1
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Mahadevan L, Arya H, Droste A, Schliebs W, Erdmann R, Kalel VC. PEX1 is essential for glycosome biogenesis and trypanosomatid parasite survival. Front Cell Infect Microbiol 2024; 14:1274506. [PMID: 38510966 PMCID: PMC10952002 DOI: 10.3389/fcimb.2024.1274506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 02/09/2024] [Indexed: 03/22/2024] Open
Abstract
Trypanosomatid parasites are kinetoplastid protists that compartmentalize glycolytic enzymes in unique peroxisome-related organelles called glycosomes. The heterohexameric AAA-ATPase complex of PEX1-PEX6 is anchored to the peroxisomal membrane and functions in the export of matrix protein import receptor PEX5 from the peroxisomal membrane. Defects in PEX1, PEX6 or their membrane anchor causes dysfunction of peroxisomal matrix protein import cycle. In this study, we functionally characterized a putative Trypanosoma PEX1 orthologue by bioinformatic and experimental approaches and show that it is a true PEX1 orthologue. Using yeast two-hybrid analysis, we demonstrate that TbPEX1 can bind to TbPEX6. Endogenously tagged TbPEX1 localizes to glycosomes in the T. brucei parasites. Depletion of PEX1 gene expression by RNA interference causes lethality to the bloodstream form trypanosomes, due to a partial mislocalization of glycosomal enzymes to the cytosol and ATP depletion. TbPEX1 RNAi leads to a selective proteasomal degradation of both matrix protein import receptors TbPEX5 and TbPEX7. Unlike in yeast, PEX1 depletion did not result in an accumulation of ubiquitinated TbPEX5 in trypanosomes. As PEX1 turned out to be essential for trypanosomatid parasites, it could provide a suitable drug target for parasitic diseases. The results also suggest that these parasites possess a highly efficient quality control mechanism that exports the import receptors from glycosomes to the cytosol in the absence of a functional TbPEX1-TbPEX6 complex.
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Affiliation(s)
| | | | | | | | - Ralf Erdmann
- Department of Systems Biochemistry, Faculty of Medicine, Institute for Biochemistry and Pathobiochemistry, Ruhr University Bochum, Bochum, Germany
| | - Vishal C. Kalel
- Department of Systems Biochemistry, Faculty of Medicine, Institute for Biochemistry and Pathobiochemistry, Ruhr University Bochum, Bochum, Germany
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2
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Francisco T, Pedrosa AG, Rodrigues TA, Abalkhail T, Li H, Ferreira MJ, van der Heden van Noort GJ, Fransen M, Hettema EH, Azevedo JE. Noncanonical and reversible cysteine ubiquitination prevents the overubiquitination of PEX5 at the peroxisomal membrane. PLoS Biol 2024; 22:e3002567. [PMID: 38470934 PMCID: PMC10959387 DOI: 10.1371/journal.pbio.3002567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 03/22/2024] [Accepted: 02/27/2024] [Indexed: 03/14/2024] Open
Abstract
PEX5, the peroxisomal protein shuttling receptor, binds newly synthesized proteins in the cytosol and transports them to the organelle. During its stay at the peroxisomal protein translocon, PEX5 is monoubiquitinated at its cysteine 11 residue, a mandatory modification for its subsequent ATP-dependent extraction back into the cytosol. The reason why a cysteine and not a lysine residue is the ubiquitin acceptor is unknown. Using an established rat liver-based cell-free in vitro system, we found that, in contrast to wild-type PEX5, a PEX5 protein possessing a lysine at position 11 is polyubiquitinated at the peroxisomal membrane, a modification that negatively interferes with the extraction process. Wild-type PEX5 cannot retain a polyubiquitin chain because ubiquitination at cysteine 11 is a reversible reaction, with the E2-mediated deubiquitination step presenting faster kinetics than PEX5 polyubiquitination. We propose that the reversible nonconventional ubiquitination of PEX5 ensures that neither the peroxisomal protein translocon becomes obstructed with polyubiquitinated PEX5 nor is PEX5 targeted for proteasomal degradation.
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Affiliation(s)
- Tânia Francisco
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal
- Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
- Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Ana G. Pedrosa
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal
- Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
- Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Tony A. Rodrigues
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal
- Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
- Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Tarad Abalkhail
- School of Biosciences, University of Sheffield, Sheffield, United Kingdom
| | - Hongli Li
- Laboratory of Peroxisome Biology and Intracellular Communication, Department of Cellular and Molecular Medicine, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Maria J. Ferreira
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal
- Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
- Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | | | - Marc Fransen
- Laboratory of Peroxisome Biology and Intracellular Communication, Department of Cellular and Molecular Medicine, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Ewald H. Hettema
- School of Biosciences, University of Sheffield, Sheffield, United Kingdom
| | - Jorge E. Azevedo
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal
- Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
- Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
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3
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Liu C, Bi Z, Xu H, Zhang R, Wang J, Liang Y, Zhang L, Yu J. Regulatory Mechanism of Peroxisome Number Reduction Caused by FgPex4 and FgPex22-like Deletion in Fusarium graminearum. J Fungi (Basel) 2023; 9:1083. [PMID: 37998888 PMCID: PMC10672079 DOI: 10.3390/jof9111083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 11/01/2023] [Accepted: 11/02/2023] [Indexed: 11/25/2023] Open
Abstract
Peroxisomes are single-membrane-bound organelles that play critical roles in eukaryotic cellular functions. Peroxisome quantity is a key factor influencing the homeostasis and pathogenic processes of pathogenic fungi. The aim of the present study was to investigate the underlying mechanisms of the reduction in number of peroxisomes in Fusarium graminearum consequent to FgPex4 and FgPex22-like deletion. The number of peroxisomes decreased by 40.55% and 39.70% when FgPex4 and FgPex22-like, respectively, were absent. Peroxisome biogenesis-related proteins, as well as inheritance- and division-related dynamin-like proteins were reduced at the transcriptional level in the mutant strains. In addition, the degree of pexophagy was intensified and the accumulation of ubiquitinated FgPex5 was also increased in F. graminearum when FgPex4 or FgPex22-like was absent. The findings suggest that FgPex4 and FgPex22-like influence the number of peroxisomes by influencing peroxisome biogenesis and pexophagy.
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Affiliation(s)
| | | | | | | | | | | | - Li Zhang
- Key Laboratory of Agricultural Microbiology, College of Plant Protection, Shandong Agricultural University, Tai’an 271018, China; (C.L.); (Z.B.); (H.X.); (R.Z.); (J.W.); (Y.L.)
| | - Jinfeng Yu
- Key Laboratory of Agricultural Microbiology, College of Plant Protection, Shandong Agricultural University, Tai’an 271018, China; (C.L.); (Z.B.); (H.X.); (R.Z.); (J.W.); (Y.L.)
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4
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Abstract
Peroxisomes are involved in a multitude of metabolic and catabolic pathways, as well as the innate immune system. Their dysfunction is linked to severe peroxisome-specific diseases, as well as cancer and neurodegenerative diseases. To ensure the ability of peroxisomes to fulfill their many roles in the organism, more than 100 different proteins are post-translationally imported into the peroxisomal membrane and matrix, and their functionality must be closely monitored. In this Review, we briefly discuss the import of peroxisomal membrane proteins, and we emphasize an updated view of both classical and alternative peroxisomal matrix protein import pathways. We highlight different quality control pathways that ensure the degradation of dysfunctional peroxisomal proteins. Finally, we compare peroxisomal matrix protein import with other systems that transport folded proteins across membranes, in particular the twin-arginine translocation (Tat) system and the nuclear pore.
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Affiliation(s)
- Markus Rudowitz
- Systems Biochemistry , Institute of Biochemistry and Pathobiochemistry, Faculty of Medicine, Ruhr University Bochum, Universitätsstr. 150, 44801 Bochum, Germany
| | - Ralf Erdmann
- Systems Biochemistry , Institute of Biochemistry and Pathobiochemistry, Faculty of Medicine, Ruhr University Bochum, Universitätsstr. 150, 44801 Bochum, Germany
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5
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Fischer S, Bürgi J, Gabay-Maskit S, Maier R, Mastalski T, Yifrach E, Obarska-Kosinska A, Rudowitz M, Erdmann R, Platta HW, Wilmanns M, Schuldiner M, Zalckvar E, Oeljeklaus S, Drepper F, Warscheid B. Phosphorylation of the receptor protein Pex5p modulates import of proteins into peroxisomes. Biol Chem 2023; 404:135-155. [PMID: 36122347 PMCID: PMC9929924 DOI: 10.1515/hsz-2022-0168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 08/23/2022] [Indexed: 11/15/2022]
Abstract
Peroxisomes are organelles with vital functions in metabolism and their dysfunction is associated with human diseases. To fulfill their multiple roles, peroxisomes import nuclear-encoded matrix proteins, most carrying a peroxisomal targeting signal (PTS) 1. The receptor Pex5p recruits PTS1-proteins for import into peroxisomes; whether and how this process is posttranslationally regulated is unknown. Here, we identify 22 phosphorylation sites of Pex5p. Yeast cells expressing phospho-mimicking Pex5p-S507/523D (Pex5p2D) show decreased import of GFP with a PTS1. We show that the binding affinity between a PTS1-protein and Pex5p2D is reduced. An in vivo analysis of the effect of the phospho-mimicking mutant on PTS1-proteins revealed that import of most, but not all, cargos is affected. The physiological effect of the phosphomimetic mutations correlates with the binding affinity of the corresponding extended PTS1-sequences. Thus, we report a novel Pex5p phosphorylation-dependent mechanism for regulating PTS1-protein import into peroxisomes. In a broader view, this suggests that posttranslational modifications can function in fine-tuning the peroxisomal protein composition and, thus, cellular metabolism.
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Affiliation(s)
- Sven Fischer
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, Schänzlestrasse 1, D-79104Freiburg, Germany
| | - Jérôme Bürgi
- Hamburg Unit c/o DESY, European Molecular Biology Laboratory (EMBL), Notkestrasse 85, D-22607Hamburg, Germany
- University Medical Center Hamburg-Eppendorf, Martinistrasse 52, D-20246Hamburg, Germany
| | - Shiran Gabay-Maskit
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot7610001, Israel
| | - Renate Maier
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, Schänzlestrasse 1, D-79104Freiburg, Germany
| | - Thomas Mastalski
- Biochemistry of Intracellular Transport, Medical Faculty, Ruhr University Bochum, D-44780Bochum, Germany
| | - Eden Yifrach
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot7610001, Israel
| | - Agnieszka Obarska-Kosinska
- Hamburg Unit c/o DESY, European Molecular Biology Laboratory (EMBL), Notkestrasse 85, D-22607Hamburg, Germany
- University Medical Center Hamburg-Eppendorf, Martinistrasse 52, D-20246Hamburg, Germany
| | - Markus Rudowitz
- Systems Biochemistry, Medical Faculty, Ruhr-University Bochum, D-44780Bochum, Germany
| | - Ralf Erdmann
- Systems Biochemistry, Medical Faculty, Ruhr-University Bochum, D-44780Bochum, Germany
| | - Harald W. Platta
- Biochemistry of Intracellular Transport, Medical Faculty, Ruhr University Bochum, D-44780Bochum, Germany
| | - Matthias Wilmanns
- Hamburg Unit c/o DESY, European Molecular Biology Laboratory (EMBL), Notkestrasse 85, D-22607Hamburg, Germany
- University Medical Center Hamburg-Eppendorf, Martinistrasse 52, D-20246Hamburg, Germany
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot7610001, Israel
| | - Einat Zalckvar
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot7610001, Israel
| | - Silke Oeljeklaus
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, Schänzlestrasse 1, D-79104Freiburg, Germany
- Biochemistry II, Theodor Boveri-Institute, Biocenter, University of Würzburg, Am Hubland, D-97074, Würzburg, Germany
| | - Friedel Drepper
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, Schänzlestrasse 1, D-79104Freiburg, Germany
| | - Bettina Warscheid
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, Schänzlestrasse 1, D-79104Freiburg, Germany
- Biochemistry II, Theodor Boveri-Institute, Biocenter, University of Würzburg, Am Hubland, D-97074, Würzburg, Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, D-79104Freiburg, Germany
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6
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Anteghini M, Martins Dos Santos VAP. Computational Approaches for Peroxisomal Protein Localization. Methods Mol Biol 2023; 2643:405-411. [PMID: 36952202 DOI: 10.1007/978-1-0716-3048-8_29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/24/2023]
Abstract
Computational approaches are practical when investigating putative peroxisomal proteins and for sub-peroxisomal protein localization in unknown protein sequences. Nowadays, advancements in computational methods and Machine Learning (ML) can be used to hasten the discovery of novel peroxisomal proteins and can be combined with more established computational methodologies. Here, we explain and list some of the most used tools and methodologies for novel peroxisomal protein detection and localization.
