Artículos de revistas: "PEX1"

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Knoops, Kèvin, Rinse de Boer, Anita Kram y Ida J. van der Klei. "Yeast pex1 cells contain peroxisomal ghosts that import matrix proteins upon reintroduction of Pex1". Journal of Cell Biology 211, n.º 5 (7 de diciembre de 2015): 955–62. http://dx.doi.org/10.1083/jcb.201506059.

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Pex1 and Pex6 are two AAA-ATPases that play a crucial role in peroxisome biogenesis. We have characterized the ultrastructure of the Saccharomyces cerevisiae peroxisome-deficient mutants pex1 and pex6 by various high-resolution electron microscopy techniques. We observed that the cells contained peroxisomal membrane remnants, which in ultrathin cross sections generally appeared as double membrane rings. Electron tomography revealed that these structures consisted of one continuous membrane, representing an empty, flattened vesicle, which folds into a cup shape. Immunocytochemistry revealed that these structures lack peroxisomal matrix proteins but are the sole sites of the major peroxisomal membrane proteins Pex2, Pex10, Pex11, Pex13, and Pex14. Upon reintroduction of Pex1 in Pex1-deficient cells, these peroxisomal membrane remnants (ghosts) rapidly incorporated peroxisomal matrix proteins and developed into peroxisomes. Our data support earlier views that Pex1 and Pex6 play a role in peroxisomal matrix protein import.

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Verner, Zdeněk, Vojtěch Žárský, Tien Le, Ravi Kumar Narayanasamy, Petr Rada, Daniel Rozbeský, Abhijith Makki et al. "Anaerobic peroxisomes in Entamoeba histolytica metabolize myo-inositol". PLOS Pathogens 17, n.º 11 (15 de noviembre de 2021): e1010041. http://dx.doi.org/10.1371/journal.ppat.1010041.

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Entamoeba histolytica is believed to be devoid of peroxisomes, like most anaerobic protists. In this work, we provided the first evidence that peroxisomes are present in E. histolytica, although only seven proteins responsible for peroxisome biogenesis (peroxins) were identified (Pex1, Pex6, Pex5, Pex11, Pex14, Pex16, and Pex19). Targeting matrix proteins to peroxisomes is reduced to the PTS1-dependent pathway mediated via the soluble Pex5 receptor, while the PTS2 receptor Pex7 is absent. Immunofluorescence microscopy showed that peroxisomal markers (Pex5, Pex14, Pex16, Pex19) are present in vesicles distinct from mitosomes, the endoplasmic reticulum, and the endosome/phagosome system, except Pex11, which has dual localization in peroxisomes and mitosomes. Immunoelectron microscopy revealed that Pex14 localized to vesicles of approximately 90–100 nm in diameter. Proteomic analyses of affinity-purified peroxisomes and in silico PTS1 predictions provided datasets of 655 and 56 peroxisomal candidates, respectively; however, only six proteins were shared by both datasets, including myo-inositol dehydrogenase (myo-IDH). Peroxisomal NAD-dependent myo-IDH appeared to be a dimeric enzyme with high affinity to myo-inositol (Km 0.044 mM) and can utilize also scyllo-inositol, D-glucose and D-xylose as substrates. Phylogenetic analyses revealed that orthologs of myo-IDH with PTS1 are present in E. dispar, E. nutalli and E. moshkovskii but not in E. invadens, and form a monophyletic clade of mostly peroxisomal orthologs with free-living Mastigamoeba balamuthi and Pelomyxa schiedti. The presence of peroxisomes in E. histolytica and other archamoebae breaks the paradigm of peroxisome absence in anaerobes and provides a new potential target for the development of antiparasitic drugs.

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Agrawal, Gaurav, Scott N. Fassas, Zhi-Jie Xia y Suresh Subramani. "Distinct requirements for intra-ER sorting and budding of peroxisomal membrane proteins from the ER". Journal of Cell Biology 212, n.º 3 (1 de febrero de 2016): 335–48. http://dx.doi.org/10.1083/jcb.201506141.

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During de novo peroxisome biogenesis, importomer complex proteins sort via two preperoxisomal vesicles (ppVs). However, the sorting mechanisms segregating peroxisomal membrane proteins to the preperoxisomal endoplasmic reticulum (pER) and into ppVs are unknown. We report novel roles for Pex3 and Pex19 in intra–endoplasmic reticulum (ER) sorting and budding of the RING-domain peroxins (Pex2, Pex10, and Pex12). Pex19 bridged the interaction at the ER between Pex3 and RING-domain proteins, resulting in a ternary complex that was critical for the intra-ER sorting and subsequent budding of the RING-domain peroxins. Although the docking subcomplex proteins (Pex13, Pex14, and Pex17) also required Pex19 for budding from the ER, they sorted to the pER independently of Pex3 and Pex19 and were spatially segregated from the RING-domain proteins. We also discovered a unique role for Pex3 in sorting Pex10 and Pex12, but with the docking subcomplex. Our study describes an intra-ER sorting process that regulates segregation, packaging, and budding of peroxisomal importomer subcomplexes, thereby preventing their premature assembly at the ER.

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Miyata, Non y Yukio Fujiki. "Shuttling Mechanism of Peroxisome Targeting Signal Type 1 Receptor Pex5: ATP-Independent Import and ATP-Dependent Export". Molecular and Cellular Biology 25, n.º 24 (15 de diciembre de 2005): 10822–32. http://dx.doi.org/10.1128/mcb.25.24.10822-10832.2005.

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ABSTRACT Peroxisomal matrix proteins are posttranslationally imported into peroxisomes with the peroxisome-targeting signal 1 receptor, Pex5. The longer isoform of Pex5, Pex5L, also transports Pex7-PTS2 protein complexes. After unloading the cargoes, Pex5 returns to the cytosol. To address molecular mechanisms underlying Pex5 functions, we constructed a cell-free Pex5 translocation system with a postnuclear supernatant fraction from CHO cell lines. In assays using the wild-type CHO-K1 cell fraction, 35S-labeled Pex5 was specifically imported into and exported from peroxisomes with multiple rounds. 35S-Pex5 import was also evident using peroxisomes isolated from rat liver. ATP was not required for 35S-Pex5 import but was indispensable for export. 35S-Pex5 was imported neither to peroxisome remnants from RING peroxin-deficient cell mutants nor to those from pex14 cells lacking a Pex5-docking site. In contrast, 35S-Pex5 was imported into the peroxisome remnants of PEX1-, PEX6-, and PEX26-defective cell mutants, including those from patients with peroxisome biogenesis disorders, from which, however, 35S-Pex5 was not exported, thereby indicating that Pex1 and Pex6 of the AAA ATPase family and their recruiter, Pex26, were essential for Pex5 export. Moreover, we analyzed the 35S-Pex5-associated complexes on peroxisomal membranes by blue-native polyacrylamide gel electrophoresis. 35S-Pex5 was in two distinct, 500- and 800-kDa complexes comprising different sets of peroxins, such as Pex14 and Pex2, implying that Pex5 transited between the subcomplexes. Together, results indicated that Pex5 most likely enters peroxisomes, changes its interacting partners, and then exits using ATP energy.

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5

Gonzalez, Kim L., Sarah E. Ratzel, Kendall H. Burks, Charles H. Danan, Jeanne M. Wages, Bethany K. Zolman y Bonnie Bartel. "A pex1 missense mutation improves peroxisome function in a subset of Arabidopsis pex6 mutants without restoring PEX5 recycling". Proceedings of the National Academy of Sciences 115, n.º 14 (19 de marzo de 2018): E3163—E3172. http://dx.doi.org/10.1073/pnas.1721279115.

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Peroxisomes are eukaryotic organelles critical for plant and human development because they house essential metabolic functions, such as fatty acid β-oxidation. The interacting ATPases PEX1 and PEX6 contribute to peroxisome function by recycling PEX5, a cytosolic receptor needed to import proteins targeted to the peroxisomal matrix. Arabidopsis pex6 mutants exhibit low PEX5 levels and defects in peroxisomal matrix protein import, oil body utilization, peroxisomal metabolism, and seedling growth. These defects are hypothesized to stem from impaired PEX5 retrotranslocation leading to PEX5 polyubiquitination and consequent degradation of PEX5 via the proteasome or of the entire organelle via autophagy. We recovered a pex1 missense mutation in a screen for second-site suppressors that restore growth to the pex6-1 mutant. Surprisingly, this pex1-1 mutation ameliorated the metabolic and physiological defects of pex6-1 without restoring PEX5 levels. Similarly, preventing autophagy by introducing an atg7-null allele partially rescued pex6-1 physiological defects without restoring PEX5 levels. atg7 synergistically improved matrix protein import in pex1-1 pex6-1, implying that pex1-1 improves peroxisome function in pex6-1 without impeding autophagy of peroxisomes (i.e., pexophagy). pex1-1 differentially improved peroxisome function in various pex6 alleles but worsened the physiological and molecular defects of a pex26 mutant, which is defective in the tether anchoring the PEX1–PEX6 hexamer to the peroxisome. Our results support the hypothesis that, beyond PEX5 recycling, PEX1 and PEX6 have additional functions in peroxisome homeostasis and perhaps in oil body utilization.

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Titorenko, V. I., D. M. Ogrydziak y R. A. Rachubinski. "Four distinct secretory pathways serve protein secretion, cell surface growth, and peroxisome biogenesis in the yeast Yarrowia lipolytica." Molecular and Cellular Biology 17, n.º 9 (septiembre de 1997): 5210–26. http://dx.doi.org/10.1128/mcb.17.9.5210.

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We have identified and characterized mutants of the yeast Yarrowia lipolytica that are deficient in protein secretion, in the ability to undergo dimorphic transition from the yeast to the mycelial form, and in peroxisome biogenesis. Mutations in the SEC238, SRP54, PEX1, PEX2, PEX6, and PEX9 genes affect protein secretion, prevent the exit of the precursor form of alkaline extracellular protease from the endoplasmic reticulum, and compromise peroxisome biogenesis. The mutants sec238A, srp54KO, pex2KO, pex6KO, and pex9KO are also deficient in the dimorphic transition from the yeast to the mycelial form and are affected in the export of only plasma membrane and cell wall-associated proteins specific for the mycelial form. Mutations in the SEC238, SRP54, PEX1, and PEX6 genes prevent or significantly delay the exit of two peroxisomal membrane proteins, Pex2p and Pex16p, from the endoplasmic reticulum en route to the peroxisomal membrane. Mutations in the PEX5, PEX16, and PEX17 genes, which have previously been shown to be essential for peroxisome biogenesis, affect the export of plasma membrane and cell wall-associated proteins specific for the mycelial form but do not impair exit from the endoplasmic reticulum of either Pex2p and Pex16p or of proteins destined for secretion. Biochemical analyses of these mutants provide evidence for the existence of four distinct secretory pathways that serve to deliver proteins for secretion, plasma membrane and cell wall synthesis during yeast and mycelial modes of growth, and peroxisome biogenesis. At least two of these secretory pathways, which are involved in the export of proteins to the external medium and in the delivery of proteins for assembly of the peroxisomal membrane, diverge at the level of the endoplasmic reticulum.

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Chang, C. C., S. South, D. Warren, J. Jones, A. B. Moser, H. W. Moser y S. J. Gould. "Metabolic control of peroxisome abundance". Journal of Cell Science 112, n.º 10 (15 de mayo de 1999): 1579–90. http://dx.doi.org/10.1242/jcs.112.10.1579.

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Zellweger syndrome and related disorders represent a group of lethal, genetically heterogeneous diseases. These peroxisome biogenesis disorders (PBDs) are characterized by defective peroxisomal matrix protein import and comprise at least 10 complementation groups. The genes defective in seven of these groups and more than 90% of PBD patients are now known. Here we examine the distribution of peroxisomal membrane proteins in fibroblasts from PBD patients representing the seven complementation groups for which the mutant gene is known. Peroxisomes were detected in all PBD cells, indicating that the ability to form a minimal peroxisomal structure is not blocked in these mutants. We also observed that peroxisome abundance was reduced fivefold in PBD cells that are defective in the PEX1, PEX5, PEX12, PEX6, PEX10, and PEX2 genes. These cell lines all display a defect in the import of proteins with the type-1 peroxisomal targeting signal (PTS1). In contrast, peroxisome abundance was unaffected in cells that are mutated in PEX7 and are defective only in the import of proteins with the type-2 peroxisomal targeting signal. Interestingly, a fivefold reduction in peroxisome abundance was also observed for cells lacking either of two PTS1-targeted peroxisomal beta-oxidation enzymes, acyl-CoA oxidase and 2-enoyl-CoA hydratase/D-3-hydroxyacyl-CoA dehydrogenase. These results indicate that reduced peroxisome abundance in PBD cells may be caused by their inability to import these PTS1-containing enzymes. Furthermore, the fact that peroxisome abundance is influenced by peroxisomal 105-oxidation activities suggests that there may be metabolic control of peroxisome abundance.

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Knoops, Kèvin, Selvambigai Manivannan, Małgorzata N. Cepińska, Arjen M. Krikken, Anita M. Kram, Marten Veenhuis y Ida J. van der Klei. "Preperoxisomal vesicles can form in the absence of Pex3". Journal of Cell Biology 204, n.º 5 (3 de marzo de 2014): 659–68. http://dx.doi.org/10.1083/jcb.201310148.

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We demonstrate that the peroxin Pex3 is not required for the formation of peroxisomal membrane structures in yeast pex3 mutant cells. Notably, pex3 mutant cells already contain reticular and vesicular structures that harbor key proteins of the peroxisomal receptor docking complex—Pex13 and Pex14—as well as the matrix proteins Pex8 and alcohol oxidase. Other peroxisomal membrane proteins in these cells are unstable and transiently localized to the cytosol (Pex10, Pmp47) or endoplasmic reticulum (Pex11). These reticular and vesicular structures are more abundant in cells of a pex3 atg1 double deletion strain, as the absence of Pex3 may render them susceptible to autophagic degradation, which is blocked in this double mutant. Contrary to earlier suggestions, peroxisomes are not formed de novo from the endoplasmic reticulum when the PEX3 gene is reintroduced in pex3 cells. Instead, we find that reintroduced Pex3 sorts to the preperoxisomal structures in pex3 cells, after which these structures mature into normal peroxisomes.

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Platta, Harald W., Fouzi El Magraoui, Bastian E. Bäumer, Daniel Schlee, Wolfgang Girzalsky y Ralf Erdmann. "Pex2 and Pex12 Function as Protein-Ubiquitin Ligases in Peroxisomal Protein Import". Molecular and Cellular Biology 29, n.º 20 (17 de agosto de 2009): 5505–16. http://dx.doi.org/10.1128/mcb.00388-09.

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ABSTRACT The PTS1-dependent peroxisomal matrix protein import is facilitated by the receptor protein Pex5 and can be divided into cargo recognition in the cytosol, membrane docking of the cargo-receptor complex, cargo release, and recycling of the receptor. The final step is controlled by the ubiquitination status of Pex5. While polyubiquitinated Pex5 is degraded by the proteasome, monoubiquitinated Pex5 is destined for a new round of the receptor cycle. Recently, the ubiquitin-conjugating enzymes involved in Pex5 ubiquitination were identified as Ubc4 and Pex4 (Ubc10), whereas the identity of the corresponding protein-ubiquitin ligases remained unknown. Here we report on the identification of the protein-ubiquitin ligases that are responsible for the ubiquitination of the peroxisomal protein import receptor Pex5. It is demonstrated that each of the three RING peroxins Pex2, Pex10, and Pex12 exhibits ubiquitin-protein isopeptide ligase activity. Our results show that Pex2 mediates the Ubc4-dependent polyubiquitination whereas Pex12 facilitates the Pex4-dependent monoubiquitination of Pex5.

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Judy, Ryan M., Connor J. Sheedy y Brooke M. Gardner. "Insights into the Structure and Function of the Pex1/Pex6 AAA-ATPase in Peroxisome Homeostasis". Cells 11, n.º 13 (29 de junio de 2022): 2067. http://dx.doi.org/10.3390/cells11132067.

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The AAA-ATPases Pex1 and Pex6 are required for the formation and maintenance of peroxisomes, membrane-bound organelles that harbor enzymes for specialized metabolism. Together, Pex1 and Pex6 form a heterohexameric AAA-ATPase capable of unfolding substrate proteins via processive threading through a central pore. Here, we review the proposed roles for Pex1/Pex6 in peroxisome biogenesis and degradation, discussing how the unfolding of potential substrates contributes to peroxisome homeostasis. We also consider how advances in cryo-EM, computational structure prediction, and mechanisms of related ATPases are improving our understanding of how Pex1/Pex6 converts ATP hydrolysis into mechanical force. Since mutations in PEX1 and PEX6 cause the majority of known cases of peroxisome biogenesis disorders such as Zellweger syndrome, insights into Pex1/Pex6 structure and function are important for understanding peroxisomes in human health and disease.

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Motley, Alison M., Paul C. Galvin, Lakhan Ekal, James M. Nuttall y Ewald H. Hettema. "Reevaluation of the role of Pex1 and dynamin-related proteins in peroxisome membrane biogenesis". Journal of Cell Biology 211, n.º 5 (7 de diciembre de 2015): 1041–56. http://dx.doi.org/10.1083/jcb.201412066.

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A recent model for peroxisome biogenesis postulates that peroxisomes form de novo continuously in wild-type cells by heterotypic fusion of endoplasmic reticulum–derived vesicles containing distinct sets of peroxisomal membrane proteins. This model proposes a role in vesicle fusion for the Pex1/Pex6 complex, which has an established role in matrix protein import. The growth and division model proposes that peroxisomes derive from existing peroxisomes. We tested these models by reexamining the role of Pex1/Pex6 and dynamin-related proteins in peroxisome biogenesis. We found that induced depletion of Pex1 blocks the import of matrix proteins but does not affect membrane protein delivery to peroxisomes; markers for the previously reported distinct vesicles colocalize in pex1 and pex6 cells; peroxisomes undergo continued growth if fission is blocked. Our data are compatible with the established primary role of the Pex1/Pex6 complex in matrix protein import and show that peroxisomes in Saccharomyces cerevisiae multiply mainly by growth and division.

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Blok, Neil B., Dongyan Tan, Ray Yu-Ruei Wang, Pawel A. Penczek, David Baker, Frank DiMaio, Tom A. Rapoport y Thomas Walz. "Unique double-ring structure of the peroxisomal Pex1/Pex6 ATPase complex revealed by cryo-electron microscopy". Proceedings of the National Academy of Sciences 112, n.º 30 (13 de julio de 2015): E4017—E4025. http://dx.doi.org/10.1073/pnas.1500257112.

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Members of the AAA family of ATPases assemble into hexameric double rings and perform vital functions, yet their molecular mechanisms remain poorly understood. Here, we report structures of the Pex1/Pex6 complex; mutations in these proteins frequently cause peroxisomal diseases. The structures were determined in the presence of different nucleotides by cryo-electron microscopy. Models were generated using a computational approach that combines Monte Carlo placement of structurally homologous domains into density maps with energy minimization and refinement protocols. Pex1 and Pex6 alternate in an unprecedented hexameric double ring. Each protein has two N-terminal domains, N1 and N2, structurally related to the single N domains in p97 and N-ethylmaleimide sensitive factor (NSF); N1 of Pex1 is mobile, but the others are packed against the double ring. The N-terminal ATPase domains are inactive, forming a symmetric D1 ring, whereas the C-terminal domains are active, likely in different nucleotide states, and form an asymmetric D2 ring. These results suggest how subunit activity is coordinated and indicate striking similarities between Pex1/Pex6 and p97, supporting the hypothesis that the Pex1/Pex6 complex has a role in peroxisomal protein import analogous to p97 in ER-associated protein degradation.

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Idnurm, Alexander, Steven S. Giles, John R. Perfect y Joseph Heitman. "Peroxisome Function Regulates Growth on Glucose in the Basidiomycete Fungus Cryptococcus neoformans". Eukaryotic Cell 6, n.º 1 (13 de octubre de 2006): 60–72. http://dx.doi.org/10.1128/ec.00214-06.

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ABSTRACT The function of the peroxisomes was examined in the pathogenic basidiomycete Cryptococcus neoformans. Recent studies reveal the glyoxylate pathway is required for virulence of diverse microbial pathogens of plants and animals. One exception is C. neoformans, in which isocitrate lyase (encoded by ICL1) was previously shown not to be required for virulence, and here this was extended to exclude also a role for malate synthase (encoded by MLS1). The role of peroxisomes, in which the glyoxylate pathway enzymes are localized in many organisms, was examined by mutation of two genes (PEX1 and PEX6) encoding AAA (ATPases associated with various cellular activities)-type proteins required for peroxisome formation. The pex1 and pex6 deletion mutants were unable to localize the fluorescent DsRED-SKL protein to peroxisomal punctate structures, in contrast to wild-type cells. pex1 and pex6 single mutants and a pex1 pex6 double mutant exhibit identical phenotypes, including abolished growth on fatty acids but no growth difference on acetate. Because both icl1 and mls1 mutants are unable to grow on acetate as the sole carbon source, these findings demonstrate that the glyoxylate pathway can function efficiently outside the peroxisome in C. neoformans. The pex1 mutant exhibits wild-type virulence in a murine inhalation model and in an insect host, demonstrating that peroxisomes are not required for virulence under these conditions. An unusual phenotype of the pex1 and pex6 mutants was that they grew poorly with glucose as the carbon source, but nearly wild type with galactose, which suggested impaired hexokinase function and that C. neoformans peroxisomes might function analogously to the glycosomes of the trypanosomid parasites. Deletion of the hexokinase HXK2 gene reduced growth in the presence of glucose and suppressed the growth defect of the pex1 mutant on glucose. The hexokinase 2 protein of C. neoformans contains a predicted peroxisome targeting signal (type 2) motif; however, Hxk2 fused to fluorescent proteins was not localized to peroxisomes. Thus, we hypothesize that glucose or glycolytic metabolites are utilized in the peroxisome by an as yet unidentified enzyme or regulate a pathway required by the fungus in the absence of peroxisomes.

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Schell-Steven, Annette, Katharina Stein, Mara Amoros, Christiane Landgraf, Rudolf Volkmer-Engert, Hanspeter Rottensteiner y Ralf Erdmann. "Identification of a Novel, Intraperoxisomal Pex14-Binding Site in Pex13: Association of Pex13 with the Docking Complex Is Essential for Peroxisomal Matrix Protein Import". Molecular and Cellular Biology 25, n.º 8 (15 de abril de 2005): 3007–18. http://dx.doi.org/10.1128/mcb.25.8.3007-3018.2005.

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ABSTRACT The peroxisomal docking complex is a key component of the import machinery for matrix proteins. The core protein of this complex, Pex14, is thought to represent the initial docking site for the import receptors Pex5 and Pex7. Associated with this complex is a fraction of Pex13, another essential component of the import machinery. Here we demonstrate that Pex13 directly binds Pex14 not only via its SH3 domain but also via a novel intraperoxisomal site. Furthermore, we demonstrate that Pex5 also contributes to the association of Pex13 with Pex14. Peroxisome function was affected only mildly by mutations within the novel Pex14 interaction site of Pex13 or by the non-Pex13-interacting mutant Pex5W204A. However, when these constructs were tested in combination, PTS1-dependent import and growth on oleic acid were severely compromised. When the SH3 domain-mediated interaction of Pex13 with Pex14 was blocked on top of that, PTS2-dependent matrix protein import was completely compromised and Pex13 was no longer copurified with the docking complex. We conclude that the association of Pex13 with Pex14 is an essential step in peroxisomal protein import that is enabled by two direct interactions and by one that is mediated by Pex5, a result which indicates a novel, receptor-independent function of Pex5.

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Havali, Cengiz, Sevil Dorum, Yılmaz Akbaş, Orhan Görükmez y Tugba Hirfanoglu. "Two different missense mutations of PEX genes in two similar patients with severe Zellweger syndrome: an argument on the genotype-phenotype correlation". Journal of Pediatric Endocrinology and Metabolism 33, n.º 3 (26 de marzo de 2020): 437–41. http://dx.doi.org/10.1515/jpem-2019-0194.

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AbstractBackgroundPeroxisomal biogenesis disorders (PBDs) include a miscellaneous group of diseases which cause serious multisystem disease. Mutations of 13 different PEX genes lead to PBDs including Zellweger syndrome (ZS). Different types of mutations of PEX1 and PEX10 genes are correlated with broad-range phenotypes of PBDs.Case presentationPatient 1 is a 4-month-old boy who was affected by myoclonic seizures, poor oral feeding since birth. The patient was hypotonic and had hepatosplenomegaly. Patient 2 is a 2-month-old boy who presented with decreased movement, severe hypotonia and failure to thrive. The laboratory studies of the patients revealed increased plasma very-long-chain fatty acids (VLCFAs). The genetic analyses of patient 1 demonstrated the first homozygous missense mutation in the PEX10 gene. A novel homozygous missense mutation was found in the PEX1 gene in patient 2.ConclusionsThis report highlights that the detected homozygous missense mutations of PEX10 and PEX1 genes and the substitutions of specific amino acids lead to the severe form of PBDs.

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Schieferdecker, Anne y Petra Wendler. "Structural Mapping of Missense Mutations in the Pex1/Pex6 Complex". International Journal of Molecular Sciences 20, n.º 15 (1 de agosto de 2019): 3756. http://dx.doi.org/10.3390/ijms20153756.

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Peroxisome biogenesis disorders (PBDs) are nontreatable hereditary diseases with a broad range of severity. Approximately 65% of patients are affected by mutations in the peroxins Pex1 and Pex6. The proteins form the heteromeric Pex1/Pex6 complex, which is important for protein import into peroxisomes. To date, no structural data are available for this AAA+ ATPase complex. However, a wealth of information can be transferred from low-resolution structures of the yeast scPex1/scPex6 complex and homologous, well-characterized AAA+ ATPases. We review the abundant records of missense mutations described in PBD patients with the aim to classify and rationalize them by mapping them onto a homology model of the human Pex1/Pex6 complex. Several mutations concern functionally conserved residues that are implied in ATP hydrolysis and substrate processing. Contrary to fold destabilizing mutations, patients suffering from function-impairing mutations may not benefit from stabilizing agents, which have been reported as potential therapeutics for PBD patients.

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Collins, Cynthia S., Jennifer E. Kalish, James C. Morrell, J. Michael McCaffery y Stephen J. Gould. "The Peroxisome Biogenesis Factors Pex4p, Pex22p, Pex1p, and Pex6p Act in the Terminal Steps of Peroxisomal Matrix Protein Import". Molecular and Cellular Biology 20, n.º 20 (15 de octubre de 2000): 7516–26. http://dx.doi.org/10.1128/mcb.20.20.7516-7526.2000.

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ABSTRACT Peroxisomes are independent organelles found in virtually all eukaryotic cells. Genetic studies have identified more than 20PEX genes that are required for peroxisome biogenesis. The role of most PEX gene products, peroxins, remains to be determined, but a variety of studies have established that Pex5p binds the type 1 peroxisomal targeting signal and is the import receptor for most newly synthesized peroxisomal matrix proteins. The steady-state abundance of Pex5p is unaffected in mostpex mutants of the yeast Pichia pastorisbut is severely reduced in pex4 andpex22 mutants and moderately reduced in pex1and pex6 mutants. We used these subphenotypes to determine the epistatic relationships among several groups ofpex mutants. Our results demonstrate that Pex4p acts after the peroxisome membrane synthesis factor Pex3p, the Pex5p docking factors Pex13p and Pex14p, the matrix protein import factors Pex8p, Pex10p, and Pex12p, and two other peroxins, Pex2p and Pex17p. Pex22p and the interacting AAA ATPases Pex1p and Pex6p were also found to act after Pex10p. Furthermore, Pex1p and Pex6p were found to act upstream of Pex4p and Pex22p. These results suggest that Pex1p, Pex4p, Pex6p, and Pex22p act late in peroxisomal matrix protein import, after matrix protein translocation. This hypothesis is supported by the phenotypes of the corresponding mutant strains. As has been shown previously for P. pastoris pex1,pex6, and pex22 mutant cells, we show here thatpex4Δ mutant cells contain peroxisomal membrane protein-containing peroxisomes that import residual amounts of peroxisomal matrix proteins.

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Nuttall, James M., Alison M. Motley y Ewald H. Hettema. "Deficiency of the exportomer components Pex1, Pex6, and Pex15 causes enhanced pexophagy inSaccharomyces cerevisiae". Autophagy 10, n.º 5 (18 de marzo de 2014): 835–45. http://dx.doi.org/10.4161/auto.28259.

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Fujiki, Yukio, Non Miyata, Naomi Matsumoto y Shigehiko Tamura. "Dynamic and functional assembly of the AAA peroxins, Pex1p and Pex6p, and their membrane receptor Pex26p involved in shuttling of the PTS1 receptor Pex5p in peroxisome biogenesis". Biochemical Society Transactions 36, n.º 1 (22 de enero de 2008): 109–13. http://dx.doi.org/10.1042/bst0360109.

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The peroxisome is a single-membrane-bound organelle found in eukaryotes. The functional importance of peroxisomes in humans is highlighted by peroxisome-deficient PBDs (peroxisome biogenesis disorders), such as Zellweger syndrome. Two AAA (ATPase associated with various cellular activities) peroxins, Pex1p and Pex6p, are encoded by PEX1 and PEX6, the causal genes for CG (complementation group) 1 and CG4 PBDs respectively. PEX26, which is responsible for CG8 PBDs, codes for Pex26p, the recruiter of Pex1p–Pex6p complexes to peroxisomes. We recently assigned the binding regions between human Pex1p and Pex6p and elucidated the pivotal roles that the AAA cassettes, D1 and D2 domains, play in Pex1p–Pex6p interaction and in peroxisome biogenesis. ATP binding to both AAA cassettes of Pex1p and Pex6p was a prerequisite for the Pex1p–Pex6p interaction and peroxisomal localization, but ATP hydrolysis by the D2 domains was not required. Pex1p exists in two distinct oligomeric forms, a homo-oligomer in the cytosol and a hetero-oligomer on peroxisome membranes, with these possibly having distinct functions in peroxisome biogenesis. AAA peroxins are involved in the export from peroxisomes of Pex5p, the PTS1 (peroxisome-targeting signal type 1) receptor.

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Smith, Claire E. L., James A. Poulter, Alex V. Levin, Jenina E. Capasso, Susan Price, Tamar Ben-Yosef, Reuven Sharony et al. "Spectrum of PEX1 and PEX6 variants in Heimler syndrome". European Journal of Human Genetics 24, n.º 11 (15 de junio de 2016): 1565–71. http://dx.doi.org/10.1038/ejhg.2016.62.

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Chang, Chia-Che, Daniel S. Warren, Katherine A. Sacksteder y Stephen J. Gould. "Pex12 Interacts with Pex5 and Pex10 and Acts Downstream of Receptor Docking in Peroxisomal Matrix Protein Import". Journal of Cell Biology 147, n.º 4 (15 de noviembre de 1999): 761–74. http://dx.doi.org/10.1083/jcb.147.4.761.

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Peroxisomal matrix protein import requires PEX12, an integral peroxisomal membrane protein with a zinc ring domain at its carboxy terminus. Mutations in human PEX12 result in Zellweger syndrome, a lethal neurological disorder, and implicate the zinc ring domain in PEX12 function. Using two-hybrid studies, blot overlay assays, and coimmunoprecipitation experiments, we observed that the zinc-binding domain of PEX12 binds both PEX5, the PTS1 receptor, and PEX10, another integral peroxisomal membrane protein required for peroxisomal matrix protein import. Furthermore, we identified a patient with a missense mutation in the PEX12 zinc-binding domain, S320F, and observed that this mutation reduces the binding of PEX12 to PEX5 and PEX10. Overexpression of either PEX5 or PEX10 can suppress this PEX12 mutation, providing genetic evidence that these interactions are biologically relevant. PEX5 is a predominantly cytoplasmic protein and previous PEX5-binding proteins have been implicated in docking PEX5 to the peroxisome surface. However, we find that loss of PEX12 or PEX10 does not reduce the association of PEX5 with peroxisomes, demonstrating that these peroxins are not required for receptor docking. These and other results lead us to propose that PEX12 and PEX10 play direct roles in peroxisomal matrix protein import downstream of the receptor docking event.

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TAMURA, Shigehiko, Naomi MATSUMOTO, Atsushi IMAMURA, Nobuyuki SHIMOZAWA, Yasuyuki SUZUKI, Naomi KONDO y Yukio FUJIKI. "Phenotype–genotype relationships in peroxisome biogenesis disorders of PEX1-defective complementation group 1 are defined by Pex1p–Pex6p interaction". Biochemical Journal 357, n.º 2 (9 de julio de 2001): 417–26. http://dx.doi.org/10.1042/bj3570417.

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The peroxisome biogenesis disorders (PBDs), including Zellweger syndrome (ZS), neonatal adrenoleucodystrophy (NALD) and infantile Refsum disease (IRD), are fatal autosomal recessive diseases caused by impaired peroxisome biogenesis, of which 12 genotypes have been reported. ZS patients manifest the severest clinical and biochemical abnormalities, whereas those with NALD and IRD show less severity and the mildest features respectively. We have reported previously that temperature-sensitive peroxisome assembly is responsible for the mildness of the clinical features of IRD. PEX1 is the causative gene for PBDs of complementation group E (CG-E, CG1 in the U.S.A. and Europe), the PBDs of highest incidence, encoding the peroxin Pex1p of the AAA ATPase family. It has been also reported that Pex1p and Pex6p interact with each other. In the present study we investigated phenotype–genotype relationships of CG1 PBDs. Pex1p from IRD such as Pex1p with the most frequently identified mutation at G843D was largely degraded in vivo at 37°C, whereas a normal level of Pex1p was detectable at the permissive temperature. In contrast, PEX1 proteins derived from ZS patients, including proteins with a mutation at L664P or the deletion of residues 634–690, were stably present at both temperatures. Pex1p-G843D interacted with Pex6p at approx. 50% of the level of normal Pex1p, whereas Pex1p from ZS patients mostly showing non-temperature-sensitive peroxisome biogenesis hardly bound to Pex6p. Taking these results together, we consider it most likely that the stability of Pex1p reflects temperature-sensitive peroxisome assembly in IRD fibroblasts. Failure in Pex1p–Pex6p interaction gives rise to more severe abnormalities, such as those manifested by patients with ZS.

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23

Titorenko, Vladimir I. y Richard A. Rachubinski. "Mutants of the Yeast Yarrowia lipolyticaDefective in Protein Exit from the Endoplasmic Reticulum Are Also Defective in Peroxisome Biogenesis". Molecular and Cellular Biology 18, n.º 5 (1 de mayo de 1998): 2789–803. http://dx.doi.org/10.1128/mcb.18.5.2789.

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ABSTRACT Mutations in the SEC238 and SRP54 genes of the yeast Yarrowia lipolytica not only cause temperature-sensitive defects in the exit of the precursor form of alkaline extracellular protease and of other secretory proteins from the endoplasmic reticulum and in protein secretion but also lead to temperature-sensitive growth in oleic acid-containing medium, the metabolism of which requires the assembly of functionally intact peroxisomes. The sec238A andsrp54KO mutations at the restrictive temperature significantly reduce the size and number of peroxisomes, affect the import of peroxisomal matrix and membrane proteins into the organelle, and significantly delay, but do not prevent, the exit of two peroxisomal membrane proteins, Pex2p and Pex16p, from the endoplasmic reticulum en route to the peroxisomal membrane. Mutations in the PEX1 and PEX6 genes, which encode members of the AAA family of N-ethylmaleimide-sensitive fusion protein-like ATPases, not only affect the exit of precursor forms of secretory proteins from the endoplasmic reticulum but also prevent the exit of the peroxisomal membrane proteins Pex2p and Pex16p from the endoplasmic reticulum and cause the accumulation of an extensive network of endoplasmic reticulum membranes. None of the peroxisomal matrix proteins tested associated with the endoplasmic reticulum in sec238A,srp54KO, pex1-1, and pex6KO mutant cells. Our data provide evidence that the endoplasmic reticulum is required for peroxisome biogenesis and suggest that inY. lipolytica, the trafficking of some membrane proteins, but not matrix proteins, to the peroxisome occurs via the endoplasmic reticulum, results in their glycosylation within the lumen of the endoplasmic reticulum, does not involve transport through the Golgi, and requires the products encoded by the SEC238, SRP54,PEX1, and PEX6 genes.

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Mauriac, Stephanie A., Thibault Peineau, Aamir Zuberi, Cathleen Lutz y Gwénaëlle S. G. Géléoc. "Loss of Pex1 in Inner Ear Hair Cells Contributes to Cochlear Synaptopathy and Hearing Loss". Cells 11, n.º 24 (9 de diciembre de 2022): 3982. http://dx.doi.org/10.3390/cells11243982.

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Peroxisome Biogenesis Disorders (PBD) and Zellweger syndrome spectrum disorders (ZSD) are rare genetic multisystem disorders that include hearing impairment and are associated with defects in peroxisome assembly, function, or both. Mutations in 13 peroxin (PEX) genes have been found to cause PBD-ZSD with ~70% of patients harboring mutations in PEX1. Limited research has focused on the impact of peroxisomal disorders on auditory function. As sensory hair cells are particularly vulnerable to metabolic changes, we hypothesize that mutations in PEX1 lead to oxidative stress affecting hair cells of the inner ear, subsequently resulting in hair cell degeneration and hearing loss. Global deletion of the Pex1 gene is neonatal lethal in mice, impairing any postnatal studies. To overcome this limitation, we created conditional knockout mice (cKO) using Gfi1Creor VGlut3Cre expressing mice crossed to floxed Pex1 mice to allow for selective deletion of Pex1 in the hair cells of the inner ear. We find that Pex1 excision in inner hair cells (IHCs) leads to progressive hearing loss associated with significant decrease in auditory brainstem responses (ABR), specifically ABR wave I amplitude, indicative of synaptic defects. Analysis of IHC synapses in cKO mice reveals a decrease in ribbon synapse volume and functional alterations in exocytosis. Concomitantly, we observe a decrease in peroxisomal number, indicative of oxidative stress imbalance. Taken together, these results suggest a critical function of Pex1 in development and maturation of IHC-spiral ganglion synapses and auditory function.

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Saveria, Tracy, André Halbach, Ralf Erdmann, Rudolf Volkmer-Engert, Christiane Landgraf, Hanspeter Rottensteiner y Marilyn Parsons. "Conservation of PEX19-Binding Motifs Required for Protein Targeting to Mammalian Peroxisomal and Trypanosome Glycosomal Membranes". Eukaryotic Cell 6, n.º 8 (22 de junio de 2007): 1439–49. http://dx.doi.org/10.1128/ec.00084-07.

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ABSTRACT Glycosomes are divergent peroxisomes found in trypanosomatid protozoa, including those that cause severe human diseases throughout much of the world. While peroxisomes are dispensable for both yeast (Saccharomyces cerevisiae and others) and mammalian cells in vitro, glycosomes are essential for trypanosomes and hence are viewed as a potential drug target. The import of proteins into the matrix of peroxisomes utilizes multiple peroxisomal membrane proteins which require the peroxin PEX19 for insertion into the peroxisomal membrane. In this report, we show that the specificity of peroxisomal membrane protein binding for Trypanosoma brucei PEX19 is very similar to those previously identified for human and yeast PEX19. Our studies show that trafficking is conserved across these distant phyla and that both a PEX19 binding site and a transmembrane domain are required for the insertion of two test proteins into the glycosomal membrane. However, in contrast to T. brucei PEX10 and PEX12, T. brucei PEX14 does not traffic to human peroxisomes, indicating that it is not recognized by the human PEX14 import mechanism.

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26

Min, Kyunghun, Hokyoung Son, Jungkwan Lee, Gyung Ja Choi, Jin-Cheol Kim y Yin-Won Lee. "Peroxisome Function Is Required for Virulence and Survival of Fusarium graminearum". Molecular Plant-Microbe Interactions® 25, n.º 12 (diciembre de 2012): 1617–27. http://dx.doi.org/10.1094/mpmi-06-12-0149-r.

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Peroxisomes are organelles that are involved in a number of important cellular metabolic processes, including the β-oxidation of fatty acids, biosynthesis of secondary metabolites, and detoxification of reactive oxygen species (ROS). In this study, the role of peroxisomes was examined in Fusarium graminearum by targeted deletion of three genes (PEX5, PEX6, and PEX7) encoding peroxin (PEX) proteins required for peroxisomal protein import. PEX5 and PEX7 deletion mutants were unable to localize the fluorescently tagged peroxisomal targeting signal type 1 (PTS1)- and PTS2-containing proteins to peroxisomes, respectively, whereas the PEX6 mutant failed to localize both fluorescent proteins. Deletion of PEX5 and PEX6 resulted in retarded growth on long-chain fatty acids and butyrate, while the PEX7 deletion mutants utilized fatty acids other than butyrate. Virulence on wheat heads was greatly reduced in the PEX5 and PEX6 deletion mutants, and they were defective in spreading from inoculated florets to the adjacent spikelets through rachis. Deletion of PEX5 and PEX6 dropped survivability of aged cells in planta and in vitro due to the accumulation of ROS followed by necrotic cell death. These results demonstrate that PTS1-dependent peroxisomal protein import mediated by PEX5 and PEX6 are critical to virulence and survival of F. graminearum.

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27

Mastalski, Thomas, Rebecca Brinkmeier y Harald W. Platta. "The Peroxisomal PTS1-Import Defect of PEX1- Deficient Cells Is Independent of Pexophagy in Saccharomyces cerevisiae". International Journal of Molecular Sciences 21, n.º 3 (29 de enero de 2020): 867. http://dx.doi.org/10.3390/ijms21030867.

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The important physiologic role of peroxisomes is shown by the occurrence of peroxisomal biogenesis disorders (PBDs) in humans. This spectrum of autosomal recessive metabolic disorders is characterized by defective peroxisome assembly and impaired peroxisomal functions. PBDs are caused by mutations in the peroxisomal biogenesis factors, which are required for the correct compartmentalization of peroxisomal matrix enzymes. Recent work from patient cells that contain the Pex1(G843D) point mutant suggested that the inhibition of the lysosome, and therefore the block of pexophagy, was beneficial for peroxisomal function. The resulting working model proposed that Pex1 may not be essential for matrix protein import at all, but rather for the prevention of pexophagy. Thus, the observed matrix protein import defect would not be caused by a lack of Pex1 activity, but rather by enhanced removal of peroxisomal membranes via pexophagy. In the present study, we can show that the specific block of PEX1 deletion-induced pexophagy does not restore peroxisomal matrix protein import or the peroxisomal function in beta-oxidation in yeast. Therefore, we conclude that Pex1 is directly and essentially involved in peroxisomal matrix protein import, and that the PEX1 deletion-induced pexophagy is not responsible for the defect in peroxisomal function. In order to point out the conserved mechanism, we discuss our findings in the context of the working models of peroxisomal biogenesis and pexophagy in yeasts and mammals.

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Rinaldi, Mauro A., Wendell A. Fleming, Kim L. Gonzalez, Jaeseok Park, Meredith J. Ventura, Ashish B. Patel y Bonnie Bartel. "The PEX1 ATPase Stabilizes PEX6 and Plays Essential Roles in Peroxisome Biology". Plant Physiology 174, n.º 4 (9 de junio de 2017): 2231–47. http://dx.doi.org/10.1104/pp.17.00548.

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Pedrosa, Ana G., Tânia Francisco, Diana Bicho, Ana F. Dias, Aurora Barros-Barbosa, Vera Hagmann, Gabriele Dodt, Tony A. Rodrigues y Jorge E. Azevedo. "Peroxisomal monoubiquitinated PEX5 interacts with the AAA ATPases PEX1 and PEX6 and is unfolded during its dislocation into the cytosol". Journal of Biological Chemistry 293, n.º 29 (8 de junio de 2018): 11553–63. http://dx.doi.org/10.1074/jbc.ra118.003669.

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Walter, Claudia, Jeannette Gootjes, Petra A. Mooijer, Herma Portsteffen, Christina Klein, Hans R. Waterham, Peter G. Barth et al. "Disorders of Peroxisome Biogenesis Due to Mutations in PEX1: Phenotypes and PEX1 Protein Levels". American Journal of Human Genetics 69, n.º 1 (julio de 2001): 35–48. http://dx.doi.org/10.1086/321265.

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31

Tan, Dongyan, Neil B. Blok, Tom A. Rapoport y Thomas Walz. "Structures of the double-ring AAA ATPase Pex1-Pex6 involved in peroxisome biogenesis". FEBS Journal 283, n.º 6 (12 de noviembre de 2015): 986–92. http://dx.doi.org/10.1111/febs.13569.

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SKONECZNY, Marek y Joanna RYTKA. "Oxygen and haem regulate the synthesis of peroxisomal proteins: catalase A, acyl-CoA oxidase and Pex1p in the yeast Saccharomyces cerevisiae; the regulation of these proteins by oxygen is not mediated by haem". Biochemical Journal 350, n.º 1 (9 de agosto de 2000): 313–19. http://dx.doi.org/10.1042/bj3500313.

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Saccharomyces cerevisiae genes related to respiration are typically controlled by oxygen and haem. Usually the regulation by these factors is co-ordinated; haem is indicated as the oxygen sensor. However, the responsiveness of peroxisome functions to these regulatory factors is poorly understood. The expression of CTA1, POX1 and PEX1 genes encoding the peroxisomal proteins catalase A, acyl-CoA oxidase and Pex1p peroxin respectively was studied under various conditions: in anaerobiosis, in the absence of haem and in respiratory incompetence caused by the lack of a mitochondrial genome (ρ0). The influence of haem deficiency or ρ0 on peroxisomal morphology was also investigated. Respiratory incompetence has no effect on the expression of CTA1 and POX1, whereas in the absence of haem their expression is markedly decreased. The synthesis of Pex1p is decreased in ρ0 cells and is decreased even more in haem-deficient cells. Nevertheless, peroxisomal morphology in both these types of cell does not differ significantly from the morphology of peroxisomes in wild-type cells. The down-regulating effect of anoxia on the expression of CTA1 and POX1 is even stronger than the effect of haem deficiency and is not reversed by the addition of exogenous haem or the presence of endogenous haem. Moreover, neither of these genes responds to the known haem-controlled transcriptional factor Hap1p. In contrast with the other two genes studied, PEX1 is up-regulated in anaerobiosis. The existence of one or more novel mechanisms of regulation of peroxisomal genes by haem and oxygen, different from those already known in S. cerevisiae, is postulated.

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Kiel, J. A. K. W., R. E. Hilbrands, R. A. L. Bovenberg y M. Veenhuis. "Isolation of Penicillium chrysogenum PEX1 and PEX6 encoding AAA proteins involved in peroxisome biogenesis". Applied Microbiology and Biotechnology 54, n.º 2 (15 de agosto de 2000): 238–42. http://dx.doi.org/10.1007/s002530000378.

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Di Pietro, Erminia, Catherine Argyriou, Panteha Saberian, Ellen Crushell, Steven Steinberg, Yasmin D’Souza y Nancy Braverman. "A PEX1 terminal deletion retains partial PEX1 protein function resulting in an attenuated Zellweger spectrum phenotype". Molecular Genetics and Metabolism 132 (abril de 2021): S164. http://dx.doi.org/10.1016/s1096-7192(21)00344-9.

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Mbekeani, Alison, Will Stanley, Vishal Kalel, Noa Dahan, Einat Zalckvar, Lilach Sheiner, Wolfgang Schliebs, Ralf Erdmann, Ehmke Pohl y Paul Denny. "Functional Analyses of a Putative, Membrane-Bound, Peroxisomal Protein Import Mechanism from the Apicomplexan Protozoan Toxoplasma gondii". Genes 9, n.º 9 (29 de agosto de 2018): 434. http://dx.doi.org/10.3390/genes9090434.

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Peroxisomes are central to eukaryotic metabolism, including the oxidation of fatty acids—which subsequently provide an important source of metabolic energy—and in the biosynthesis of cholesterol and plasmalogens. However, the presence and nature of peroxisomes in the parasitic apicomplexan protozoa remains controversial. A survey of the available genomes revealed that genes encoding peroxisome biogenesis factors, so-called peroxins (Pex), are only present in a subset of these parasites, the coccidia. The basic principle of peroxisomal protein import is evolutionarily conserved, proteins harbouring a peroxisomal-targeting signal 1 (PTS1) interact in the cytosol with the shuttling receptor Pex5 and are then imported into the peroxisome via the membrane-bound protein complex formed by Pex13 and Pex14. Surprisingly, whilst Pex5 is clearly identifiable, Pex13 and, perhaps, Pex14 are apparently absent from the coccidian genomes. To investigate the functionality of the PTS1 import mechanism in these parasites, expression of Pex5 from the model coccidian Toxoplasma gondii was shown to rescue the import defect of Pex5-deleted Saccharomyces cerevisiae. In support of these data, green fluorescent protein (GFP) bearing the enhanced (e)PTS1 known to efficiently localise to peroxisomes in yeast, localised to peroxisome-like bodies when expressed in Toxoplasma. Furthermore, the PTS1-binding domain of Pex5 and a PTS1 ligand from the putatively peroxisome-localised Toxoplasma sterol carrier protein (SCP2) were shown to interact in vitro. Taken together, these data demonstrate that the Pex5–PTS1 interaction is functional in the coccidia and indicate that a nonconventional peroxisomal import mechanism may operate in the absence of Pex13 and Pex14.

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Goto, Shino, Shoji Mano, Chihiro Nakamori y Mikio Nishimura. "Arabidopsis ABERRANT PEROXISOME MORPHOLOGY9 Is a Peroxin That Recruits the PEX1-PEX6 Complex to Peroxisomes". Plant Cell 23, n.º 4 (abril de 2011): 1573–87. http://dx.doi.org/10.1105/tpc.110.080770.

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Gardner, Brooke M., Saikat Chowdhury, Gabriel C. Lander y Andreas Martin. "The Pex1/Pex6 Complex Is a Heterohexameric AAA + Motor with Alternating and Highly Coordinated Subunits". Journal of Molecular Biology 427, n.º 6 (marzo de 2015): 1375–88. http://dx.doi.org/10.1016/j.jmb.2015.01.019.

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38

Ratbi, Ilham, Kim D. Falkenberg, Manou Sommen, Nada Al-Sheqaih, Soukaina Guaoua, Geert Vandeweyer, Jill E. Urquhart et al. "Heimler Syndrome Is Caused by Hypomorphic Mutations in the Peroxisome-Biogenesis Genes PEX1 and PEX6". American Journal of Human Genetics 97, n.º 4 (octubre de 2015): 535–45. http://dx.doi.org/10.1016/j.ajhg.2015.08.011.

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39

Pedrosa, Ana G., Tânia Francisco, Maria J. Ferreira, Tony A. Rodrigues, Aurora Barros-Barbosa y Jorge E. Azevedo. "A Mechanistic Perspective on PEX1 and PEX6, Two AAA+ Proteins of the Peroxisomal Protein Import Machinery". International Journal of Molecular Sciences 20, n.º 21 (23 de octubre de 2019): 5246. http://dx.doi.org/10.3390/ijms20215246.

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In contrast to many protein translocases that use ATP or GTP hydrolysis as the driving force to transport proteins across biological membranes, the peroxisomal matrix protein import machinery relies on a regulated self-assembly mechanism for this purpose and uses ATP hydrolysis only to reset its components. The ATP-dependent protein complex in charge of resetting this machinery—the Receptor Export Module (REM)—comprises two members of the “ATPases Associated with diverse cellular Activities” (AAA+) family, PEX1 and PEX6, and a membrane protein that anchors the ATPases to the organelle membrane. In recent years, a large amount of data on the structure/function of the REM complex has become available. Here, we discuss the main findings and their mechanistic implications.

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40

Michelakakis, Helen M., Dimitrios I. Zafeiriou, Marina S. Moraitou, Jeannette Gootjes y Ronald J. A. Wanders. "PEX1 deficiency presenting as Leber congenital amaurosis". Pediatric Neurology 31, n.º 2 (agosto de 2004): 146–49. http://dx.doi.org/10.1016/j.pediatrneurol.2004.01.013.

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Gunduz, Mehmet y Ozlem Unal. "Dysmorphic Facial Features and Other Clinical Characteristics in Two Patients with PEX1 Gene Mutations". Case Reports in Pediatrics 2016 (2016): 1–5. http://dx.doi.org/10.1155/2016/5175709.

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Peroxisomal disorders are a group of genetically heterogeneous metabolic diseases related to dysfunction of peroxisomes. Dysmorphic features, neurological abnormalities, and hepatic dysfunction can be presenting signs of peroxisomal disorders. Here we presented dysmorphic facial features and other clinical characteristics in two patients with PEX1 gene mutation. Follow-up periods were 3.5 years and 1 year in the patients. Case I was one-year-old girl that presented with neurodevelopmental delay, hepatomegaly, bilateral hearing loss, and visual problems. Ophthalmologic examination suggested septooptic dysplasia. Cranial magnetic resonance imaging (MRI) showed nonspecific gliosis at subcortical and periventricular deep white matter. Case II was 2.5-year-old girl referred for investigation of global developmental delay and elevated liver enzymes. Ophthalmologic examination findings were consistent with bilateral nystagmus and retinitis pigmentosa. Cranial MRI was normal. Dysmorphic facial features including broad nasal root, low set ears, downward slanting eyes, downward slanting eyebrows, and epichantal folds were common findings in two patients. Molecular genetic analysis indicated homozygous novel IVS1-2A>G mutation in Case I and homozygous p.G843D (c.2528G>A) mutation in Case II in the PEX1 gene. Clinical findings and developmental prognosis vary in PEX1 gene mutation. Kabuki-like phenotype associated with liver pathology may indicate Zellweger spectrum disorders (ZSD).

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42

Guerrero-Solano, José Antonio, Mirandeli Bautista, Josué Vidal Espinosa-Juárez, Luis Alfonso Moreno-Rocha, Gabriel Betanzos-Cabrera, Liana Claudia Salanță, Minarda De la O Arciniega, Elena G. Olvera-Hernández y Osmar Antonio Jaramillo-Morales. "Differential Antinociceptive Efficacy of Peel Extracts and Lyophilized Juices of Three Varieties of Mexican Pomegranate (Punica granatum L.) in the Formalin Test". Plants 12, n.º 1 (27 de diciembre de 2022): 131. http://dx.doi.org/10.3390/plants12010131.

