis is carefully controlled to ensure that a permeability barrier has been established before membrane fusion, thereby avoiding a major threat to compartmentalization.

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Badyakina, Alla, Natalia Vasil’eva, Yulia Koryakina, Elena Anisimova, Natalia Suzina, and Marina Nesmeyanova. "The change in membrane phospholipid composition influences protein secretion and cell envelope biogenesis in Escherichia coli." Open Life Sciences 2, no. 3 (September 1, 2007): 385–404. http://dx.doi.org/10.2478/s11535-007-0028-8.

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AbstractSecretion of periplasmic alkaline phosphatase (PhoA) encoded by the gene constituent of plasmids and the peculiar properties of cell envelope biogenesis in Escherichia coli strains with controlled synthesis of individual membrane phospholipids have been studied. Alkaline phosphatase secretion across the cytoplasmic membrane declines, while secretion into the culture medium intensifies under changed metabolism. The composition of anionic membrane phospholipids changes due to inactivation of the pgsA gene or regulation of its expression by environmental factor, as well as in the absence of the pssA gene which is responsible for the synthesis of the precursor for zwitter-ionic phospholipid — phosphatidylethanolamine. This correlates with intensified secretion of exopolysaccharides and lower content of lipopolysaccharide and lipoprotein which are responsible for barrier properties of the outer membrane. The results suggest a possible coupling of protein secretion with biogenesis of cell envelope components at a level of phospholipid metabolism.

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Hayashi, Jennifer M., Chu-Yuan Luo, Jacob A. Mayfield, Tsungda Hsu, Takeshi Fukuda, Andrew L. Walfield, Samantha R. Giffen, et al. "Spatially distinct and metabolically active membrane domain in mycobacteria." Proceedings of the National Academy of Sciences 113, no. 19 (April 25, 2016): 5400–5405. http://dx.doi.org/10.1073/pnas.1525165113.

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Protected from host immune attack and antibiotic penetration by their unique cell envelope, mycobacterial pathogens cause devastating human diseases such as tuberculosis. Seamless coordination of cell growth with cell envelope elongation at the pole maintains this barrier. Unraveling this spatiotemporal regulation is a potential strategy for controlling mycobacterial infections. Our biochemical analysis previously revealed two functionally distinct membrane fractions in Mycobacterium smegmatis cell lysates: plasma membrane tightly associated with the cell wall (PM-CW) and a distinct fraction of pure membrane free of cell wall components (PMf). To provide further insight into the functions of these membrane fractions, we took the approach of comparative proteomics and identified more than 300 proteins specifically associated with the PMf, including essential enzymes involved in cell envelope synthesis such as a mannosyltransferase, Ppm1, and a galactosyltransferase, GlfT2. Furthermore, comparative lipidomics revealed the distinct lipid composition of the PMf, with specific association of key cell envelope biosynthetic precursors. Live-imaging fluorescence microscopy visualized the PMf as patches of membrane spatially distinct from the PM-CW and notably enriched in the pole of the growing cells. Taken together, our study provides the basis for assigning the PMf as a spatiotemporally distinct and metabolically active membrane domain involved in cell envelope biogenesis.

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Gerl, Mathias J., Julio L. Sampaio, Severino Urban, Lucie Kalvodova, Jean-Marc Verbavatz, Beth Binnington, Dirk Lindemann, et al. "Quantitative analysis of the lipidomes of the influenza virus envelope and MDCK cell apical membrane." Journal of Cell Biology 196, no. 2 (January 16, 2012): 213–21. http://dx.doi.org/10.1083/jcb.201108175.

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The influenza virus (IFV) acquires its envelope by budding from host cell plasma membranes. Using quantitative shotgun mass spectrometry, we determined the lipidomes of the host Madin–Darby canine kidney cell, its apical membrane, and the IFV budding from it. We found the apical membrane to be enriched in sphingolipids (SPs) and cholesterol, whereas glycerophospholipids were reduced, and storage lipids were depleted compared with the whole-cell membranes. The virus membrane exhibited a further enrichment of SPs and cholesterol compared with the donor membrane at the expense of phosphatidylcholines. Our data are consistent with and extend existing models of membrane raft-based biogenesis of the apical membrane and IFV envelope.

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Rodriguez-Rivera, Frances P., Xiaoxue Zhou, Julie A. Theriot, and Carolyn R. Bertozzi. "Acute Modulation of Mycobacterial Cell Envelope Biogenesis by Front-Line Tuberculosis Drugs." Angewandte Chemie 130, no. 19 (April 14, 2018): 5365–70. http://dx.doi.org/10.1002/ange.201712020.