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Affiliation(s)
- Marco Anteghini
- Lifeglimmer GmbH, Berlin, Germany.
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Wageningen, WE, The Netherlands.
- Zuse Institut Berlin, Visual and Data-Centric Computing, Berlin, Germany.
| | - Vitor A P Martins Dos Santos
- Lifeglimmer GmbH, Berlin, Germany
- BioProcess Engineering, Wageningen University & Research, Wageningen, WE, The Netherlands
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7
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Demers ND, Riccio V, Jo DS, Bhandari S, Law KB, Liao W, Kim C, McQuibban GA, Choe SK, Cho DH, Kim PK. PEX13 prevents pexophagy by regulating ubiquitinated PEX5 and peroxisomal ROS. Autophagy 2023:1-22. [PMID: 36541703 DOI: 10.1080/15548627.2022.2160566] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Peroxisomes are rapidly degraded during amino acid and oxygen deprivation by a type of selective autophagy called pexophagy. However, how damaged peroxisomes are detected and removed from the cell is poorly understood. Recent studies suggest that the peroxisomal matrix protein import machinery may serve double duty as a quality control machinery, where they are directly involved in activating pexophagy. Here, we explored whether any matrix import factors are required to prevent pexophagy, such that their loss designates peroxisomes for degradation. Using gene editing and quantitative fluorescence microscopy on culture cells and a zebrafish model system, we found that PEX13, a component of the peroxisomal matrix import system, is required to prevent the degradation of otherwise healthy peroxisomes. The loss of PEX13 caused an accumulation of ubiquitinated PEX5 on peroxisomes and an increase in peroxisome-dependent reactive oxygen species that coalesce to induce pexophagy. We also found that PEX13 protein level is downregulated to aid in the induction of pexophagy during amino acid starvation. Together, our study points to PEX13 as a novel pexophagy regulator that is modulated to maintain peroxisome homeostasis.Abbreviations: AAA ATPases: ATPases associated with diverse cellular activities; ABCD3: ATP binding cassette subfamily D member; 3ACOX1: acyl-CoA oxidase; 1ACTA1: actin alpha 1, skeletal muscle; ACTB: actin beta; ATG5: autophagy related 5; ATG7: autophagy related 7; ATG12: autophagy related 12; ATG16L1: autophagy related 16 like 1; CAT: catalase; CQ: chloroquine; Dpf: days post fertilization: FBS: fetal bovine serum; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GFP: green fluorescent protein; H2O2: hydrogen peroxide; HA - human influenza hemagglutinin; HBSS: Hanks' Balanced Salt Solution; HCQ; hydroxychloroquine; KANL: lysine alanine asparagine leucine; KO: knockout; MAP1LC3B: microtubule associated protein 1 light chain 3 beta; MEF: mouse embryonic fibroblast; MTOR: mechanistic target of rapamycin kinase; MTORC1: mechanistic target of rapamycin kinase complex 1; MTORC2: mechanistic target of rapamycin kinase complex 2; MYC: MYC proto-oncogene, bHLH transcription factor; MZ: maternal and zygotic; NAC: N-acetyl cysteine; NBR1 - NBR1 autophagy cargo receptor; PBD: peroxisome biogenesis disorder; PBS: phosphate-buffered saline; PEX: peroxisomal biogenesis factor; PTS1: peroxisome targeting sequence 1; RFP: red fluorescent protein; ROS: reactive oxygen speciess; iRNA: short interfering RNA; SKL: serine lysine leucine; SLC25A17/PMP34: solute carrier family 25 member 17; Ub: ubiquitin; USP30: ubiquitin specific peptidase 30.
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Affiliation(s)
- Nicholas D Demers
- Cell Biology Program, Hospital for Sick Children, Peter Gilgan Centre for Research and Learning, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Victoria Riccio
- Cell Biology Program, Hospital for Sick Children, Peter Gilgan Centre for Research and Learning, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Doo Sin Jo
- School of Life Sciences, BK21 Four Knu Creative BioResearch Group Kyungpook National University, Republic of Korea
| | - Sushil Bhandari
- Department of Microbiology, Wonkwang University School of Medicine, Iksan, Republic of Korea
| | - Kelsey B Law
- Cell Biology Program, Hospital for Sick Children, Peter Gilgan Centre for Research and Learning, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Weifang Liao
- Department of Microbiology, Wonkwang University School of Medicine, Iksan, Republic of Korea
| | - Choy Kim
- Department of Microbiology, Wonkwang University School of Medicine, Iksan, Republic of Korea
| | - G Angus McQuibban
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Seong-Kyu Choe
- Department of Microbiology, Wonkwang University School of Medicine, Iksan, Republic of Korea
| | - Dong-Hyung Cho
- School of Life Sciences, BK21 Four Knu Creative BioResearch Group Kyungpook National University, Republic of Korea
| | - Peter K Kim
- Cell Biology Program, Hospital for Sick Children, Peter Gilgan Centre for Research and Learning, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada.,Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology, South Korea
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8
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Mano S, Hayashi Y, Hikino K, Otomo M, Kanai M, Nishimura M. Ubiquitin-conjugating activity by PEX4 is required for efficient protein transport to peroxisomes in Arabidopsis thaliana. J Biol Chem 2022; 298:102038. [PMID: 35595097 PMCID: PMC9190015 DOI: 10.1016/j.jbc.2022.102038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 05/10/2022] [Accepted: 05/11/2022] [Indexed: 11/08/2022] Open
Abstract
Protein transport to peroxisomes requires various proteins, such as receptors in the cytosol and components of the transport machinery on peroxisomal membranes. The Arabidopsis apem (aberrant peroxisome morphology) mutant apem7 shows decreased efficiency of peroxisome targeting signal 1–dependent protein transport to peroxisomes. In apem7 mutants, peroxisome targeting signal 2–dependent protein transport is also disturbed, and plant growth is repressed. The APEM7 gene encodes a protein homologous to peroxin 4 (PEX4), which belongs to the ubiquitin-conjugating (UBC) protein family; however, the UBC activity of Arabidopsis PEX4 remains to be investigated. Here, we show using electron microscopy and immunoblot analysis using specific PEX4 antibodies and in vitro transcription/translation assay that PEX4 localizes to peroxisomal membranes and possesses UBC activity. We found that the substitution of proline with leucine by apem7 mutation alters ubiquitination of PEX4. Furthermore, substitution of the active-site cysteine residue at position 90 in PEX4, which was predicted to be a ubiquitin-conjugation site, with alanine did not restore the apem7 phenotype. Taken together, these findings indicate that abnormal ubiquitination in the apem7 mutant alters ubiquitin signaling during the process of protein transport, suggesting that the UBC activity of PEX4 is indispensable for efficient protein transport to peroxisomes.
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Affiliation(s)
- Shoji Mano
- Department of Cell Biology, National Institute for Basic Biology, Myodaiji, Okazaki, Japan; Department of Basic Biology, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Myodaiji, Okazaki, Japan.
| | - Yasuko Hayashi
- Graduate School of Science and Technology, Niigata University, Ikarashi, Niigata, Japan
| | - Kazumi Hikino
- Department of Cell Biology, National Institute for Basic Biology, Myodaiji, Okazaki, Japan
| | - Masayoshi Otomo
- Graduate School of Science and Technology, Niigata University, Ikarashi, Niigata, Japan
| | - Masatake Kanai
- Department of Cell Biology, National Institute for Basic Biology, Myodaiji, Okazaki, Japan
| | - Mikio Nishimura
- Department of Cell Biology, National Institute for Basic Biology, Myodaiji, Okazaki, Japan
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9
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Argyriou C, Polosa A, Song JY, Omri S, Steele B, Cécyre B, McDougald DS, Di Pietro E, Bouchard JF, Bennett J, Hacia JG, Lachapelle P, Braverman NE. AAV-mediated PEX1 gene augmentation improves visual function in the PEX1-Gly844Asp mouse model for mild Zellweger spectrum disorder. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2021; 23:225-240. [PMID: 34703844 PMCID: PMC8516995 DOI: 10.1016/j.omtm.2021.09.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 09/01/2021] [Indexed: 12/01/2022]
Abstract
Patients with Zellweger spectrum disorder (ZSD) commonly present with vision loss due to mutations in PEX genes required for peroxisome assembly and function. Here, we evaluate PEX1 retinal gene augmentation therapy in a mouse model of mild ZSD bearing the murine equivalent (PEX1-p[Gly844Asp]) of the most common human mutation. Experimental adeno-associated virus 8.cytomegalovirus.human PEX1.hemagglutinin (AAV8.CMV.HsPEX1.HA) and control AAV8.CMV.EGFP vectors were administered by subretinal injection in contralateral eyes of early (5-week-old)- or later (9-week-old)-stage retinopathy cohorts. HsPEX1.HA protein was expressed in the retina with no gross histologic side effects. Peroxisomal metabolic functions, assessed by retinal C26:0 lysophosphatidylcholine (lyso-PC) levels, were partially normalized after therapeutic vector treatment. Full-field flash electroretinogram (ffERG) analyses at 8 weeks post-injection showed a 2-fold improved retinal response in the therapeutic relative to control vector-injected eyes. ffERG improved by 1.6- to 2.5-fold in the therapeutic vector-injected eyes when each cohort reached 25 weeks of age. At 32 weeks of age, the average ffERG response was double in the therapeutic relative to control vector-injected eyes in both cohorts. Optomotor reflex analyses trended toward improvement. These proof-of-concept studies represent the first application of gene augmentation therapy to treat peroxisome biogenesis disorders and support the potential for retinal gene delivery to improve vision in these patients.
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Affiliation(s)
- Catherine Argyriou
- Department of Human Genetics, McGill University, Montreal, QC, Canada.,Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Anna Polosa
- Department of Ophthalmology & Visual Sciences, McGill University, Montreal, QC, Canada.,Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Ji Yun Song
- Center for Advanced Retinal and Ocular Therapeutics, F.M. Kirby Center for Molecular Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Samy Omri
- Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Bradford Steele
- Department of Biochemistry and Molecular Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Bruno Cécyre
- School of Optometry, Université de Montréal, Montreal, QC, Canada
| | - Devin S McDougald
- Center for Advanced Retinal and Ocular Therapeutics, F.M. Kirby Center for Molecular Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Erminia Di Pietro
- Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | | | - Jean Bennett
- Center for Advanced Retinal and Ocular Therapeutics, F.M. Kirby Center for Molecular Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Joseph G Hacia
- Department of Biochemistry and Molecular Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Pierre Lachapelle
- Department of Ophthalmology & Visual Sciences, McGill University, Montreal, QC, Canada.,Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Nancy E Braverman
- Department of Human Genetics, McGill University, Montreal, QC, Canada.,Research Institute of the McGill University Health Centre, Montreal, QC, Canada
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10
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Infant T, Deb R, Ghose S, Nagotu S. Post-translational modifications of proteins associated with yeast peroxisome membrane: An essential mode of regulatory mechanism. Genes Cells 2021; 26:843-860. [PMID: 34472666 PMCID: PMC9291962 DOI: 10.1111/gtc.12892] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Revised: 08/21/2021] [Accepted: 08/23/2021] [Indexed: 12/12/2022]
Abstract
Peroxisomes are single membrane‐bound organelles important for the optimum functioning of eukaryotic cells. Seminal discoveries in the field of peroxisomes are made using yeast as a model. Several proteins required for the biogenesis and function of peroxisomes are identified to date. As with proteins involved in other major cellular pathways, peroxisomal proteins are also subjected to regulatory post‐translational modifications. Identification, characterization and mapping of these modifications to specific amino acid residues on proteins are critical toward understanding their functional significance. Several studies have tried to identify post‐translational modifications of peroxisomal proteins and determine their impact on peroxisome structure and function. In this manuscript, we provide an overview of the various post‐translational modifications that govern the peroxisome dynamics in yeast.
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Affiliation(s)
- Terence Infant
- Organelle Biology and Cellular Ageing Lab, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, India
| | - Rachayeeta Deb
- Organelle Biology and Cellular Ageing Lab, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, India
| | - Suchetana Ghose
- Organelle Biology and Cellular Ageing Lab, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, India
| | - Shirisha Nagotu
- Organelle Biology and Cellular Ageing Lab, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, India
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11
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SRPassing Co-translational Targeting: The Role of the Signal Recognition Particle in Protein Targeting and mRNA Protection. Int J Mol Sci 2021; 22:ijms22126284. [PMID: 34208095 PMCID: PMC8230904 DOI: 10.3390/ijms22126284] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/02/2021] [Accepted: 06/05/2021] [Indexed: 01/13/2023] Open
Abstract
Signal recognition particle (SRP) is an RNA and protein complex that exists in all domains of life. It consists of one protein and one noncoding RNA in some bacteria. It is more complex in eukaryotes and consists of six proteins and one noncoding RNA in mammals. In the eukaryotic cytoplasm, SRP co-translationally targets proteins to the endoplasmic reticulum and prevents misfolding and aggregation of the secretory proteins in the cytoplasm. It was demonstrated recently that SRP also possesses an earlier unknown function, the protection of mRNAs of secretory proteins from degradation. In this review, we analyze the progress in studies of SRPs from different organisms, SRP biogenesis, its structure, and function in protein targeting and mRNA protection.
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Zhou J, Chen S, Shi W, David-Schwartz R, Li S, Yang F, Lin Z. Transcriptome profiling reveals the effects of drought tolerance in Giant Juncao. BMC PLANT BIOLOGY 2021; 21:2. [PMID: 33390157 PMCID: PMC7780708 DOI: 10.1186/s12870-020-02785-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 12/06/2020] [Indexed: 05/05/2023]
Abstract
BACKGROUND Giant Juncao is often used as feed for livestock because of its huge biomass. However, drought stress reduces forage production by affecting the normal growth and development of plants. Therefore, investigating the molecular mechanisms of drought tolerance will provide important information for the improvement of drought tolerance in this grass. RESULTS A total of 144.96 Gb of clean data was generated and assembled into 144,806 transcripts and 93,907 unigenes. After 7 and 14 days of drought stress, a total of 16,726 and 46,492 differentially expressed genes (DEGs) were observed, respectively. Compared with normal irrigation, 16,247, 23,503, and 11,598 DEGs were observed in 1, 5, and 9 days following rehydration, respectively. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses revealed abiotic stress-responsive genes and pathways related to catalytic activity, methyltransferase activity, transferase activity, and superoxide metabolic process. We also identified transcription factors belonging to several families, including basic helix-loop-helix (bHLH), WRKY, NAM (no apical meristem), ATAF1/2 and CUC2 (cup-shaped cotyledon) (NAC), fatty acyl-CoA reductase (FAR1), B3, myeloblastosis (MYB)-related, and basic leucine zipper (bZIP) families, which are important drought-rehydration-responsive proteins. Weighted gene co-expression network analysis was also used to analyze the RNA-seq data to predict the interrelationship between genes. Twenty modules were obtained, and four of these modules may be involved in photosynthesis and plant hormone signal transduction that respond to drought and rehydration conditions. CONCLUSIONS Our research is the first to provide a more comprehensive understanding of DEGs involved in drought stress at the transcriptome level in Giant Juncao with different drought and recovery conditions. These results may reveal insights into the molecular mechanisms of drought tolerance in Giant Juncao and provide diverse genetic resources involved in drought tolerance research.
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Affiliation(s)
- Jing Zhou
- National Engineering Research Center of Juncao, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
| | - Siqi Chen
- College of Animal Sciences (College of Bee Science), Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Wenjiao Shi
- College of Animal Sciences (College of Bee Science), Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Rakefet David-Schwartz
- Institute of Plant Sciences, Volcani Center, Agriculture Research Organization, 50250, Bet Dagan, Israel
| | - Sutao Li
- College of Animal Sciences (College of Bee Science), Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Fulin Yang
- College of Animal Sciences (College of Bee Science), Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Zhanxi Lin
- National Engineering Research Center of Juncao, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
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13
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Rudowitz M, Erdmann R, Schliebs W. Membrane Processing and Steady-State Regulation of the Alternative Peroxisomal Import Receptor Pex9p. Front Cell Dev Biol 2020; 8:566321. [PMID: 33195197 PMCID: PMC7642143 DOI: 10.3389/fcell.2020.566321] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 09/30/2020] [Indexed: 01/29/2023] Open
Abstract
Import of peroxisomal matrix proteins with a type 1 peroxisomal targeting signal (PTS1) in Saccharomyces cerevisiae is facilitated by cytosolic import receptors Pex5p and Pex9p. While Pex5p has a broad specificity for all PTS1 proteins independent of the growth conditions, Pex9p is only expressed in fatty-acid containing media to mediate peroxisomal import of the two malate synthases, Mls1p and Mls2p, as well as the glutathione transferase Gto1p. Pex5p-cargo complexes dock at the peroxisomal membrane, translocate their cargo-protein via a transient pore and are recycled into the cytosol for a further round of import. The processing of Pex5p has been shown to require a complex network of interactions with other membrane-bound peroxins, as well as decoration with ubiquitin as signal for its ATP-dependent release and recycling. Here, we show that the alternative receptor Pex9p requires the same set of interacting peroxins to mediate peroxisomal import of Mls1p. However, while Pex5p is rather stable, Pex9p is rapidly degraded during its normal life cycle. The steady-state regulation of Pex9p, combining oleate-induced expression with high turnover rates resembles that of Pex18p, one of the two co-receptors of the PTS2-dependent targeting pathway into peroxisomes. Both Pex9p- and Pex18p-dependent import routes serve the fast metabolic adaptation to changes of carbon sources in baker’s yeast. By sequence similarities, we identified another Pex9p homolog in the human pathogenic fungus Candida glabrata, in which similar metabolic reprogramming strategies are crucial for survival of the pathogen.
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Affiliation(s)
- Markus Rudowitz
- Department of Systems Biochemistry, Institute of Biochemistry and Pathobiochemistry, Ruhr-University Bochum, Bochum, Germany
| | - Ralf Erdmann
- Department of Systems Biochemistry, Institute of Biochemistry and Pathobiochemistry, Ruhr-University Bochum, Bochum, Germany
| | - Wolfgang Schliebs
- Department of Systems Biochemistry, Institute of Biochemistry and Pathobiochemistry, Ruhr-University Bochum, Bochum, Germany
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14
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Abstract
Blobel and coworkers discovered in 1978 that peroxisomal proteins are synthesized on free ribosomes in the cytosol and thus provided the grounds for the conception of peroxisomes as self-containing organelles. Peroxisomes are highly adaptive and versatile organelles carrying out a wide variety of metabolic functions. A striking feature of the peroxisomal import machinery is that proteins can traverse the peroxisomal membrane in a folded and even oligomeric state via cycling receptors. We outline essential steps of peroxisomal matrix protein import, from targeting of the proteins to the peroxisomal membrane, their translocation via transient pores and export of the corresponding cycling import receptors with emphasis on the situation in yeast. Peroxisomes can contribute to the adaptation of cells to different environmental conditions. This is realized by changes in metabolic functions and thus the enzyme composition of the organelles is adopted according to the cellular needs. In recent years, it turned out that this organellar diversity is based on an elaborate regulation of gene expression and peroxisomal protein import. The latter is in the focus of this review that summarizes our knowledge on the composition and function of the peroxisomal protein import machinery with emphasis on novel alternative protein import pathways.
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Affiliation(s)
- Thomas Walter
- Systems Biochemistry, Institute of Biochemistry and Pathobiochemistry, Faculty of Medicine, Ruhr-University Bochum, Universitätsstr. 150, 44780, Bochum, Germany
| | - Ralf Erdmann
- Systems Biochemistry, Institute of Biochemistry and Pathobiochemistry, Faculty of Medicine, Ruhr-University Bochum, Universitätsstr. 150, 44780, Bochum, Germany.
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15
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Germain K, Kim PK. Pexophagy: A Model for Selective Autophagy. Int J Mol Sci 2020; 21:ijms21020578. [PMID: 31963200 PMCID: PMC7013971 DOI: 10.3390/ijms21020578] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 01/09/2020] [Accepted: 01/13/2020] [Indexed: 01/03/2023] Open
Abstract
The removal of damaged or superfluous organelles from the cytosol by selective autophagy is required to maintain organelle function, quality control and overall cellular homeostasis. Precisely how substrate selectivity is achieved, and how individual substrates are degraded during selective autophagy in response to both extracellular and intracellular cues is not well understood. The aim of this review is to highlight pexophagy, the autophagic degradation of peroxisomes, as a model for selective autophagy. Peroxisomes are dynamic organelles whose abundance is rapidly modulated in response to metabolic demands. Peroxisomes are routinely turned over by pexophagy for organelle quality control yet can also be degraded by pexophagy in response to external stimuli such as amino acid starvation or hypoxia. This review discusses the molecular machinery and regulatory mechanisms governing substrate selectivity during both quality-control pexophagy and pexophagy in response to external stimuli, in yeast and mammalian systems. We draw lessons from pexophagy to infer how the cell may coordinate the degradation of individual substrates by selective autophagy across different cellular cues.
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Affiliation(s)
- Kyla Germain
- Cell Biology Program, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada;
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Peter K. Kim
- Cell Biology Program, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada;
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
- Correspondence: ; Tel.: +1-416-813-5983
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16
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Argyriou C, Polosa A, Cecyre B, Hsieh M, Di Pietro E, Cui W, Bouchard JF, Lachapelle P, Braverman N. A longitudinal study of retinopathy in the PEX1-Gly844Asp mouse model for mild Zellweger Spectrum Disorder. Exp Eye Res 2019; 186:107713. [PMID: 31254513 DOI: 10.1016/j.exer.2019.107713] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 05/17/2019] [Accepted: 06/25/2019] [Indexed: 02/03/2023]
Abstract
Zellweger Spectrum Disorder (ZSD) is an autosomal recessive disease caused by mutations in any one of 13 PEX genes whose protein products are required for peroxisome assembly. Retinopathy leading to blindness is one of the major untreatable handicaps faced by patients with ZSD but is not well characterized, and the requirement for peroxisomes in retinal health is unknown. To address this, we examined the progression of retinopathy from 2 to 32 weeks of age in our murine model for the common human PEX1-p.Gly843Asp allele (PEX1-p.Gly844Asp) using electrophysiology, histology, immunohistochemistry, electron microscopy, biochemistry, and visual function tests. We found that retinopathy in male and female PEX1-G844D mice was marked by an attenuated cone function and abnormal cone morphology early in life, with gradually decreasing rod function. Structural defects at the inner retina occurred later in the form of bipolar cell degradation (between 13 and 32 weeks). Inner segment disorganization and enlarged mitochondria were seen at 32 weeks, while other inner retinal cells appeared preserved. Visual acuity was diminished by 11 weeks of age, while signal transmission from the retina to the brain was relatively intact from 7 to 32 weeks of age. Molecular analyses showed that PEX1-G844D is a subfunctional but stable protein, contrary to human PEX1-G843D. Finally, C26:0 lysophosphatidylcholine was elevated in the PEX1-G844D retina, while phopshoethanolamine plasmalogen lipids were present at normal levels. These characterization studies identify therapeutic endpoints for future preclinical trials, including improving or preserving the electroretinogram response, improving visual acuity, and/or preventing loss of bipolar cells.
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Affiliation(s)
- Catherine Argyriou
- Department of Human Genetics, McGill University, Research Institute of the McGill University Health Centre, 1001 Decarie Boulevard, Montreal, Quebec, H4A 3J1, Canada.
| | - Anna Polosa
- Department of Ophthalmology, McGill University, 1001 Decarie Boulevard, Montreal, Quebec, H4A 3J1, Canada.
| | - Bruno Cecyre
- School of Optometry, Université de Montréal, Pavillon 3744 Jean-Brillant, Bureau 260-39, Montréal, Québec, H3T 1P1, Canada.
| | - Monica Hsieh
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, 1001 Decarie Boulevard, Montreal, Quebec, H4A 3J1, Canada.
| | - Erminia Di Pietro
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, 1001 Decarie Boulevard, Montreal, Quebec, H4A 3J1, Canada.
| | - Wei Cui
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, 1001 Decarie Boulevard, Montreal, Quebec, H4A 3J1, Canada.
| | - Jean-François Bouchard
- School of Optometry, Université de Montréal, Pavillon 3744 Jean-Brillant, Bureau 260-39, Montréal, Québec, H3T 1P1, Canada.
| | - Pierre Lachapelle
- Department of Ophthalmology, McGill University, 1001 Decarie Boulevard, Montreal, Quebec, H4A 3J1, Canada; Child Health and Human Development Program, Research Institute of the McGill University Health Centre, 1001 Decarie Boulevard, Montreal, Quebec, H4A 3J1, Canada.
| | - Nancy Braverman
- Department of Human Genetics, McGill University, Research Institute of the McGill University Health Centre, 1001 Decarie Boulevard, Montreal, Quebec, H4A 3J1, Canada; Child Health and Human Development Program, Research Institute of the McGill University Health Centre, 1001 Decarie Boulevard, Montreal, Quebec, H4A 3J1, Canada; Department of Pediatrics, 1001 Decarie Boulevard, Montreal, Quebec, H4A 3J1, Canada.
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17
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El Magraoui F, Brinkmeier R, Mastalski T, Hupperich A, Strehl C, Schwerter D, Girzalsky W, Meyer HE, Warscheid B, Erdmann R, Platta HW. The deubiquitination of the PTS1-import receptor Pex5p is required for peroxisomal matrix protein import. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1866:199-213. [PMID: 30408545 DOI: 10.1016/j.bbamcr.2018.11.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 10/13/2018] [Accepted: 11/02/2018] [Indexed: 12/28/2022]
Abstract
Peroxisomal biogenesis depends on the correct import of matrix proteins into the lumen of the organelle. Most peroxisomal matrix proteins harbor the peroxisomal targeting-type 1 (PTS1), which is recognized by the soluble PTS1-receptor Pex5p in the cytosol. Pex5p ferries the PTS1-proteins to the peroxisomal membrane and releases them into the lumen. Finally, the PTS1-receptor is monoubiquitinated on the conserved cysteine 6 in Saccharomyces cerevisiae. The monoubiquitinated Pex5p is recognized by the peroxisomal export machinery and is retrotranslocated into the cytosol for further rounds of protein import. However, the functional relevance of deubiquitination has not yet been addressed. In this study, we have analyzed a Pex5p-truncation lacking Cys6 [(Δ6)Pex5p], a construct with a ubiquitin-moiety genetically fused to the truncation [Ub-(Δ6)Pex5p], as well as a construct with a reduced susceptibility to deubiquitination [Ub(G75/76A)-(Δ6)Pex5p]. While the (Δ6)Pex5p-truncation is not functional, the Ub-(Δ6)Pex5p chimeric protein can facilitate matrix protein import. In contrast, the Ub(G75/76A)-(Δ6)Pex5p chimera exhibits a complete PTS1-import defect. The data show for the first time that not only ubiquitination but also deubiquitination rates are tightly regulated and that efficient deubiquitination of Pex5p is essential for peroxisomal biogenesis.
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Affiliation(s)
- Fouzi El Magraoui
- Biomedizinische Forschung, Leibniz-Insitute for Analytische Wissenschaften - ISAS e.V. - (ISAS e.V.), 44139 Dortmund, Germany; Systembiochemie, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Rebecca Brinkmeier
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Thomas Mastalski
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Alexander Hupperich
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Christofer Strehl
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | | | | | - Helmut E Meyer
- Biomedizinische Forschung, Leibniz-Insitute for Analytische Wissenschaften - ISAS e.V. - (ISAS e.V.), 44139 Dortmund, Germany
| | - Bettina Warscheid
- Functional Proteomics, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany
| | - Ralf Erdmann
- Systembiochemie, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Harald W Platta
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, 44801 Bochum, Germany.
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18
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MacLean GE, Argyriou C, Di Pietro E, Sun X, Birjandian S, Saberian P, Hacia JG, Braverman NE. Zellweger spectrum disorder patient-derived fibroblasts with the PEX1-Gly843Asp allele recover peroxisome functions in response to flavonoids. J Cell Biochem 2018; 120:3243-3258. [PMID: 30362618 DOI: 10.1002/jcb.27591] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Accepted: 08/08/2018] [Indexed: 01/03/2023]
Abstract
Zellweger spectrum disorder (ZSD) results from biallelic mutations in PEX genes required for peroxisome biogenesis. PEX1-G843D is a common hypomorphic allele in the patient population that is associated with milder disease. In prior work using a PEX1-G843D/null patient fibroblast line expressing a green fluorescent protein (GFP) reporter with a peroxisome-targeting signal (GFP-PTS1), we demonstrated that treatments with the chemical chaperone betaine and flavonoid acacetin diacetate recovered peroxisome functions. To identify more effective compounds for preclinical investigation, we evaluated 54 flavonoids using this cell-based phenotype assay. Diosmetin showed the most promising combination of potency and efficacy (EC50 2.5 µM). All active 5',7'-dihydroxyflavones showed greater average efficacy than their corresponding flavonols, whereas the corresponding flavanones, isoflavones, and chalcones tested were inactive. Additional treatment with the proteostasis regulator bortezomib increased the percentage of import-rescued cells over treatment with flavonoids alone. Cotreatments of diosmetin and betaine showed the most robust additive effects, as confirmed by three independent functional assays in primary PEX1-G843D patient cells, but neither agent was active alone or in combination in patient cells homozygous for the PEX1 c.2097_2098insT null allele. Moreover, diosmetin treatment increased PEX1, PEX6, and PEX5 protein levels in PEX1-G843D patient cells, but none of these proteins increased in PEX1 null cells. We propose that diosmetin acts as a pharmacological chaperone that improves the stability, conformation, and functions of PEX1/PEX6 exportomer complexes required for peroxisome assembly. We suggest that diosmetin, in clinical use for chronic venous disease, and related flavonoids warrant further preclinical investigation for the treatment of PEX1-G843D-associated ZSD.
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Affiliation(s)
- Gillian E MacLean
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
| | - Catherine Argyriou
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
| | - Erminia Di Pietro
- Department of Pediatrics, Research Institute of the McGill University Health Center, Montreal, Quebec, Canada
| | - Xuting Sun
- Department of Biotechnology, McGill University, Montreal, Quebec, Canada
| | - Sara Birjandian
- Department of Biotechnology, McGill University, Montreal, Quebec, Canada
| | - Panteha Saberian
- Department of Biotechnology, McGill University, Montreal, Quebec, Canada
| | - Joseph G Hacia
- Department of Biochemistry and Molecular Medicine, Keck School of Medicine, Los Angeles, California
| | - Nancy E Braverman
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada.,Department of Pediatrics, Research Institute of the McGill University Health Center, Montreal, Quebec, Canada
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19
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Akşit A, van der Klei IJ. Yeast peroxisomes: How are they formed and how do they grow? Int J Biochem Cell Biol 2018; 105:24-34. [PMID: 30268746 DOI: 10.1016/j.biocel.2018.09.019] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 09/24/2018] [Accepted: 09/25/2018] [Indexed: 01/01/2023]
Abstract
Peroxisomes are single membrane enclosed cell organelles, which are present in almost all eukaryotic cells. In addition to the common peroxisomal pathways such as β-oxidation of fatty acids and decomposition of H2O2, these organelles fulfil a range of metabolic and non-metabolic functions. Peroxisomes are very important since various human disorders exist that are caused by a defect in peroxisome function. Here we describe our current knowledge on the molecular mechanisms of peroxisome biogenesis in yeast, including peroxisomal protein sorting, organelle dynamics and peroxisomal membrane contact sites.
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Affiliation(s)
- Arman Akşit
- Molecular Cell Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, the Netherlands
| | - Ida J van der Klei
- Molecular Cell Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, the Netherlands.
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20
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Abstract
Peroxisomes are ubiquitous and highly dynamic organelles that play a central role in the metabolism of lipids and reactive oxygen species. The importance of peroxisomal metabolism is illustrated by severe peroxisome biogenesis disorders in which functional peroxisomes are absent or disorders caused by single peroxisomal enzyme deficiencies. These multisystemic diseases manifest specific clinical and biochemical disturbances that originate from the affected peroxisomal pathways. An emerging role of the peroxisome has been identified in many types of diseases, including cancer, neurodegenerative disorders, aging, obesity, and diabetes. Peroxisome homeostasis is achieved via a tightly regulated interplay between peroxisome biogenesis and degradation via selective autophagy, which is commonly known as "pexophagy". Dysregulation of either peroxisome biogenesis or pexophagy may be detrimental to the health of cells and contribute to the pathophysiology of these diseases. Autophagy is an evolutionary conserved catabolic process for non-selective degradation of macromolecules and organelles in response to various stressors. In selective autophagy, specific cargo-recognizing receptors connect the cargo to the core autophagic machinery, and additional posttranslational modifications such as ubiquitination and phosphorylation regulate this process. Several stress conditions have been shown to stimulate pexophagy and decrease peroxisome abundance. However, our understanding of the mechanisms that particularly regulate mammalian pexophagy has been limited. In recent years considerable progress has been made uncovering signaling pathways, autophagy receptors and adaptors as well as posttranslational modifications involved in pexophagy. In this review, which is published back-to-back with a peroxisome review by Islinger et al. [(Histochem Cell Biol 137:547-574, 2018). The peroxisome: an update on mysteries 2.0], we focus on recent novel findings on the underlying molecular mechanisms of pexophagy in yeast and mammalian cells and highlight concerns and gaps in our knowledge.
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21
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Schwerter D, Grimm I, Girzalsky W, Erdmann R. Receptor recognition by the peroxisomal AAA complex depends on the presence of the ubiquitin moiety and is mediated by Pex1p. J Biol Chem 2018; 293:15458-15470. [PMID: 30097517 DOI: 10.1074/jbc.ra118.003936] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 07/23/2018] [Indexed: 01/14/2023] Open
Abstract
The receptor cycle of type I peroxisomal matrix protein import is completed by ubiquitination of the membrane-bound peroxisome biogenesis factor 5 (Pex5p) and its subsequent export back to the cytosol. The receptor export is the only ATP-dependent step of the whole process and is facilitated by two members of the AAA family of proteins (ATPases associated with various cellular activities), namely Pex1p and Pex6p. To gain further insight into substrate recognition by the AAA complex, we generated an N-terminally linked ubiquitin-Pex5p fusion protein. This fusion protein displayed biological activity because it is able to functionally complement a PEX5-deletion in Saccharomyces cerevisiae. In vitro assays revealed its interaction at WT level with the native cargo protein Pcs60p and Pex14p, a constituent of the receptor docking complex. We also demonstrate in vitro deubiquitination by the deubiquitinating enzyme Ubp15p. In vitro pulldown assays and cross-linking studies demonstrate that Pex5p recognition by the AAA complex depends on the presence of the ubiquitin moiety and is mediated by Pex1p.
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Affiliation(s)
- Daniel Schwerter
- From the Institute of Biochemistry and Pathobiochemistry, Faculty of Medicine, Systems Biochemistry, Ruhr-University Bochum, D-44780 Bochum, Germany
| | - Immanuel Grimm
- From the Institute of Biochemistry and Pathobiochemistry, Faculty of Medicine, Systems Biochemistry, Ruhr-University Bochum, D-44780 Bochum, Germany
| | - Wolfgang Girzalsky
- From the Institute of Biochemistry and Pathobiochemistry, Faculty of Medicine, Systems Biochemistry, Ruhr-University Bochum, D-44780 Bochum, Germany
| | - Ralf Erdmann
- From the Institute of Biochemistry and Pathobiochemistry, Faculty of Medicine, Systems Biochemistry, Ruhr-University Bochum, D-44780 Bochum, Germany
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22
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Rodrigues TA, Francisco T, Azevedo JE. PEX13 Enters the RING, Lives Fast, Dies Young. J Mol Biol 2018; 430:1559-1561. [PMID: 29655985 DOI: 10.1016/j.jmb.2018.04.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- Tony A Rodrigues
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal; Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal; Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Tânia Francisco
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal; Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal
| | - Jorge E Azevedo
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal; Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal; Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
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23
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Chen X, Devarajan S, Danda N, Williams C. Insights into the Role of the Peroxisomal Ubiquitination Machinery in Pex13p Degradation in the Yeast Hansenula polymorpha. J Mol Biol 2018; 430:1545-1558. [PMID: 29694833 DOI: 10.1016/j.jmb.2018.03.033] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 03/15/2018] [Accepted: 03/16/2018] [Indexed: 12/13/2022]
Abstract
The import of matrix proteins into peroxisomes in yeast requires the action of the ubiquitin-conjugating enzyme Pex4p and a complex consisting of the ubiquitin E3 ligases Pex2p, Pex10p and Pex12p. Together, this peroxisomal ubiquitination machinery is thought to ubiquitinate the cycling receptor protein Pex5p and members of the Pex20p family of co-receptors, a modification that is required for receptor recycling. However, recent reports have demonstrated that this machinery plays a role in additional peroxisome-associated processes. Hence, our understanding of the function of these proteins in peroxisome biology is still incomplete. Here, we identify a role for the peroxisomal ubiquitination machinery in the degradation of the peroxisomal membrane protein Pex13p. Our data demonstrate that Pex13p levels build up in cells lacking members of this machinery and also establish that Pex13p undergoes rapid degradation in wild-type cells. Furthermore, we show that Pex13p is ubiquitinated in wild-type cells and also establish that Pex13p ubiquitination is reduced in cells lacking a functional peroxisomal E3 ligase complex. Finally, deletion of PEX2 causes Pex13p to build up at the peroxisomal membrane. Taken together, our data provide further evidence that the role of the peroxisomal ubiquitination machinery in peroxisome biology goes much deeper than receptor recycling alone.
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Affiliation(s)
- Xin Chen
- Molecular Cell Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747AG Groningen, the Netherlands
| | - Srishti Devarajan
- Molecular Cell Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747AG Groningen, the Netherlands
| | - Natasha Danda
- Molecular Cell Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747AG Groningen, the Netherlands
| | - Chris Williams
- Molecular Cell Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747AG Groningen, the Netherlands.
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Suaste-Olmos F, Zirión-Martínez C, Takano-Rojas H, Peraza-Reyes L. Meiotic development initiation in the fungus Podospora anserina requires the peroxisome receptor export machinery. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1865:572-586. [DOI: 10.1016/j.bbamcr.2018.01.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 12/29/2017] [Accepted: 01/03/2018] [Indexed: 01/19/2023]
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25
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Law KB, Bronte-Tinkew D, Di Pietro E, Snowden A, Jones RO, Moser A, Brumell JH, Braverman N, Kim PK. The peroxisomal AAA ATPase complex prevents pexophagy and development of peroxisome biogenesis disorders. Autophagy 2018; 13:868-884. [PMID: 28521612 PMCID: PMC5446072 DOI: 10.1080/15548627.2017.1291470] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Peroxisome biogenesis disorders (PBDs) are metabolic disorders caused by the loss of peroxisomes. The majority of PBDs result from mutation in one of 3 genes that encode for the peroxisomal AAA ATPase complex (AAA-complex) required for cycling PEX5 for peroxisomal matrix protein import. Mutations in these genes are thought to result in a defect in peroxisome assembly by preventing the import of matrix proteins. However, we show here that loss of the AAA-complex does not prevent matrix protein import, but instead causes an upregulation of peroxisome degradation by macroautophagy, or pexophagy. The loss of AAA-complex function in cells results in the accumulation of ubiquitinated PEX5 on the peroxisomal membrane that signals pexophagy. Inhibiting autophagy by genetic or pharmacological approaches rescues peroxisome number, protein import and function. Our findings suggest that the peroxisomal AAA-complex is required for peroxisome quality control, whereas its absence results in the selective degradation of the peroxisome. Thus the loss of peroxisomes in PBD patients with mutations in their peroxisomal AAA-complex is a result of increased pexophagy. Our study also provides a framework for the development of novel therapeutic treatments for PBDs.
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Affiliation(s)
- Kelsey B Law
- a Cell Biology Program , Hospital for Sick Children, Peter Gilgan Centre for Research and Learning , Toronto , ON , Canada.,b Department of Biochemistry , University of Toronto , Toronto , ON , Canada
| | - Dana Bronte-Tinkew
- a Cell Biology Program , Hospital for Sick Children, Peter Gilgan Centre for Research and Learning , Toronto , ON , Canada
| | - Erminia Di Pietro
- c Research Institute of the MUHC and McGill University , Montreal , QC , Canada
| | - Ann Snowden
- d Kennedy Krieger Institute , Baltimore , MD , USA
| | | | - Ann Moser
- d Kennedy Krieger Institute , Baltimore , MD , USA
| | - John H Brumell
- a Cell Biology Program , Hospital for Sick Children, Peter Gilgan Centre for Research and Learning , Toronto , ON , Canada.,e Department of Molecular Genetics , University of Toronto , Toronto , ON , Canada.,f Institute of Medical Science, University of Toronto , Toronto , ON , Canada.,g SickKids IBD Centre , Hospital for Sick Children , Toronto , ON , Canada
| | - Nancy Braverman
- c Research Institute of the MUHC and McGill University , Montreal , QC , Canada
| | - Peter K Kim
- a Cell Biology Program , Hospital for Sick Children, Peter Gilgan Centre for Research and Learning , Toronto , ON , Canada.,b Department of Biochemistry , University of Toronto , Toronto , ON , Canada
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A pex1 missense mutation improves peroxisome function in a subset of Arabidopsis pex6 mutants without restoring PEX5 recycling. Proc Natl Acad Sci U S A 2018; 115:E3163-E3172. [PMID: 29555730 DOI: 10.1073/pnas.1721279115] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
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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27
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Kalel VC, Erdmann R. Unraveling of the Structure and Function of Peroxisomal Protein Import Machineries. Subcell Biochem 2018; 89:299-321. [PMID: 30378029 DOI: 10.1007/978-981-13-2233-4_13] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Peroxisomes are dynamic organelles of eukaryotic cells performing a wide range of functions including fatty acid oxidation, peroxide detoxification and ether-lipid synthesis in mammals. Peroxisomes lack their own DNA and therefore have to import proteins post-translationally. Peroxisomes can import folded, co-factor bound and even oligomeric proteins. The involvement of cycling receptors is a special feature of peroxisomal protein import. Complex machineries of peroxin (PEX) proteins mediate peroxisomal matrix and membrane protein import. Identification of PEX genes was dominated by forward genetic techniques in the early 90s. However, recent developments in proteomic techniques has revolutionized the detailed characterization of peroxisomal protein import. Here, we summarize the current knowledge on peroxisomal protein import with emphasis on the contribution of proteomic approaches to our understanding of the composition and function of the peroxisomal protein import machineries.
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Affiliation(s)
- Vishal C Kalel
- Department of Systems Biochemistry, Faculty of Medicine, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, Universitätsstr. 150, 44801, Bochum, Germany.
| | - Ralf Erdmann
- Department of Systems Biochemistry, Faculty of Medicine, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, Universitätsstr. 150, 44801, Bochum, Germany
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28
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Gonzalez KL, Fleming WA, Kao YT, Wright ZJ, Venkova SV, Ventura MJ, Bartel B. Disparate peroxisome-related defects in Arabidopsis pex6 and pex26 mutants link peroxisomal retrotranslocation and oil body utilization. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 92:110-128. [PMID: 28742939 PMCID: PMC5605450 DOI: 10.1111/tpj.13641] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 06/22/2017] [Accepted: 07/18/2017] [Indexed: 05/29/2023]
Abstract
Catabolism of fatty acids stored in oil bodies is essential for seed germination and seedling development in Arabidopsis. This fatty acid breakdown occurs in peroxisomes, organelles that sequester oxidative reactions. Import of peroxisomal enzymes is facilitated by peroxins including PEX5, a receptor that delivers cargo proteins from the cytosol to the peroxisomal matrix. After cargo delivery, a complex of the PEX1 and PEX6 ATPases and the PEX26 tail-anchored membrane protein removes ubiquitinated PEX5 from the peroxisomal membrane. We identified Arabidopsis pex6 and pex26 mutants by screening for inefficient seedling β-oxidation phenotypes. The mutants displayed distinct defects in growth, response to a peroxisomally metabolized auxin precursor, and peroxisomal protein import. The low PEX5 levels in these mutants were increased by treatment with a proteasome inhibitor or by combining pex26 with peroxisome-associated ubiquitination machinery mutants, suggesting that ubiquitinated PEX5 is degraded by the proteasome when the function of PEX6 or PEX26 is reduced. Combining pex26 with mutations that increase PEX5 levels either worsened or improved pex26 physiological and molecular defects, depending on the introduced lesion. Moreover, elevating PEX5 levels via a 35S:PEX5 transgene exacerbated pex26 defects and ameliorated the defects of only a subset of pex6 alleles, implying that decreased PEX5 is not the sole molecular deficiency in these mutants. We found peroxisomes clustered around persisting oil bodies in pex6 and pex26 seedlings, suggesting a role for peroxisomal retrotranslocation machinery in oil body utilization. The disparate phenotypes of these pex alleles may reflect unanticipated functions of the peroxisomal ATPase complex.
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Affiliation(s)
| | | | | | | | | | | | - Bonnie Bartel
- Corresponding author: Bonnie Bartel, Department of Biosciences, MS-140, Rice University, 6100 Main St., Houston TX, USA. Phone: 713-348-5602, Fax: 713-348-5154;
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29
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Wang W, Subramani S. Role of PEX5 ubiquitination in maintaining peroxisome dynamics and homeostasis. Cell Cycle 2017; 16:2037-2045. [PMID: 28933989 PMCID: PMC5731411 DOI: 10.1080/15384101.2017.1376149] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 08/24/2017] [Accepted: 09/01/2017] [Indexed: 12/15/2022] Open
Abstract
Peroxisomes are essential and dynamic organelles that allow cells to rapidly adapt and cope with changing environments and/or physiological conditions by modulation of both peroxisome biogenesis and turnover. Peroxisome biogenesis involves the assembly of peroxisome membranes and the import of peroxisomal matrix proteins. The latter depends on the receptor, PEX5, which recognizes peroxisomal matrix proteins in the cytosol directly or indirectly, and transports them to the peroxisomal lumen. In this review, we discuss the role of PEX5 ubiquitination in both peroxisome biogenesis and turnover, specifically in PEX5 receptor recycling, stability and abundance, as well as its role in pexophagy (autophagic degradation of peroxisomes).
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Affiliation(s)
- Wei Wang
- Section of Molecular Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Suresh Subramani
- Section of Molecular Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA, USA
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30
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Schwerter DP, Grimm I, Platta HW, Erdmann R. ATP-driven processes of peroxisomal matrix protein import. Biol Chem 2017; 398:607-624. [PMID: 27977397 DOI: 10.1515/hsz-2016-0293] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 12/11/2016] [Indexed: 12/13/2022]
Abstract
In peroxisomal matrix protein import two processes directly depend on the binding and hydrolysis of ATP, both taking place at the late steps of the peroxisomal import cycle. First, ATP hydrolysis is required to initiate a ubiquitin-transfer cascade to modify the import (co-)receptors. These receptors display a dual localization in the cytosol and at the peroxisomal membrane, whereas only the membrane bound fraction receives the ubiquitin modification. The second ATP-dependent process of the import cycle is carried out by the two AAA+-proteins Pex1p and Pex6p. These ATPases form a heterohexameric complex, which is recruited to the peroxisomal import machinery by the membrane anchor protein Pex15p. The Pex1p/Pex6p complex recognizes the ubiquitinated import receptors, pulls them out of the membrane and releases them into the cytosol. There the deubiquitinated receptors are provided for further rounds of import. ATP binding and hydrolysis are required for Pex1p/Pex6p complex formation and receptor export. In this review, we summarize the current knowledge on the peroxisomal import cascade. In particular, we will focus on the ATP-dependent processes, which are so far best understood in the model organism Saccharomyces cerevisiae.
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Affiliation(s)
- Daniel P Schwerter
- Abteilung für Systembiochemie, Institut für Biochemie und Pathobiochemie, Medizinische Fakultät der Ruhr-Universität Bochum, Universitätsstr. 150, D-44780 Bochum
| | - Immanuel Grimm
- Abteilung für Systembiochemie, Institut für Biochemie und Pathobiochemie, Medizinische Fakultät der Ruhr-Universität Bochum, Universitätsstr. 150, D-44780 Bochum
| | - Harald W Platta
- Biochemie Intrazellulärer Transportprozesse, Medizinische Fakultät der Ruhr-Universität Bochum, D-44780 Bochum
| | - Ralf Erdmann
- Abteilung für Systembiochemie, Institut für Biochemie und Pathobiochemie, Medizinische Fakultät der Ruhr-Universität Bochum, Universitätsstr. 150, D-44780 Bochum
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31
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Wang W, Xia ZJ, Farré JC, Subramani S. TRIM37, a novel E3 ligase for PEX5-mediated peroxisomal matrix protein import. J Cell Biol 2017; 216:2843-2858. [PMID: 28724525 PMCID: PMC5584156 DOI: 10.1083/jcb.201611170] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 04/14/2017] [Accepted: 06/13/2017] [Indexed: 12/22/2022] Open
Abstract
Most proteins destined for the peroxisomal matrix depend on the peroxisomal targeting signals (PTSs), which require the PTS receptor PEX5, whose deficiency causes fatal human peroxisomal biogenesis disorders (PBDs). TRIM37 gene mutations cause muscle-liver-brain-eye (mulibrey) nanism. We found that TRIM37 localizes in peroxisomal membranes and ubiquitylates PEX5 at K464 by interacting with its C-terminal 51 amino acids (CT51), which is required for PTS protein import. PEX5 mutations (K464A or ΔCT51), or TRIM37 depletion or mutation, reduce PEX5 abundance by promoting its proteasomal degradation, thereby impairing its functions in cargo binding and PTS protein import in human cells. TRIM37 or PEX5 depletion induces apoptosis and enhances sensitivity to oxidative stress, underscoring the cellular requirement for functional peroxisomes. Therefore, TRIM37-mediated ubiquitylation stabilizes PEX5 and promotes peroxisomal matrix protein import, suggesting that mulibrey nanism is a new PBD.
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Affiliation(s)
- Wei Wang
- Section of Molecular Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA
| | - Zhi-Jie Xia
- Section of Molecular Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA
| | - Jean-Claude Farré
- Section of Molecular Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA
| | - Suresh Subramani
- Section of Molecular Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA
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32
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Affiliation(s)
| | - Maria Daniela D'Agostino
- McGill University Department of Human Genetics and McGill University Health Center, Department of Medical Genetics, Montreal, QC, Canada
| | - Nancy Braverman
- McGill University Department of Human Genetics and Pediatrics, and The Research Institute of the McGill University Health Centre, Montreal, QC, Canada
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33
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Chan A, Schummer A, Fischer S, Schröter T, Cruz-Zaragoza LD, Bender J, Drepper F, Oeljeklaus S, Kunau WH, Girzalsky W, Warscheid B, Erdmann R. Pex17p-dependent assembly of Pex14p/Dyn2p-subcomplexes of the peroxisomal protein import machinery. Eur J Cell Biol 2016; 95:585-597. [PMID: 27823812 DOI: 10.1016/j.ejcb.2016.10.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 09/30/2016] [Accepted: 10/10/2016] [Indexed: 01/10/2023] Open
Abstract
Peroxisomal matrix protein import is facilitated by cycling receptors that recognize their cargo proteins in the cytosol by peroxisomal targeting sequences (PTS). In the following, the assembled receptor-cargo complex is targeted to the peroxisomal membrane where it docks to the docking-complex as part of the peroxisomal translocation machinery. The docking-complex is composed of Pex13p, Pex14p and in yeast also Pex17p, whose function is still elusive. In order to characterize the function of Pex17p, we compared the composition and size of peroxisomal receptor-docking complexes from wild-type and pex17Δ cells. Our data demonstrate that the deficiency of Pex17p affects the stoichiometry of the constituents of an isolated 600kDa complex and that pex17Δ cells lack a high molecular weight complex (>900kDa) of unknown function. We identified the dynein light chain protein Dyn2p as an additional core component of the Pex14p/Pex17p-complex. Both, Pex14p and Pex17p interact directly with Dyn2p, but in vivo, Pex17p turned out to be prerequisite for an association of Dyn2p with Pex14p. Finally, like pex17Δ also dyn2Δ cells lack the high molecular weight complex. As dyn2Δ cells also display reduced peroxisomal function, our data indicate that Dyn2p-dependent formation of the high molecular weight Pex14p-complex is required to maintain peroxisomal function on wild-type level.
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Affiliation(s)
- Anna Chan
- Institute of Biochemistry and Pathobiochemistry, Faculty of Medicine, System Biochemistry, Ruhr-University Bochum, Bochum, Germany
| | - Andreas Schummer
- Department of Biochemistry and Functional Proteomics, Faculty of Biology and BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Sven Fischer
- Department of Biochemistry and Functional Proteomics, Faculty of Biology and BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Thomas Schröter
- Institute of Biochemistry and Pathobiochemistry, Faculty of Medicine, System Biochemistry, Ruhr-University Bochum, Bochum, Germany
| | - Luis Daniel Cruz-Zaragoza
- Institute of Biochemistry and Pathobiochemistry, Faculty of Medicine, System Biochemistry, Ruhr-University Bochum, Bochum, Germany
| | - Julian Bender
- Department of Biochemistry and Functional Proteomics, Faculty of Biology and BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Friedel Drepper
- Department of Biochemistry and Functional Proteomics, Faculty of Biology and BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Silke Oeljeklaus
- Department of Biochemistry and Functional Proteomics, Faculty of Biology and BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Wolf-H Kunau
- Institute of Biochemistry and Pathobiochemistry, Faculty of Medicine, System Biochemistry, Ruhr-University Bochum, Bochum, Germany
| | - Wolfgang Girzalsky
- Institute of Biochemistry and Pathobiochemistry, Faculty of Medicine, System Biochemistry, Ruhr-University Bochum, Bochum, Germany
| | - Bettina Warscheid
- Department of Biochemistry and Functional Proteomics, Faculty of Biology and BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
| | - Ralf Erdmann
- Institute of Biochemistry and Pathobiochemistry, Faculty of Medicine, System Biochemistry, Ruhr-University Bochum, Bochum, Germany.
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34
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Peroxisomal protein import pores. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:821-7. [DOI: 10.1016/j.bbamcr.2015.10.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 10/14/2015] [Accepted: 10/16/2015] [Indexed: 02/06/2023]
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35
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Motley AM, Galvin PC, Ekal L, Nuttall JM, Hettema EH. Reevaluation of the role of Pex1 and dynamin-related proteins in peroxisome membrane biogenesis. J Cell Biol 2016; 211:1041-56. [PMID: 26644516 PMCID: PMC4674274 DOI: 10.1083/jcb.201412066] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Analysis of Pex1 and dynamin-related protein function indicates peroxisomes multiply mainly by growth and division in Saccharomyces cerevisiae, whereas no evidence was found for the previously proposed role for Pex1 in peroxisome formation by fusion of ER-derived preperoxisomal vesicles. 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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Affiliation(s)
- Alison M Motley
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, England, UK
| | - Paul C Galvin
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, England, UK
| | - Lakhan Ekal
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, England, UK
| | - James M Nuttall
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, England, UK
| | - Ewald H Hettema
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, England, UK
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36
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Bhogal MS, Lanyon-Hogg T, Johnston KA, Warriner SL, Baker A. Covalent Label Transfer between Peroxisomal Importomer Components Reveals Export-driven Import Interactions. J Biol Chem 2015; 291:2460-8. [PMID: 26567336 PMCID: PMC4732227 DOI: 10.1074/jbc.m115.686501] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Indexed: 11/06/2022] Open
Abstract
Peroxisomes are vital metabolic organelles found in almost all eukaryotic organisms, and they rely exclusively on import of their matrix protein content from the cytosol. In vitro import of proteins into isolated peroxisomal fractions has provided a wealth of knowledge on the import process. However, the common method of protease protection garnered no information on the import of an N-terminally truncated PEX5 (PEX5C) receptor construct or peroxisomal malate dehydrogenase 1 (pMDH1) cargo protein into sunflower peroxisomes because of high degrees of protease susceptibility or resistance, respectively. Here we present a means for analysis of in vitro import through a covalent biotin label transfer and employ this method to the import of PEX5C. Label transfer demonstrates that the PEX5C construct is monomeric under the conditions of the import assay. This technique was capable of identifying the PEX5-PEX14 interaction as the first interaction of the import process through competition experiments. Labeling of the peroxisomal protein import machinery by PEX5C demonstrated that this interaction was independent of added cargo protein, and, strikingly, the interaction between PEX5C and the import machinery was shown to be ATP-dependent. These important mechanistic insights highlight the power of label transfer in studying interactions, rather than proteins, of interest and demonstrate that this technique should be applied to future studies of peroxisomal in vitro import.
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Affiliation(s)
- Moninder S Bhogal
- From the Centre for Plant Sciences and School of Molecular and Cellular Biology and
| | - Thomas Lanyon-Hogg
- From the Centre for Plant Sciences and School of Molecular and Cellular Biology and School of Chemistry and Astbury Centre, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Katherine A Johnston
- From the Centre for Plant Sciences and School of Molecular and Cellular Biology and
| | - Stuart L Warriner
- School of Chemistry and Astbury Centre, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Alison Baker
- From the Centre for Plant Sciences and School of Molecular and Cellular Biology and
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37
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Grimm I, Erdmann R, Girzalsky W. Role of AAA(+)-proteins in peroxisome biogenesis and function. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1863:828-37. [PMID: 26453804 DOI: 10.1016/j.bbamcr.2015.10.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 09/30/2015] [Accepted: 10/03/2015] [Indexed: 11/16/2022]
Abstract
Mutations in the PEX1 gene, which encodes a protein required for peroxisome biogenesis, are the most common cause of the Zellweger spectrum diseases. The recognition that Pex1p shares a conserved ATP-binding domain with p97 and NSF led to the discovery of the extended family of AAA+-type ATPases. So far, four AAA+-type ATPases are related to peroxisome function. Pex6p functions together with Pex1p in peroxisome biogenesis, ATAD1/Msp1p plays a role in membrane protein targeting and a member of the Lon-family of proteases is associated with peroxisomal quality control. This review summarizes the current knowledge on the AAA+-proteins involved in peroxisome biogenesis and function.
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Affiliation(s)
- Immanuel Grimm
- Abteilung für Systembiochemie, Medizinische Fakultät der Ruhr-Universität Bochum, D-44780 Bochum, Germany
| | - Ralf Erdmann
- Abteilung für Systembiochemie, Medizinische Fakultät der Ruhr-Universität Bochum, D-44780 Bochum, Germany.
| | - Wolfgang Girzalsky
- Abteilung für Systembiochemie, Medizinische Fakultät der Ruhr-Universität Bochum, D-44780 Bochum, Germany.
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38
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The Design and Structure of Outer Membrane Receptors from Peroxisomes, Mitochondria, and Chloroplasts. Structure 2015; 23:1783-1800. [DOI: 10.1016/j.str.2015.08.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 07/20/2015] [Accepted: 08/10/2015] [Indexed: 01/03/2023]
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Platta HW, Brinkmeier R, Reidick C, Galiani S, Clausen MP, Eggeling C. Regulation of peroxisomal matrix protein import by ubiquitination. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1863:838-49. [PMID: 26367801 DOI: 10.1016/j.bbamcr.2015.09.010] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 09/09/2015] [Accepted: 09/10/2015] [Indexed: 02/02/2023]
Abstract
Peroxisomes are organelles that play an important role in many cellular tasks. The functionality of peroxisomes depends on the proper import of their matrix proteins. Peroxisomal matrix proteins are imported posttranslationally in a folded, sometimes even oligomeric state. They harbor a peroxisomal targeting sequence (PTS), which is recognized by dynamic PTS-receptors in the cytosol. The PTS-receptors ferry the cargo to the peroxisomal membrane, where they become part of a transient import pore and then release the cargo into the peroxisomal lumen. Subsequentially, the PTS-receptors are ubiquitinated in order to mark them for the export-machinery, which releases them back to the cytosol. Upon deubiquitination, the PTS-receptors can facilitate further rounds of cargo import. Because the ubiquitination of the receptors is an essential step in the import cycle, it also represents a central regulatory element that governs peroxisomal dynamics. In this review we want to give an introduction to the functional role played by ubiquitination during peroxisomal protein import and highlight the mechanistic concepts that have emerged based on data derived from different species since the discovery of the first ubiquitinated peroxin 15years ago. Moreover, we discuss future tasks and the potential of using advanced technologies for investigating further details of peroxisomal protein transport.
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Affiliation(s)
- Harald W Platta
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, 44780 Bochum, Germany.
| | - Rebecca Brinkmeier
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Christina Reidick
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Silvia Galiani
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Headley Way, Oxford OX3 9DS, United Kingdom
| | - Mathias P Clausen
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Headley Way, Oxford OX3 9DS, United Kingdom
| | - Christian Eggeling
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Headley Way, Oxford OX3 9DS, United Kingdom.
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40
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Cysteine-specific ubiquitination protects the peroxisomal import receptor Pex5p against proteasomal degradation. Biosci Rep 2015; 35:BSR20150103. [PMID: 26182377 PMCID: PMC4613714 DOI: 10.1042/bsr20150103] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 05/01/2015] [Indexed: 11/22/2022] Open
Abstract
Peroxisomal import receptors cycle between the peroxisomal membrane and the cytosol. A monoubiquitinated cysteine is required for efficient recycling of the peroxisomal import receptor Pex5p and prevents the protein from polyubiquitination, which leads to a rapid degradation of the protein. Peroxisomal matrix protein import is mediated by dynamic import receptors, which cycle between the peroxisomal membrane and the cytosol. Proteins with a type 1 peroxisomal targeting signal (PTS1) are bound by the import receptor Pex5p in the cytosol and guided to the peroxisomal membrane. After cargo translocation into the peroxisomal matrix, the receptor is released from the membrane back to the cytosol in an ATP-dependent manner by the AAA-type ATPases Pex1p and Pex6p. These mechanoenzymes recognize ubiquitinated Pex5p-species as substrates for membrane extraction. The PTS1-receptor is either polyubiquitinated via peptide bonds at two certain lysines and results in proteasomal degradation or monoubiquitinated via a thioester-bond at a conserved cysteine, which enables the recycling of Pex5p and further rounds of matrix protein import. To investigate the physiological relevance of the conserved N-terminal cysteine of Pex5p, the known target amino acids for ubiquitination were substituted by site-directed mutagenesis. In contrast with Pex5pC6A, Pex5pC6K turned out to be functional in PTS1 import and utilization of oleic acid, independent of the lysines at position 18 and 24. In contrast with wild-type Pex5p, Pex5pC6K displays an ubiquitination pattern, similar to the polyubiquitination pattern of Pex4p or Pex22p mutant strains. Moreover, Pex5pC6K displays a significantly reduced steady-state level when the deubiquitinating enzyme Ubp15p is missing. Thus, our results indicate that not the cysteine residue but the position of ubiquitination is important for Pex5p function. The presence of the cysteine prevents polyubiquitination and rapid degradation of Pex5p.
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41
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Sugimoto Y, Vigilante A, Darbo E, Zirra A, Militti C, D’Ambrogio A, Luscombe NM, Ule J. hiCLIP reveals the in vivo atlas of mRNA secondary structures recognized by Staufen 1. Nature 2015; 519:491-4. [PMID: 25799984 PMCID: PMC4376666 DOI: 10.1038/nature14280] [Citation(s) in RCA: 214] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2014] [Accepted: 02/02/2015] [Indexed: 02/02/2023]
Abstract
The structure of messenger RNA is important for post-transcriptional regulation, mainly because it affects binding of trans-acting factors. However, little is known about the in vivo structure of full-length mRNAs. Here we present hiCLIP, a biochemical technique for transcriptome-wide identification of RNA secondary structures interacting with RNA-binding proteins (RBPs). Using this technique to investigate RNA structures bound by Staufen 1 (STAU1) in human cells, we uncover a dominance of intra-molecular RNA duplexes, a depletion of duplexes from coding regions of highly translated mRNAs, an unexpected prevalence of long-range duplexes in 3' untranslated regions (UTRs), and a decreased incidence of single nucleotide polymorphisms in duplex-forming regions. We also discover a duplex spanning 858 nucleotides in the 3' UTR of the X-box binding protein 1 (XBP1) mRNA that regulates its cytoplasmic splicing and stability. Our study reveals the fundamental role of mRNA secondary structures in gene expression and introduces hiCLIP as a widely applicable method for discovering new, especially long-range, RNA duplexes.
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Affiliation(s)
- Yoichiro Sugimoto
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Alessandra Vigilante
- Cancer Research UK London Research Institute, 44 Lincoln’s Inn Fields, London WC2A 3LY, UK
- UCL Genetics Institute, Department of Genetics, Evolution & Environment, University College London, Gower Street, London WC1E 6BT, UK
| | - Elodie Darbo
- Cancer Research UK London Research Institute, 44 Lincoln’s Inn Fields, London WC2A 3LY, UK
| | - Alexandra Zirra
- Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Cristina Militti
- Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Andrea D’Ambrogio
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
- Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Nicholas M Luscombe
- Cancer Research UK London Research Institute, 44 Lincoln’s Inn Fields, London WC2A 3LY, UK
- UCL Genetics Institute, Department of Genetics, Evolution & Environment, University College London, Gower Street, London WC1E 6BT, UK
- Okinawa Institute of Science & Technology, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa 904-0495, Japan
| | - Jernej Ule
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
- Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
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42
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Gardner BM, Chowdhury S, Lander GC, Martin A. The Pex1/Pex6 complex is a heterohexameric AAA+ motor with alternating and highly coordinated subunits. J Mol Biol 2015; 427:1375-1388. [PMID: 25659908 DOI: 10.1016/j.jmb.2015.01.019] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2015] [Revised: 01/23/2015] [Accepted: 01/24/2015] [Indexed: 12/13/2022]
Abstract
Pex1 and Pex6 are Type-2 AAA+ ATPases required for the de novo biogenesis of peroxisomes. Mutations in Pex1 and Pex6 account for the majority of the most severe forms of peroxisome biogenesis disorders in humans. Here, we show that the ATP-dependent complex of Pex1 and Pex6 from Saccharomyces cerevisiae is a heterohexamer with alternating subunits. Within the Pex1/Pex6 complex, only the D2 ATPase ring hydrolyzes ATP, while nucleotide binding in the D1 ring promotes complex assembly. ATP hydrolysis by Pex1 is highly coordinated with that of Pex6. Furthermore, Pex15, the membrane anchor required for Pex1/Pex6 recruitment to peroxisomes, inhibits the ATP-hydrolysis activity of Pex1/Pex6.
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Affiliation(s)
- Brooke M Gardner
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3200, USA; Miller Institute for Basic Research in Science, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Saikat Chowdhury
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Gabriel C Lander
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Andreas Martin
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3200, USA; California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720-3220, USA.
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43
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Abstract
Pex7p is the cytosolic receptor for peroxisomal matrix proteins harbouring PTS2 (peroxisome-targeting signal type-2). Mutations in the PEX7 gene cause RCDP (rhizomelic chondrodysplasia punctata) type 1, a distinct PTS2-import-defective phenotype of peroxisome biogenesis disorders. The mechanisms by which the protein level and quality of Pex7p are controlled remain largely unknown. In the present study we show that dysfunctional Pex7p, including mutants from RCDP patients, is degraded by a ubiquitin-dependent proteasomal pathway involving the CRL4A (Cullin4A-RING ubiquitin ligase) complex. Furthermore, we demonstrate that the degradation of dysfunctional Pex7p is essential for maintaining normal PTS2 import, thereby suggesting that CRL4A functions as an E3 ligase in the quality control of Pex7p. Our results define a mechanism underlying Pex7p homoeostasis and highlight its importance for regulating PTS2 import. These findings may lead to a new approach to Pex7p-based therapies for the treatment of peroxisome biogenesis disorders such as RCDP.
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44
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El Magraoui F, Schrötter A, Brinkmeier R, Kunst L, Mastalski T, Müller T, Marcus K, Meyer HE, Girzalsky W, Erdmann R, Platta HW. The cytosolic domain of Pex22p stimulates the Pex4p-dependent ubiquitination of the PTS1-receptor. PLoS One 2014; 9:e105894. [PMID: 25162638 PMCID: PMC4146569 DOI: 10.1371/journal.pone.0105894] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Accepted: 07/25/2014] [Indexed: 01/08/2023] Open
Abstract
Peroxisomal biogenesis is an ubiquitin-dependent process because the receptors required for the import of peroxisomal matrix proteins are controlled via their ubiquitination status. A key step is the monoubiquitination of the import receptor Pex5p by the ubiquitin-conjugating enzyme (E2) Pex4p. This monoubiquitination is supposed to take place after Pex5p has released the cargo into the peroxisomal matrix and primes Pex5p for the extraction from the membrane by the mechano-enzymes Pex1p/Pex6p. These two AAA-type ATPases export Pex5p back to the cytosol for further rounds of matrix protein import. Recently, it has been reported that the soluble Pex4p requires the interaction to its peroxisomal membrane-anchor Pex22p to display full activity. Here we demonstrate that the soluble C-terminal domain of Pex22p harbours its biological activity and that this activity is independent from its function as membrane-anchor of Pex4p. We show that Pex4p can be functionally fused to the trans-membrane segment of the membrane protein Pex3p, which is not directly involved in Pex5p-ubiquitination and matrix protein import. However, this Pex3(N)-Pex4p chimera can only complement the double-deletion strain pex4Δ/pex22Δ and ensure optimal Pex5p-ubiquitination when the C-terminal part of Pex22p is additionally expressed in the cell. Thus, while the membrane-bound portion Pex22(N)p is not required when Pex4p is fused to Pex3(N)p, the soluble Pex22(C)p is essential for peroxisomal biogenesis and efficient monoubiquitination of the import receptor Pex5p by the E3-ligase Pex12p in vivo and in vitro. The results merge into a picture of an ubiquitin-conjugating complex at the peroxisomal membrane consisting of three domains: the ubiquitin-conjugating domain (Pex4p), a membrane-anchor domain (Pex22(N)p) and an enhancing domain (Pex22(C)p), with the membrane-anchor domain being mutually exchangeable, while the Ubc- and enhancer-domains are essential.
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Affiliation(s)
- Fouzi El Magraoui
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, Bochum, Germany
- Systembiochemie, Ruhr-Universität Bochum, Bochum, Germany
- Biomedizinische Forschung, Leibniz-Institut für Analytische Wissenschaften - ISAS -e.V., Dortmund, Germany
| | - Andreas Schrötter
- Medizinische Proteomik/Bioanalytik, AG Neuro Proteomics, Medizinisches Proteom-Center, Bochum, Germany
- Biomedizinische Forschung, Leibniz-Institut für Analytische Wissenschaften - ISAS -e.V., Dortmund, Germany
| | - Rebecca Brinkmeier
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, Bochum, Germany
| | - Lena Kunst
- Systembiochemie, Ruhr-Universität Bochum, Bochum, Germany
| | - Thomas Mastalski
- Medizinische Proteomik/Bioanalytik, AG Neuro Proteomics, Medizinisches Proteom-Center, Bochum, Germany
| | - Thorsten Müller
- Funktionelle Proteomik, Medizinisches Proteom-Center, Bochum, Germany
| | - Katrin Marcus
- Funktionelle Proteomik, Medizinisches Proteom-Center, Bochum, Germany
| | - Helmut E. Meyer
- Biomedizinische Forschung, Leibniz-Institut für Analytische Wissenschaften - ISAS -e.V., Dortmund, Germany
| | | | - Ralf Erdmann
- Systembiochemie, Ruhr-Universität Bochum, Bochum, Germany
- * E-mail: (RE); (HWP)
| | - Harald W. Platta
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, Bochum, Germany
- * E-mail: (RE); (HWP)
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45
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Tamura S, Matsumoto N, Takeba R, Fujiki Y. AAA peroxins and their recruiter Pex26p modulate the interactions of peroxins involved in peroxisomal protein import. J Biol Chem 2014; 289:24336-46. [PMID: 25016021 DOI: 10.1074/jbc.m114.588038] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Pex1p and Pex6p are required for the relocation of the import receptor Pex5p from the peroxisomal membrane to the cytosol. We herein show that mammalian Pex26p directly binds to Pex14p, the initial docking receptor of Pex5p, and interacts with Pex5p via Pex14p. The binding affinity of Pex26p to Pex14p is altered by Pex5p. Further evidence suggests that the N-terminal region in Pex26p acts as a scaffold protein to recruit Pex14p·Pex5p complex together with Pex1p·Pex6p complexes on peroxisomes. Pex26p binding to Pex14p was suppressed by overexpression of Pex1p and Pex6p in an ATP-dependent manner, whereas Pex14p was not competed out by Pex1p and Pex6p from Pex26p mutant defective in peroxisomal matrix protein import. These results suggested that peroxisome biogenesis requires Pex1p- and Pex6p-regulated dissociation of Pex14p from Pex26p. Pex1p homo-oligomer directly binds to Pex5p as assessed by a surface plasmon resonance-based assay. Moreover, cytosolic Pex1p is likely to maintain the functional oligomer of Pex5p. Taken together, in the peroxisomal protein import, AAA peroxins modulate the interaction between Pex26p and Pex14p on peroxisome membrane as well as Pex5p oligomer in the cytosol.
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Affiliation(s)
- Shigehiko Tamura
- Faculty of Arts and Science, Kyushu University, Fukuoka 812-8581, Japan and Graduate School of Systems Life Sciences, Kyushu University Graduate School, Fukuoka 812-8581, Japan
| | - Naomi Matsumoto
- Graduate School of Systems Life Sciences, Kyushu University Graduate School, Fukuoka 812-8581, Japan
| | - Ryota Takeba
- Graduate School of Systems Life Sciences, Kyushu University Graduate School, Fukuoka 812-8581, Japan
| | - Yukio Fujiki
- From the Department of Biology, Faculty of Sciences, and
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46
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Williams C. Going against the flow: A case for peroxisomal protein export. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:1386-92. [DOI: 10.1016/j.bbamcr.2014.04.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 04/03/2014] [Accepted: 04/07/2014] [Indexed: 10/25/2022]
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47
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Lanyon-Hogg T, Hooper J, Gunn S, Warriner SL, Baker A. PEX14 binding to Arabidopsis PEX5 has differential effects on PTS1 and PTS2 cargo occupancy of the receptor. FEBS Lett 2014; 588:2223-9. [PMID: 24879895 PMCID: PMC4065332 DOI: 10.1016/j.febslet.2014.05.038] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 04/16/2014] [Accepted: 05/15/2014] [Indexed: 12/11/2022]
Abstract
The interaction between Arabidopsis PEX5 and PEX14N is independent of cargo binding. The affinity of a PTS1 peptide for PEX5 is unaffected by PEX14N binding. Arabidopsis PEX5 complexes PTS1 and PTS2 cargoes. PEX5 and 7 co-isolate with PEX14N, but the PTS2 cargo thiolase does not. PEX14N does not unload canonical PTS1 cargo peptide in vitro but may play a role in PTS2 release.
PEX5 acts as a cycling receptor for import of PTS1 proteins into peroxisomes and as a co-receptor for PEX7, the PTS2 receptor, but the mechanism of cargo unloading has remained obscure. Using recombinant protein domains we show PEX5 binding to the PEX14N-terminal domain (PEX14N) has no effect on the affinity of PEX5 for a PTS1 containing peptide. PEX5 can form a complex containing both recombinant PTS1 cargo and endogenous PEX7-thiolase simultaneously but isolation of the complex via the PEX14 construct resulted in an absence of thiolase, suggesting a possible role for PEX14 in the unloading of PTS2 cargos. pMDH1physically interacts with PEX5 by pull down (View interaction) PEX5Cbinds to PEX14N by filter binding (View interaction) PEX14Nbinds to PEX5C by pull down (View interaction) PEX14Nphysically interacts with PEX7 by pull down (View interaction) PEX5physically interacts with PEX7 by pull down (View interaction) DCI1physically interacts with PEX5 by pull down (View interaction) PEX5physically interacts with thiolase PTS2-cargo by pull down (View interaction) pMDH1physically interacts with PEX7 by pull down (View interaction) DCI1physically interacts with thiolase PTS2-cargo by pull down (View interaction) DCI1physically interacts with PEX7 by pull down (View interaction) PEX14Nphysically interacts with PEX5 by pull down (View interaction)
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Affiliation(s)
- Thomas Lanyon-Hogg
- Centre for Plant Sciences, Irene Manton Building, University of Leeds, Leeds LS2 9JT, UK; School of Chemistry, University of Leeds, Leeds LS2 9JT, UK
| | - Jacob Hooper
- School of Chemistry, University of Leeds, Leeds LS2 9JT, UK
| | - Sarah Gunn
- Centre for Plant Sciences, Irene Manton Building, University of Leeds, Leeds LS2 9JT, UK; School of Chemistry, University of Leeds, Leeds LS2 9JT, UK
| | | | - Alison Baker
- Centre for Plant Sciences, Irene Manton Building, University of Leeds, Leeds LS2 9JT, UK.
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48
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Okumoto K, Noda H, Fujiki Y. Distinct modes of ubiquitination of peroxisome-targeting signal type 1 (PTS1) receptor Pex5p regulate PTS1 protein import. J Biol Chem 2014; 289:14089-108. [PMID: 24662292 DOI: 10.1074/jbc.m113.527937] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Peroxisome targeting signal type-1 (PTS1) receptor, Pex5p, is a key player in peroxisomal matrix protein import. Pex5p recognizes PTS1 cargoes in the cytosol, targets peroxisomes, translocates across the membrane, unloads the cargoes, and shuttles back to the cytosol. Ubiquitination of Pex5p at a conserved cysteine is required for the exit from peroxisomes. However, any potential ubiquitin ligase (E3) remains unidentified in mammals. Here, we establish an in vitro ubiquitination assay system and demonstrate that RING finger Pex10p functions as an E3 with an E2, UbcH5C. The E3 activity of Pex10p is essential for its peroxisome-restoring activity, being enhanced by another RING peroxin, Pex12p. The Pex10p·Pex12p complex catalyzes monoubiquitination of Pex5p at one of multiple lysine residues in vitro, following the dissociation of Pex5p from Pex14p and the PTS1 cargo. Several lines of evidence with lysine-to-arginine mutants of Pex5p demonstrate that Pex10p RING E3-mediated ubiquitination of Pex5p is required for its efficient export from peroxisomes to the cytosol and peroxisomal matrix protein import. RING peroxins are required for both modes of Pex5p ubiquitination, thus playing a pivotal role in Pex5p shuttling.
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Affiliation(s)
- Kanji Okumoto
- From the Department of Biology, Faculty of Sciences, and the Graduate School of Systems Life Sciences, Kyushu University Graduate School, Fukuoka 812-8581, Japan
| | - Hiromi Noda
- From the Department of Biology, Faculty of Sciences, and
| | - Yukio Fujiki
- From the Department of Biology, Faculty of Sciences, and
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49
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Nuttall JM, Motley AM, Hettema EH. Deficiency of the exportomer components Pex1, Pex6, and Pex15 causes enhanced pexophagy in Saccharomyces cerevisiae. Autophagy 2014; 10:835-45. [PMID: 24657987 PMCID: PMC5119063 DOI: 10.4161/auto.28259] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Turnover of damaged, dysfunctional, or excess organelles is critical to cellular homeostasis. We screened mutants disturbed in peroxisomal protein import, and found that a deficiency in the exportomer subunits Pex1, Pex6, and Pex15 results in enhanced turnover of peroxisomal membrane structures compared with other mutants. Strikingly, almost all peroxisomal membranes were associated with phagophore assembly sites in pex1Δ atg1Δ cells. Degradation depended on Atg11 and the pexophagy receptor Atg36, which mediates degradation of superfluous peroxisomes. Mutants of PEX1, PEX6, and PEX15 accumulate ubiquitinated receptors at the peroxisomal membrane. This accumulation has been suggested to trigger pexophagy in mammalian cells. We show by genetic analysis that preventing this accumulation does not abolish pexophagy in Saccharomyces cerevisiae. We find Atg36 is modified in pex1Δ cells even when Atg11 binding is prevented, suggesting Atg36 modification is an early event in the degradation of dysfunctional peroxisomal structures in pex1Δ cells via pexophagy.
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Affiliation(s)
- James M Nuttall
- Department of Molecular Biology and Biotechnology; University of Sheffield, Western Bank; Sheffield, UK
| | - Alison M Motley
- Department of Molecular Biology and Biotechnology; University of Sheffield, Western Bank; Sheffield, UK
| | - Ewald H Hettema
- Department of Molecular Biology and Biotechnology; University of Sheffield, Western Bank; Sheffield, UK
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50
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Kabani M, Redeker V, Melki R. A role for the proteasome in the turnover of Sup35p and in [PSI(+) ] prion propagation. Mol Microbiol 2014; 92:507-28. [PMID: 24589377 DOI: 10.1111/mmi.12572] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/27/2014] [Indexed: 01/21/2023]
Abstract
Yeast prions are superb models for understanding the mechanisms of self-perpetuating protein aggregates formation. [PSI(+) ] stands among the most documented yeast prions and results from self-assembly of the translation termination factor Sup35p into protein fibrils. A plethora of cellular factors were shown to affect [PSI(+) ] formation and propagation. Clearance of Sup35p prion particles is however poorly understood and documented. Here, we investigated the role of the proteasome in the degradation of Sup35p and in [PSI(+) ] prion propagation. We found that cells lacking the RPN4 gene, which have reduced intracellular proteasome pools, accumulated Sup35p and have defects in [PSI(+) ] formation and propagation. Sup35p is degraded in vitro by the 26S and 20S proteasomes in a ubiquitin-independent manner, generating an array of amyloidogenic peptides derived from its prion-domain. We also demonstrate the formation of a proteasome-resistant fragment spanning residues 83-685 which is devoid of the prion-domain that is essential for [PSI(+) ] propagation. Most important was the finding that the 26S and 20S proteasomes degrade Sup35p fibrils in vitro and abolish their infectivity. Our results point to an overlooked role of the proteasome in clearing toxic protein aggregates, and have important implications for a better understanding of the life cycle of infectious protein assemblies.
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Affiliation(s)
- Mehdi Kabani
- Laboratoire d'Enzymologie et Biochimie Structurales, CNRS, Bât. 34, Avenue de la Terrasse, F-91190, Gif-sur-Yvette, France
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