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You X, Zhu S, Sheng H, Liu Z, Wang D, Wang M, Xu X, He F, Fang H, Zhang F, Wang D, Hao Z, Wang R, Xiao Y, Wan J, Wang GL, Ning Y. The rice peroxisomal receptor PEX5 negatively regulates resistance to rice blast fungus Magnaporthe oryzae. Cell Rep 2023; 42:113315. [PMID: 37862164 DOI: 10.1016/j.celrep.2023.113315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 08/22/2023] [Accepted: 10/06/2023] [Indexed: 10/22/2023] Open
Abstract
The receptor protein PEX5, an important component of peroxisomes, regulates growth, development, and immunity in yeast and mammals. PEX5 also influences growth and development in plants, but whether it participates in plant immunity has remained unclear. Here, we report that knockdown of OsPEX5 enhances resistance to the rice blast fungus Magnaporthe oryzae. We demonstrate that OsPEX5 interacts with the E3 ubiquitin ligase APIP6, a positive regulator of plant immunity. APIP6 ubiquitinates OsPEX5 in vitro and promotes its degradation in vivo via the 26S proteasome pathway. In addition, OsPEX5 interacts with the aldehyde dehydrogenase OsALDH2B1, which functions in growth-defense trade-offs in rice. OsPEX5 stabilizes OsALDH2B1 to enhance its repression of the defense-related gene OsAOS2. Our study thus uncovers a previously unrecognized hierarchical regulatory mechanism in which an E3 ubiquitin ligase targets a peroxisome receptor protein that negatively regulates immunity in rice by stabilizing an aldehyde dehydrogenase that suppresses defense gene expression.
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Affiliation(s)
- Xiaoman You
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Shanshan Zhu
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agriculture Sciences, Beijing 100081, China
| | - Haowen Sheng
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; College of Agronomy, Hunan Agricultural University, Changsha, China
| | - Zheng Liu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Dan Wang
- College of Agronomy, Hunan Agricultural University, Changsha, China
| | - Min Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Xiao Xu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Feng He
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Hong Fang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Fan Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Debao Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Zeyun Hao
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Ruyi Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Yinghui Xiao
- College of Agronomy, Hunan Agricultural University, Changsha, China
| | - Jianmin Wan
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agriculture Sciences, Beijing 100081, China
| | - Guo-Liang Wang
- Department of Plant Pathology, The Ohio State University, Columbus, OH 43210, USA
| | - Yuese Ning
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
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Brechting PJ, Shah C, Rakotondraibe L, Shen Q, Rappleye CA. Histoplasma capsulatum requires peroxisomes for multiple virulence functions including siderophore biosynthesis. mBio 2023; 14:e0328422. [PMID: 37432032 PMCID: PMC10470777 DOI: 10.1128/mbio.03284-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 05/30/2023] [Indexed: 07/12/2023] Open
Abstract
Peroxisomes are versatile eukaryotic organelles essential for many functions in fungi, including fatty acid metabolism, reactive oxygen species detoxification, and secondary metabolite biosynthesis. A suite of Pex proteins (peroxins) maintains peroxisomes, while peroxisomal matrix enzymes execute peroxisome functions. Insertional mutagenesis identified peroxin genes as essential components supporting the intraphagosomal growth of the fungal pathogen Histoplasma capsulatum. Disruption of the peroxins Pex5, Pex10, or Pex33 in H. capsulatum prevented peroxisome import of proteins targeted to the organelle via the PTS1 pathway. This loss of peroxisome protein import limited H. capsulatum intracellular growth in macrophages and attenuated virulence in an acute histoplasmosis infection model. Interruption of the alternate PTS2 import pathway also attenuated H. capsulatum virulence, although only at later time points of infection. The Sid1 and Sid3 siderophore biosynthesis proteins contain a PTS1 peroxisome import signal and localize to the H. capsulatum peroxisome. Loss of either the PTS1 or PTS2 peroxisome import pathway impaired siderophore production and iron acquisition in H. capsulatum, demonstrating compartmentalization of at least some biosynthetic steps for hydroxamate siderophore biosynthesis. However, the loss of PTS1-based peroxisome import caused earlier virulence attenuation than either the loss of PTS2-based protein import or the loss of siderophore biosynthesis, indicating additional PTS1-dependent peroxisomal functions are important for H. capsulatum virulence. Furthermore, disruption of the Pex11 peroxin also attenuated H. capsulatum virulence independently of peroxisomal protein import and siderophore biosynthesis. These findings demonstrate peroxisomes contribute to H. capsulatum pathogenesis by facilitating siderophore biosynthesis and another unidentified role(s) for the organelle during fungal virulence. IMPORTANCE The fungal pathogen Histoplasma capsulatum infects host phagocytes and establishes a replication-permissive niche within the cells. To do so, H. capsulatum overcomes and subverts antifungal defense mechanisms which include the limitation of essential micronutrients. H. capsulatum replication within host cells requires multiple distinct functions of the fungal peroxisome organelle. These peroxisomal functions contribute to H. capsulatum pathogenesis at different times during infection and include peroxisome-dependent biosynthesis of iron-scavenging siderophores to enable fungal proliferation, particularly after activation of cell-mediated immunity. The multiple essential roles of fungal peroxisomes reveal this organelle as a potential but untapped target for the development of therapeutics.
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Affiliation(s)
| | - Chandan Shah
- Department of Microbiology, Ohio State University, Columbus, Ohio, USA
| | - Liva Rakotondraibe
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, Ohio State University, Columbus, Ohio, USA
| | - Qian Shen
- Department of Biology, Rhodes College, Memphis, Tennessee, USA
| | - Chad A. Rappleye
- Department of Microbiology, Ohio State University, Columbus, Ohio, USA
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Feng P, Skowyra ML, Rapoport TA. