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Mastalski T, Brinkmeier R, Platta HW. The Peroxisomal PTS1-Import Defect of PEX1- Deficient Cells Is Independent of Pexophagy in Saccharomyces cerevisiae. Int J Mol Sci 2020; 21:ijms21030867. [PMID: 32013259 PMCID: PMC7037794 DOI: 10.3390/ijms21030867] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 01/25/2020] [Accepted: 01/27/2020] [Indexed: 01/02/2023] Open
Abstract
The important physiologic role of peroxisomes is shown by the occurrence of peroxisomal biogenesis disorders (PBDs) in humans. This spectrum of autosomal recessive metabolic disorders is characterized by defective peroxisome assembly and impaired peroxisomal functions. PBDs are caused by mutations in the peroxisomal biogenesis factors, which are required for the correct compartmentalization of peroxisomal matrix enzymes. Recent work from patient cells that contain the Pex1(G843D) point mutant suggested that the inhibition of the lysosome, and therefore the block of pexophagy, was beneficial for peroxisomal function. The resulting working model proposed that Pex1 may not be essential for matrix protein import at all, but rather for the prevention of pexophagy. Thus, the observed matrix protein import defect would not be caused by a lack of Pex1 activity, but rather by enhanced removal of peroxisomal membranes via pexophagy. In the present study, we can show that the specific block of PEX1 deletion-induced pexophagy does not restore peroxisomal matrix protein import or the peroxisomal function in beta-oxidation in yeast. Therefore, we conclude that Pex1 is directly and essentially involved in peroxisomal matrix protein import, and that the PEX1 deletion-induced pexophagy is not responsible for the defect in peroxisomal function. In order to point out the conserved mechanism, we discuss our findings in the context of the working models of peroxisomal biogenesis and pexophagy in yeasts and mammals.
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Boutouja F, Stiehm CM, Mastalski T, Brinkmeier R, Reidick C, El Magraoui F, Platta HW. Vps10-mediated targeting of Pep4 determines the activity of the vacuole in a substrate-dependent manner. Sci Rep 2019; 9:10557. [PMID: 31332264 PMCID: PMC6646403 DOI: 10.1038/s41598-019-47184-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 07/12/2019] [Indexed: 12/21/2022] Open
Abstract
The vacuole is the hydrolytic compartment of yeast cells and has a similar function as the lysosome of higher eukaryotes in detoxification and recycling of macromolecules. We analysed the contribution of single vacuolar enzymes to pexophagy and identified the phospholipase Atg15, the V-ATPase factor Vma2 and the serine-protease Prb1 along with the already known aspartyl-protease Pep4 (Proteinase A) to be required for this pathway. We also analysed the trafficking receptor Vps10, which is required for an efficient vacuolar targeting of the precursor form of Pep4. Here we demonstrate a novel context-dependent role of Vps10 in autophagy. We show that reduced maturation of Pep4 in a VPS10-deletion strain affects the proteolytic activity of the vacuole depending on the type and amount of substrate. The VPS10-deletion has no effect on the degradation of the cytosolic protein Pgk1 via bulk autophagy or on the degradation of ribosomes via ribophagy. In contrast, the degradation of an excess of peroxisomes via pexophagy as well as mitochondria via mitophagy was significantly hampered in a VPS10-deletion strain and correlated with a decreased maturation level of Pep4. The results show that Vps10-mediated targeting of Pep4 limits the proteolytic capacity of the vacuole in a substrate-dependent manner.
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Affiliation(s)
- Fahd Boutouja
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, 44801, Bochum, Germany
| | - Christian M Stiehm
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, 44801, Bochum, Germany
| | - Thomas Mastalski
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, 44801, Bochum, Germany
| | - Rebecca Brinkmeier
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, 44801, Bochum, Germany
| | - Christina Reidick
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, 44801, Bochum, Germany
| | - Fouzi El Magraoui
- Biomedizinische Forschung, Leibniz-Institute for Analytical Sciences (ISAS-e.V.), 44139, Dortmund, Germany
| | - Harald W Platta
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, 44801, Bochum, Germany.
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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. Biochim Biophys Acta Mol Cell Res 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] [What about the content of this article? (0)] [Affiliation(s)] [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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Platta HW, Brinkmeier R, Reidick C, Galiani S, Clausen MP, Eggeling C. Regulation of peroxisomal matrix protein import by ubiquitination. Biochim Biophys Acta 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] [What about the content of this article? (0)] [Affiliation(s)] [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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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] [What about the content of this article? (0)] [Affiliation(s)] [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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El Magraoui F, Brinkmeier R, Schrötter A, Girzalsky W, Müller T, Marcus K, Meyer HE, Erdmann R, Platta HW. Distinct Ubiquitination Cascades Act on the Peroxisomal Targeting Signal Type 2 Co-receptor Pex18p. Traffic 2013; 14:1290-301. [DOI: 10.1111/tra.12120] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 09/09/2013] [Accepted: 09/11/2013] [Indexed: 01/29/2023]
Affiliation(s)
- Fouzi El Magraoui
- Biochemie Intrazellulärer Transportprozesse; Ruhr-Universität Bochum; Bochum 44780 Germany
- Systembiochemie; Ruhr-Universität Bochum; Bochum 44780 Germany
- Medizinische Proteomik/Bioanalytik, AG Neuro Proteomics; Medizinisches Proteom-Center; Bochum 44801 Germany
| | - Rebecca Brinkmeier
- Biochemie Intrazellulärer Transportprozesse; Ruhr-Universität Bochum; Bochum 44780 Germany
| | - Andreas Schrötter
- Medizinische Proteomik/Bioanalytik, AG Neuro Proteomics; Medizinisches Proteom-Center; Bochum 44801 Germany
| | | | - Thorsten Müller
- Funktionelle Proteomik; Medizinisches Proteom-Center; Bochum 44801 Germany
| | - Katrin Marcus
- Funktionelle Proteomik; Medizinisches Proteom-Center; Bochum 44801 Germany
| | - Helmut E. Meyer
- Medizinische Proteomik/Bioanalytik; Medizinisches Proteom-Center; Bochum 44801 Germany
| | - Ralf Erdmann
- Systembiochemie; Ruhr-Universität Bochum; Bochum 44780 Germany
| | - Harald W. Platta
- Biochemie Intrazellulärer Transportprozesse; Ruhr-Universität Bochum; Bochum 44780 Germany
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