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Rodriguez-Rivera, Frances P., Xiaoxue Zhou, Julie A. Theriot, and Carolyn R. Bertozzi. "Acute Modulation of Mycobacterial Cell Envelope Biogenesis by Front-Line Tuberculosis Drugs." Angewandte Chemie International Edition 57, no. 19 (April 14, 2018): 5267–72. http://dx.doi.org/10.1002/anie.201712020.

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Graham, Chris L. B., Hector Newman, Francesca N. Gillett, Katie Smart, Nicholas Briggs, Manuel Banzhaf, and David I. Roper. "A Dynamic Network of Proteins Facilitate Cell Envelope Biogenesis in Gram-Negative Bacteria." International Journal of Molecular Sciences 22, no. 23 (November 27, 2021): 12831. http://dx.doi.org/10.3390/ijms222312831.

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Bacteria must maintain the ability to modify and repair the peptidoglycan layer without jeopardising its essential functions in cell shape, cellular integrity and intermolecular interactions. A range of new experimental techniques is bringing an advanced understanding of how bacteria regulate and achieve peptidoglycan synthesis, particularly in respect of the central role played by complexes of Sporulation, Elongation or Division (SEDs) and class B penicillin-binding proteins required for cell division, growth and shape. In this review we highlight relationships implicated by a bioinformatic approach between the outer membrane, cytoskeletal components, periplasmic control proteins, and cell elongation/division proteins to provide further perspective on the interactions of these cell division, growth and shape complexes. We detail the network of protein interactions that assist in the formation of peptidoglycan and highlight the increasingly dynamic and connected set of protein machinery and macrostructures that assist in creating the cell envelope layers in Gram-negative bacteria.

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Evans, David E., and Chris Hawes. "Organelle Biogenesis and Positioning in Plants." Biochemical Society Transactions 38, no. 3 (May 24, 2010): 729–32. http://dx.doi.org/10.1042/bst0380729.

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The biogenesis and positioning of organelles involves complex interacting processes and precise control. Progress in our understanding is being made rapidly as advances in analysing the nuclear and organellar genome and proteome combine with developments in live-cell microscopy and manipulation at the subcellular level. This paper introduces the collected papers resulting from Organelle Biogenesis and Positioning in Plants, the 2009 Biochemical Society Annual Symposium. Including papers on the nuclear envelope and all major organelles, it considers current knowledge and progress towards unifying themes that will elucidate the mechanisms by which cells generate the correct complement of organelles and adapt and change it in response to environmental and developmental signals.

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Martínez-Salazar, Jaime M., Emmanuel Salazar, Sergio Encarnación, Miguel A. Ramírez-Romero, and Javier Rivera. "Role of the Extracytoplasmic Function Sigma Factor RpoE4 in Oxidative and Osmotic Stress Responses in Rhizobium etli." Journal of Bacteriology 191, no. 13 (April 17, 2009): 4122–32. http://dx.doi.org/10.1128/jb.01626-08.

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ABSTRACT The aims of this study were to functionally characterize and analyze the transcriptional regulation and transcriptome of the Rhizobium etli rpoE4 gene. An R. etli rpoE4 mutant was sensitive to oxidative, saline, and osmotic stresses. Using transcriptional fusions, we determined that RpoE4 controls its own transcription and that it is negatively regulated by rseF (regulator of sigma rpoE4; CH03274), which is cotranscribed with rpoE4. rpoE4 expression was induced not only after oxidative, saline, and osmotic shocks, but also under microaerobic and stationary-phase growth conditions. The transcriptome analyses of an rpoE4 mutant and an rpoE4-overexpressing strain revealed that the RpoE4 extracytoplasmic function sigma factor regulates about 98 genes; 50 of them have the rpoE4 promoter motifs in the upstream regulatory regions. Interestingly, 16 of 38 genes upregulated in the rpoE4-overexpressing strain encode unknown putative cell envelope proteins. Other genes controlled by RpoE4 include rpoH2, CH00462, CH02434, CH03474, and xthA1, which encode proteins involved in the stress response (a heat shock sigma factor, a putative Mn-catalase, an alkylation DNA repair protein, pyridoxine phosphate oxidase, and exonuclease III, respectively), as well as several genes, such as CH01253, CH03555, and PF00247, encoding putative proteins involved in cell envelope biogenesis (a putative peptidoglycan binding protein, a cell wall degradation protein, and phospholipase D, respectively). These results suggest that rpoE4 has a relevant function in cell envelope biogenesis and that it plays a role as a general regulator in the responses to several kinds of stress.