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Pharmacological treatment of pain often causes undesirable effects, so it is necessary to look for natural, safe, and effective alternatives to alleviate painful behavior. In this context, it is known that different parts of pomegranate have been widely consumed and used as preventive and therapeutic agents since ancient times. For example, it has been shown to have an antinociceptive effect, however, there are many varieties. Each part has been found to display unique and attractive pharmacological activities. The content of the active phytochemicals in pomegranate depends on the cultivar, geographical region, the maturity, and the processing method. In this context, the effects of various pomegranate varieties and other parts of the pomegranate (e.g., peel and juice) on pain behavior have not been examined. The aim was to evaluate and compare the antinociceptive effect of ethanolic extracts (PEx) and lyophilized juices (Lj) of three varieties of pomegranate in the formalin test. In addition, computer-aided analysis was performed for determining biological effects and toxicity. Peels were extracted with ethanol and evaporated by rotary evaporation, and juices were filtered and lyophilized. Wistar rats (N = 48) were randomly distributed into 8 groups (n = 6) (Vehicle, Acetylsalicylic Acid, PEx1, PEx2, PEx3, Lj1, Lj2, and Lj3). The formalin test (2%) was carried out, which consists of administering formalin in paw and counting the paw flinches for 1 h, with prior administration of treatments. All samples have an antinociceptive effect (phase 1: 2.8–10%; phase 2: 23.2–45.2%). PEx2 and Lj2 had the greatest antinociceptive effect (57.8–58.9%), and bioactive compounds such as tannins and flavonoids showed promising pharmacodynamic properties that may be involved in the antinociceptive effect, and can be considered as a natural alternative for the treatment of nociceptive and inflammatory pain.

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Imamura, Atsushi, Nobuyuki Shimozawa, Yasuyuki Suzuki, Zhongyi Zhang, Toshiro Tsukamoto, Yukio Fujiki, Tadao Orii, Takashi Osumi, Ronald J. A. Wanders y Naomi Kondo. "Temperature-Sensitive Mutation of PEX6 in Peroxisome Biogenesis Disorders in Complementation Group C (CG-C): Comparative Study of PEX6 and PEX1". Pediatric Research 48, n.º 4 (octubre de 2000): 541–45. http://dx.doi.org/10.1203/00006450-200010000-00020.

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Shiozawa, Kumiko, Nobuo Maita, Kentaro Tomii, Azusa Seto, Natsuko Goda, Yutaka Akiyama, Toshiyuki Shimizu, Masahiro Shirakawa y Hidekazu Hiroaki. "Crystallographic characterization of the N-terminal domain of PEX1". Acta Crystallographica Section D Biological Crystallography 60, n.º 11 (20 de octubre de 2004): 2098–99. http://dx.doi.org/10.1107/s090744490402428x.

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Galiani, Silvia, Dominic Waithe, Katharina Reglinski, Luis Daniel Cruz-Zaragoza, Esther Garcia, Mathias P. Clausen, Wolfgang Schliebs, Ralf Erdmann y Christian Eggeling. "Super-resolution Microscopy Reveals Compartmentalization of Peroxisomal Membrane Proteins". Journal of Biological Chemistry 291, n.º 33 (16 de junio de 2016): 16948–62. http://dx.doi.org/10.1074/jbc.m116.734038.

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Membrane-associated events during peroxisomal protein import processes play an essential role in peroxisome functionality. Many details of these processes are not known due to missing spatial resolution of technologies capable of investigating peroxisomes directly in the cell. Here, we present the use of super-resolution optical stimulated emission depletion microscopy to investigate with sub-60-nm resolution the heterogeneous spatial organization of the peroxisomal proteins PEX5, PEX14, and PEX11 around actively importing peroxisomes, showing distinct differences between these peroxins. Moreover, imported protein sterol carrier protein 2 (SCP2) occupies only a subregion of larger peroxisomes, highlighting the heterogeneous distribution of proteins even within the peroxisome. Finally, our data reveal subpopulations of peroxisomes showing only weak colocalization between PEX14 and PEX5 or PEX11 but at the same time a clear compartmentalized organization. This compartmentalization, which was less evident in cases of strong colocalization, indicates dynamic protein reorganization linked to changes occurring in the peroxisomes. Through the use of multicolor stimulated emission depletion microscopy, we have been able to characterize peroxisomes and their constituents to a yet unseen level of detail while maintaining a highly statistical approach, paving the way for equally complex biological studies in the future.

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46

Pan, Ronghui, John Satkovich y Jianping Hu. "E3 ubiquitin ligase SP1 regulates peroxisome biogenesis in Arabidopsis". Proceedings of the National Academy of Sciences 113, n.º 46 (31 de octubre de 2016): E7307—E7316. http://dx.doi.org/10.1073/pnas.1613530113.

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Peroxisomes are ubiquitous eukaryotic organelles that play pivotal roles in a suite of metabolic processes and often act coordinately with other organelles, such as chloroplasts and mitochondria. Peroxisomes import proteins to the peroxisome matrix by peroxins (PEX proteins), but how the function of the PEX proteins is regulated is poorly understood. In this study, we identified the Arabidopsis RING (really interesting new gene) type E3 ubiquitin ligase SP1 [suppressor of plastid protein import locus 1 (ppi1) 1] as a peroxisome membrane protein with a regulatory role in peroxisome protein import. SP1 interacts physically with the two components of the peroxisome protein docking complex PEX13–PEX14 and the (RING)-finger peroxin PEX2. Loss of SP1 function suppresses defects of the pex14-2 and pex13-1 mutants, and SP1 is involved in the degradation of PEX13 and possibly PEX14 and all three RING peroxins. An in vivo ubiquitination assay showed that SP1 has the ability to promote PEX13 ubiquitination. Our study has revealed that, in addition to its previously reported function in chloroplast biogenesis, SP1 plays a role in peroxisome biogenesis. The same E3 ubiquitin ligase promotes the destabilization of components of two distinct protein-import machineries, indicating that degradation of organelle biogenesis factors by the ubiquitin–proteasome system may constitute an important regulatory mechanism in coordinating the biogenesis of metabolically linked organelles in eukaryotes.

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47

TAMURA, Shigehiko, Naomi MATSUMOTO, Atsushi IMAMURA, Nobuyuki SHIMOZAWA, Yasuyuki SUZUKI, Naomi KONDO y Yukio FUJIKI. "Phenotype‒genotype relationships in peroxisome biogenesis disorders of PEX1-defective complementation group 1 are defined by Pex1p‒Pex6p interaction". Biochemical Journal 357, n.º 2 (15 de julio de 2001): 417. http://dx.doi.org/10.1042/0264-6021:3570417.

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48

Park, Na Yeon, Doo Sin Jo, So Jung Park, Heejin Lee, Ji-Eun Bae, Youlim Hong, Joon Bum Kim et al. "Depletion of HNRNPA1 induces peroxisomal autophagy by regulating PEX1 expression". Biochemical and Biophysical Research Communications 545 (marzo de 2021): 69–74. http://dx.doi.org/10.1016/j.bbrc.2021.01.083.

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49

Zhang, R., L. Chen, S. Jiralerspong, A. Snowden, S. Steinberg y N. Braverman. "Recovery of PEX1-Gly843Asp peroxisome dysfunction by small-molecule compounds". Proceedings of the National Academy of Sciences 107, n.º 12 (8 de marzo de 2010): 5569–74. http://dx.doi.org/10.1073/pnas.0914960107.

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50

Shiozawa, K., N. Maita, K. Tomii, A. Seto, N. Goda, Y. Akiyama, T. Shimizu, M. Shirakawa y H. Hiroaki. "Structure of the N-terminal domain of PEX1 AAA-ATPase". Acta Crystallographica Section A Foundations of Crystallography 61, a1 (23 de agosto de 2005): c268. http://dx.doi.org/10.1107/s0108767305088574.

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