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Zhang, Ge, Vadim Baidin, Karanbir S. Pahil, Eileen Moison, David Tomasek, Nitya S. Ramadoss, Arnab K. Chatterjee, et al. "Cell-based screen for discovering lipopolysaccharide biogenesis inhibitors." Proceedings of the National Academy of Sciences 115, no. 26 (May 7, 2018): 6834–39. http://dx.doi.org/10.1073/pnas.1804670115.

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New drugs are needed to treat gram-negative bacterial infections. These bacteria are protected by an outer membrane which prevents many antibiotics from reaching their cellular targets. The outer leaflet of the outer membrane contains LPS, which is responsible for creating this permeability barrier. Interfering with LPS biogenesis affects bacterial viability. We developed a cell-based screen that identifies inhibitors of LPS biosynthesis and transport by exploiting the nonessentiality of this pathway inAcinetobacter. We used this screen to find an inhibitor of MsbA, an ATP-dependent flippase that translocates LPS across the inner membrane. Treatment with the inhibitor caused mislocalization of LPS to the cell interior. The discovery of an MsbA inhibitor, which is universally conserved in all gram-negative bacteria, validates MsbA as an antibacterial target. Because our cell-based screen reports on the function of the entire LPS biogenesis pathway, it could be used to identify compounds that inhibit other targets in the pathway, which can provide insights into vulnerabilities of the gram-negative cell envelope.

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Agnihothram, Sudhakar S., Joanne York, and Jack H. Nunberg. "Role of the Stable Signal Peptide and Cytoplasmic Domain of G2 in Regulating Intracellular Transport of the Junín Virus Envelope Glycoprotein Complex." Journal of Virology 80, no. 11 (June 1, 2006): 5189–98. http://dx.doi.org/10.1128/jvi.00208-06.

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ABSTRACT Enveloped viruses utilize the membranous compartments of the host cell for the assembly and budding of new virion particles. In this report, we have investigated the biogenesis and trafficking of the envelope glycoprotein (GP-C) of the Junín arenavirus. The mature GP-C complex is unusual in that it retains a stable signal peptide (SSP) as an essential component in association with the typical receptor-binding (G1) and transmembrane fusion (G2) subunits. We demonstrate that, in the absence of SSP, the G1-G2 precursor is restricted to the endoplasmic reticulum (ER). This constraint is relieved by coexpression of SSP in trans, allowing transit of the assembled GP-C complex through the Golgi and to the cell surface, the site of arenavirus budding. Transport of a chimeric CD4 glycoprotein bearing the transmembrane and cytoplasmic domains of G2 is similarly regulated by SSP association. Truncations to the cytoplasmic domain of G2 abrogate SSP association yet now permit transport of the G1-G2 precursor to the cell surface. Thus, the cytoplasmic domain of G2 is an important determinant for both ER localization and its control through SSP binding. Alanine mutations to either of two dibasic amino acid motifs in the G2 cytoplasmic domain can also mobilize the G1-G2 precursor for transit through the Golgi. Taken together, our results suggest that SSP binding masks endogenous ER localization signals in the cytoplasmic domain of G2 to ensure that only the fully assembled, tripartite GP-C complex is transported for virion assembly. This quality control process points to an important role of SSP in the structure and function of the arenavirus envelope glycoprotein.

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Li, Ming, and Danny J. Schnell. "Reconstitution of protein targeting to the inner envelope membrane of chloroplasts." Journal of Cell Biology 175, no. 2 (October 23, 2006): 249–59. http://dx.doi.org/10.1083/jcb.200605162.

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The chloroplast envelope plays critical roles in the synthesis and regulated transport of key metabolites, including intermediates in photosynthesis and lipid metabolism. Despite this importance, the biogenesis of the envelope membranes has not been investigated in detail. To identify the determinants of protein targeting to the inner envelope membrane (IM), we investigated the targeting of the nucleus-encoded integral IM protein, atTic40. We found that pre-atTic40 is imported into chloroplasts and processed to an intermediate size (int-atTic40) before insertion into the IM. Int-atTic40 is soluble and inserts into the IM from the internal stromal compartment. We also show that atTic40 and a second IM protein, atTic110, can target and insert into isolated IM vesicles in vitro. Collectively, our experiments are consistent with a “postimport” mechanism in which the IM proteins are first imported from the cytoplasm and subsequently inserted into the IM from the stroma.

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Hu, Bo, Pratick Khara, and Peter J. Christie. "Structural bases for F plasmid conjugation and F pilus biogenesis inEscherichia coli." Proceedings of the National Academy of Sciences 116, no. 28 (June 25, 2019): 14222–27. http://dx.doi.org/10.1073/pnas.1904428116.

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Bacterial conjugation systems are members of the large type IV secretion system (T4SS) superfamily. Conjugative transfer of F plasmids residing in theEnterobacteriaceaewas first reported in the 1940s, yet the architecture of F plasmid-encoded transfer channel and its physical relationship with the F pilus remain unknown. We visualized F-encoded structures in the native bacterial cell envelope by in situ cryoelectron tomography (CryoET). Remarkably, F plasmids encode four distinct structures, not just the translocation channel or channel-pilus complex predicted by prevailing models. The F1 structure is composed of distinct outer and inner membrane complexes and a connecting cylinder that together house the envelope-spanning translocation channel. The F2 structure is essentially the F1 complex with the F pilus attached at the outer membrane (OM). Remarkably, the F3 structure consists of the F pilus attached to a thin, cell envelope-spanning stalk, whereas the F4 structure consists of the pilus docked to the OM without an associated periplasmic density. The traffic ATPase TraC is configured as a hexamer of dimers at the cytoplasmic faces of the F1 and F2 structures, where it respectively regulates substrate transfer and F pilus biogenesis. Together, our findings present architectural renderings of the DNA conjugation or “mating” channel, the channel–pilus connection, and unprecedented pilus basal structures. These structural snapshots support a model for biogenesis of the F transfer system and allow for detailed comparisons with other structurally characterized T4SSs.

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Scarcelli, John J., Christine A. Hodge, and Charles N. Cole. "The yeast integral membrane protein Apq12 potentially links membrane dynamics to assembly of nuclear pore complexes." Journal of Cell Biology 178, no. 5 (August 27, 2007): 799–812. http://dx.doi.org/10.1083/jcb.200702120.

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Although the structure and function of components of the nuclear pore complex (NPC) have been the focus of many studies, relatively little is known about NPC biogenesis. In this study, we report that Apq12 is required for efficient NPC biogenesis in Saccharomyces cerevisiae. Apq12 is an integral membrane protein of the nuclear envelope (NE) and endoplasmic reticulum. Cells lacking Apq12 are cold sensitive for growth, and a subset of their nucleoporins (Nups), those that are primarily components of the cytoplasmic fibrils of the NPC, mislocalize to the cytoplasm. APQ12 deletion also causes defects in NE morphology. In the absence of Apq12, most NPCs appear to be associated with the inner but not the outer nuclear membrane. Low levels of benzyl alcohol, which increases membrane fluidity, prevented Nup mislocalization and restored the proper localization of Nups that had accumulated in cytoplasmic foci upon a shift to lower temperature. Thus, Apq12p connects nuclear pore biogenesis to the dynamics of the NE.

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Maréchal, E., K. Awai, M. A. Block, D. Brun, T. Masuda, H. Shimada, K. i. Takamiya, H. Ohta, and J. Joyard. "The multigenic family of monogalactosyl diacylglycerol synthases." Biochemical Society Transactions 28, no. 6 (December 1, 2000): 732–38. http://dx.doi.org/10.1042/bst0280732.

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Because the synthesis of monogalactosyldiacylglycerol (MGDG) is unique to plants, identified as an important marker of the plastid envelope, involved in a key step of plastid biogenesis and is the most abundant lipid on earth, MGDG synthase activity was extensively analysed at the biochemical and physiological levels. In the present paper, we present our current knowledge on the MGDG synthase's function, structure and topology in envelope membranes, and discuss possible roles in plant cell glycerolipid metabolism. The recent discovery of a multigenic family of MGDG synthases raised the possibility that multiple isoenzymes might carry out MGDG synthesis in various tissues and developmental stages.

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McKnight, Kevin L., Ling Xie, Olga González-López, Efraín E. Rivera-Serrano, Xian Chen, and Stanley M. Lemon. "Protein composition of the hepatitis A virus quasi-envelope." Proceedings of the National Academy of Sciences 114, no. 25 (May 10, 2017): 6587–92. http://dx.doi.org/10.1073/pnas.1619519114.

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The Picornaviridae are a diverse family of RNA viruses including many pathogens of medical and veterinary importance. Classically considered “nonenveloped,” recent studies show that some picornaviruses, notably hepatitis A virus (HAV; genus Hepatovirus) and some members of the Enterovirus genus, are released from cells nonlytically in membranous vesicles. To better understand the biogenesis of quasi-enveloped HAV (eHAV) virions, we conducted a quantitative proteomics analysis of eHAV purified from cell-culture supernatant fluids by isopycnic ultracentrifugation. Amino acid-coded mass tagging (AACT) with stable isotopes followed by tandem mass spectrometry sequencing and AACT quantitation of peptides provided unambiguous identification of proteins associated with eHAV versus unrelated extracellular vesicles with similar buoyant density. Multiple peptides were identified from HAV capsid proteins (53.7% coverage), but none from nonstructural proteins, indicating capsids are packaged as cargo into eHAV vesicles via a highly specific sorting process. Other eHAV-associated proteins (n = 105) were significantly enriched for components of the endolysosomal system (>60%, P < 0.001) and included many common exosome-associated proteins such as the tetraspanin CD9 and dipeptidyl peptidase 4 (DPP4) along with multiple endosomal sorting complex required for transport III (ESCRT-III)-associated proteins. Immunoprecipitation confirmed that DPP4 is displayed on the surface of eHAV produced in cell culture or present in sera from humans with acute hepatitis A. No LC3-related peptides were identified by mass spectrometry. RNAi depletion studies confirmed that ESCRT-III proteins, particularly CHMP2A, function in eHAV biogenesis. In addition to identifying surface markers of eHAV vesicles, the results support an exosome-like mechanism of eHAV egress involving endosomal budding of HAV capsids into multivesicular bodies.

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Li, Gaochi, Kentaro Hamamoto, and Madoka Kitakawa. "Inner Membrane Protein YhcB Interacts with RodZ Involved in Cell Shape Maintenance in Escherichia coli." ISRN Molecular Biology 2012 (September 3, 2012): 1–8. http://dx.doi.org/10.5402/2012/304021.

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Depletion of YhcB, an inner membrane protein of Escherichia coli, inhibited the growth of rodZ deletion mutant showing that the loss of both YhcB and RodZ is synthetically lethal. Furthermore, YhcB was demonstrated to interact with RodZ as well as several other proteins involved in cell shape maintenance and an inner membrane protein YciS of unknown function, using bacterial two-hybrid system. These observations seem to indicate that YhcB is involved in the biogenesis of cell envelope and the maintenance of cell shape together with RodZ.

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Shen, Juan, Tianpeng Li, Xiaojia Niu, Wenyue Liu, Shengnan Zheng, Jing Wang, Fengsong Wang, et al. "The J-domain cochaperone Rsp1 interacts with Mto1 to organize noncentrosomal microtubule assembly." Molecular Biology of the Cell 30, no. 2 (January 15, 2019): 256–67. http://dx.doi.org/10.1091/mbc.e18-05-0279.

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Microtubule biogenesis initiates at various intracellular sites, including the centrosome, the Golgi apparatus, the nuclear envelope, and preexisting microtubules. Similarly, in the fission yeast Schizosaccharomyces pombe, interphase microtubules are nucleated at the spindle pole body (SPB), the nuclear envelope, and preexisting microtubules, depending on Mto1 activity. Despite the essential role of Mto1 in promoting microtubule nucleation, how distribution of Mto1 in different sites is regulated has remained elusive. Here, we show that the J-domain cochaperone Rsp1 interacts with Mto1 and specifies the localization of Mto1 to non-SPB nucleation sites. The absence of Rsp1 abolishes the localization of Mto1 to non-SPB nucleation sites, with concomitant enrichment of Mto1 to the SPB and the nuclear envelope. In contrast, Rsp1 overexpression impairs the localization of Mto1 to all microtubule organization sites. These findings delineate a previously uncharacterized mechanism in which Rsp1-Mto1 interaction orchestrates non-SPB microtubule formation.

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Melly, Geoff C., Haley Stokas, Jennifer L. Dunaj, Fong Fu Hsu, Malligarjunan Rajavel, Chih-Chia Su, Edward W. Yu, and Georgiana E. Purdy. "Structural and functional evidence that lipoprotein LpqN supports cell envelope biogenesis in Mycobacterium tuberculosis." Journal of Biological Chemistry 294, no. 43 (August 30, 2019): 15711–23. http://dx.doi.org/10.1074/jbc.ra119.008781.

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Babu, Mohan, J. Javier Díaz-Mejía, James Vlasblom, Alla Gagarinova, Sadhna Phanse, Chris Graham, Fouad Yousif, et al. "Genetic Interaction Maps in Escherichia coli Reveal Functional Crosstalk among Cell Envelope Biogenesis Pathways." PLoS Genetics 7, no. 11 (November 17, 2011): e1002377. http://dx.doi.org/10.1371/journal.pgen.1002377.

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Nayar, Asha S., Thomas J. Dougherty, Keith E. Ferguson, Brett A. Granger, Lisa McWilliams, Clare Stacey, Lindsey J. Leach, et al. "Novel Antibacterial Targets and Compounds Revealed by a High-Throughput Cell Wall Reporter Assay." Journal of Bacteriology 197, no. 10 (March 2, 2015): 1726–34. http://dx.doi.org/10.1128/jb.02552-14.

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ABSTRACTA high-throughput phenotypic screen based on aCitrobacter freundiiAmpC reporter expressed inEscherichia coliwas executed to discover novel inhibitors of bacterial cell wall synthesis, an attractive, well-validated target for antibiotic intervention. Here we describe the discovery and characterization of sulfonyl piperazine and pyrazole compounds, each with novel mechanisms of action.E. colimutants resistant to these compounds display no cross-resistance to antibiotics of other classes. Resistance to the sulfonyl piperazine maps to LpxH, which catalyzes the fourth step in the synthesis of lipid A, the outer membrane anchor of lipopolysaccharide (LPS). To our knowledge, this compound is the first reported inhibitor of LpxH. Resistance to the pyrazole compound mapped to mutations in either LolC or LolE, components of the essential LolCDE transporter complex, which is required for trafficking of lipoproteins to the outer membrane. Biochemical experiments withE. colispheroplasts showed that the pyrazole compound is capable of inhibiting the release of lipoproteins from the inner membrane. Both of these compounds have significant promise as chemical probes to further interrogate the potential of these novel cell wall components for antimicrobial therapy.IMPORTANCEThe prevalence of antibacterial resistance, particularly among Gram-negative organisms, signals a need for novel antibacterial agents. A phenotypic screen using AmpC as a sensor for compounds that inhibit processes involved in Gram-negative envelope biogenesis led to the identification of two novel inhibitors with unique mechanisms of action targetingEscherichia coliouter membrane biogenesis. One compound inhibits the transport system for lipoprotein transport to the outer membrane, while the other compound inhibits synthesis of lipopolysaccharide. These results indicate that it is still possible to uncover new compounds with intrinsic antibacterial activity that inhibit novel targets related to the cell envelope, suggesting that the Gram-negative cell envelope still has untapped potential for therapeutic intervention.

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Becker, Thomas, Jozef Hritz, Markus Vogel, Alexander Caliebe, Bernd Bukau, Jürgen Soll, and Enrico Schleiff. "Toc12, a Novel Subunit of the Intermembrane Space Preprotein Translocon of Chloroplasts." Molecular Biology of the Cell 15, no. 11 (November 2004): 5130–44. http://dx.doi.org/10.1091/mbc.e04-05-0405.

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Translocation of proteins across membranes is essential for the biogenesis of each cell and is achieved by proteinaceous complexes. We analyzed the translocation complex of the intermembrane space from chloroplasts and identified a 12-kDa protein associated with the Toc machinery. Toc12 is an outer envelope protein exposing a soluble domain into the intermembrane space. Toc12 contains a J-domain and stimulates the ATPase activity of DnaK. The conformational stability and the ability to stimulate Hsp70 are dependent on a disulfide bridge within the loop region of the J-domain, suggesting a redox-regulated activation of the chaperone. Toc12 is associated with Toc64 and Tic22. Its J-domain recruits the Hsp70 of outer envelope membrane to the intermembrane space translocon and facilitates its interaction to the preprotein.

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Shah, Pramod, and Chien-Sheng Chen. "Systematic Screening of Penetratin’s Protein Targets by Yeast Proteome Microarrays." International Journal of Molecular Sciences 23, no. 2 (January 10, 2022): 712. http://dx.doi.org/10.3390/ijms23020712.

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Cell-penetrating peptides (CPPs) have distinct properties to translocate across cell envelope. The key property of CPPs to translocation with attached molecules has been utilized as vehicles for the delivery of several potential drug candidates that illustrate the significant effect in in-vitro experiment but fail in in-vivo experiment due to selectively permeable nature of cell envelop. Penetratin, a well-known CPP identified from the third α-helix of Antennapedia homeodomain of Drosophila, has been widely used and studied for the delivery of bioactive molecules to treat cancers, stroke, and infections caused by pathogenic organisms. Few studies have demonstrated that penetratin directly possesses antimicrobial activities against bacterial and fungal pathogens; however, the mechanism is unknown. In this study, we have utilized the power of high-throughput Saccharomyces cerevisiae proteome microarrays to screen all the potential protein targets of penetratin. Saccharomyces cerevisiae proteome microarrays assays of penetratin followed by statistical analysis depicted 123 Saccharomyces cerevisiae proteins as the protein targets of penetratin out of ~5800 Saccharomyces cerevisiae proteins. To understand the target patterns of penetratin, enrichment analyses were conducted using 123 protein targets. In biological process: ribonucleoprotein complex biogenesis, nucleic acid metabolic process, actin filament-based process, transcription, DNA-templated, and negative regulation of gene expression are a few significantly enriched terms. Cytoplasm, nucleus, and cell-organelles are enriched terms for cellular component. Protein-protein interactions network depicted ribonucleoprotein complex biogenesis, cortical cytoskeleton, and histone binding, which represent the major enriched terms for the 123 protein targets of penetratin. We also compared the protein targets of penetratin and intracellular protein targets of antifungal AMPs (Lfcin B, Histatin-5, and Sub-5). The comparison results showed few unique proteins between penetratin and AMPs. Nucleic acid metabolic process and cellular component disassembly were the common enrichment terms for penetratin and three AMPs. Penetratin shows unique enrichment items that are related to DNA biological process. Moreover, motif enrichment analysis depicted different enriched motifs in the protein targets of penetratin, LfcinB, Histatin-5, and Sub-5.

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Liu, Fangfang, Seng Kah Ng, Yanfen Lu, Wilson Low, Julian Lai, and Gregory Jedd. "Making two organelles from one: Woronin body biogenesis by peroxisomal protein sorting." Journal of Cell Biology 180, no. 2 (January 28, 2008): 325–39. http://dx.doi.org/10.1083/jcb.200705049.

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Woronin bodies (WBs) are dense-core organelles that are found exclusively in filamentous fungi and that seal the septal pore in response to wounding. These organelles consist of a membrane-bound protein matrix comprised of the HEX protein and, although they form from peroxisomes, their biogenesis is poorly understood. In Neurospora crassa, we identify Woronin sorting complex (WSC), a PMP22/MPV17-related membrane protein with dual functions in WB biogenesis. WSC localizes to large peroxisome membranes where it self-assembles into detergent-resistant oligomers that envelop HEX assemblies, producing asymmetrical nascent WBs. In a reaction requiring WSC, these structures are delivered to the cell cortex, which permits partitioning of the nascent WB and WB inheritance. Our findings suggest that WSC and HEX collaborate and control distinct aspects of WB biogenesis and that cortical association depends on WSC, which in turn depends on HEX. This dependency helps order events across the organellar membrane, permitting the peroxisome to produce a second organelle with a distinct composition and intracellular distribution.

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Jarvis, Michael A., Kenneth N. Fish, Cecilia Söderberg-Naucler, Daniel N. Streblow, Heather L. Meyers, Gary Thomas, and Jay A. Nelson. "Retrieval of Human Cytomegalovirus Glycoprotein B from Cell Surface Is Not Required for Virus Envelopment in Astrocytoma Cells." Journal of Virology 76, no. 10 (May 15, 2002): 5147–55. http://dx.doi.org/10.1128/jvi.76.10.5147-5155.2002.

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ABSTRACT Human cytomegalovirus (HCMV) is a prototypic member of the betaherpesvirus family. The HCMV virion is composed of a large DNA genome encapsidated within a nucleocapsid, which is wrapped within an inner proteinaceous tegument and an outer lipid envelope containing viral glycoproteins. Although genome encapsidation clearly occurs in the nucleus, the subsequent steps in the virion assembly process are unclear. HCMV glycoprotein B (gB) is a major component of the virion envelope that plays a critical role in virus entry and is essential for the production of infectious virus progeny. The aim of our present study was to identify the secretory compartment to which HCMV gB was localized and to investigate the role of endocytosis in mediating gB localization and HCMV biogenesis. We show that HCMV gB is localized to the trans-Golgi network (TGN) in HCMV-infected cells and that gB contains all of the trafficking information necessary for TGN localization. Endocytosis of gB was shown to play a role in mediating TGN localization of gB and in targeting of the protein to the site of virus envelopment. However, inhibition of endocytosis with a dominant-negative dynamin I molecule did not affect the production of infectious virus. These observations indicate that, although endocytosis is involved in the trafficking of gB to the site of glycoprotein accumulation in the TGN, endocytosis of gB is not required for the production of infectious HCMV.

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Kittur, Nupur, Gregory Zapantis, Mira Aubuchon, Nanette Santoro, David P. Bazett-Jones, and U. Thomas Meier. "The Nucleolar Channel System of Human Endometrium Is Related to Endoplasmic Reticulum and R-Rings." Molecular Biology of the Cell 18, no. 6 (June 2007): 2296–304. http://dx.doi.org/10.1091/mbc.e07-02-0154.

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The nucleolar channel system (NCS) is a well-established ultrastructural hallmark of the postovulation endometrium. Its transient presence has been associated with human fertility. Nevertheless, the biogenesis, composition, and function of these intranuclear membrane cisternae are unknown. Membrane systems with a striking ultrastructural resemblance to the NCS, termed R-rings, are induced in nuclei of tissue culture cells by overexpression of the central repeat domain of the nucleolar protein Nopp140. Here we provide a first molecular characterization of the NCS and compare the biogenesis of these two enigmatic organelles. Like the R-rings, the NCS consists of endoplasmic reticulum harboring the marker glucose-6-phosphatase. R-ring formation initiates at the nuclear envelope, apparently by a calcium-mediated Nopp140-membrane interaction, as supported by the calcium-binding ability of Nopp140, the inhibition of R-ring formation by calcium chelators, and the concentration of Nopp140 and complexed calcium in R-rings. Although biogenesis of the NCS may initiate similarly, the reduced presence of complexed calcium and Nopp140 suggests the involvement of additional factors.

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Gobeil, Jr., Fernand, Alejandro Vazquez-Tello, Anne Marilise Marrache, Mosumi Bhattacharya, Daniella Checchin, Ghassan Bkaily, Pierre Lachapelle, Alfredo Ribeiro-Da-Silva, and Sylvain Chemtob. "Nuclear prostaglandin signaling system: biogenesis and actions via heptahelical receptors." Canadian Journal of Physiology and Pharmacology 81, no. 2 (February 1, 2003): 196–204. http://dx.doi.org/10.1139/y02-163.

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Prostaglandins are ubiquitous lipid mediators that play pivotal roles in cardiovascular homeostasis, reproduction, and inflammation, as well as in many important cellular processes including gene expression and cell proliferation. The mechanism of action of these lipid messengers is thought to be primarily dependent on their interaction with specific cell surface receptors that belong to the heptahelical transmembrane spanning G protein-coupled receptor superfamily. Accumulating evidence suggests that these receptors may co-localize at the cell nucleus where they can modulate gene expression through a series of biochemical events. In this context, we have recently demonstrated that prostaglandin E2-EP3 receptors display an atypical nuclear compartmentalization in cerebral microvascular endothelial cells. Stimulation of these nuclear EP3 receptors leads to an increase of eNOS RNA in a cell-free isolated nuclear system. This review will emphasize these findings and describe how nuclear prostaglandin receptors, notably EP3 receptors, may affect gene expression, specifically of eNOS, by identifying putative transducing elements located within this organelle. The potential sources of lipid ligand activators for these intracellular sites will also be addressed. The expressional control of G-protein-coupled receptors located at the perinuclear envelope constitutes a novel and distinctive mode of gene regulation.Key words: PGE2, EP receptors, cell nucleus, signal transduction, gene transcription.

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Bolla, Jani R. "Targeting MmpL3 for anti-tuberculosis drug development." Biochemical Society Transactions 48, no. 4 (July 14, 2020): 1463–72. http://dx.doi.org/10.1042/bst20190950.

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The unique architecture of the mycobacterial cell envelope plays an important role in Mycobacterium tuberculosis (Mtb) pathogenesis. A critical protein in cell envelope biogenesis in mycobacteria, required for transport of precursors, trehalose monomycolates (TMMs), is the Mycobacterial membrane protein large 3 (MmpL3). Due to its central role in TMM transport, MmpL3 has been an attractive therapeutic target and a key target for several preclinical agents. In 2019, the first crystal structures of the MmpL3 transporter and its complexes with lipids and inhibitors were reported. These structures revealed several unique structural features of MmpL3 and provided invaluable information on the mechanism of TMM transport. This review aims to highlight the recent advances made in the function of MmpL3 and summarises structural findings. The overall goal is to provide a mechanistic perspective of MmpL3-mediated lipid transport and inhibition, and to highlight the prospects for potential antituberculosis therapies.

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Dittmann, Karen K., Cisse H. Porsby, Priscila Goncalves, Ramona Valentina Mateiu, Eva C. Sonnenschein, Mikkel Bentzon‐Tilia, Suhelen Egan, and Lone Gram. "Tropodithietic acid induces oxidative stress response, cell envelope biogenesis and iron uptake in Vibrio vulnificus." Environmental Microbiology Reports 11, no. 4 (June 17, 2019): 581–88. http://dx.doi.org/10.1111/1758-2229.12771.

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Journal articles on the topic 'Cell envelope biogenesi'

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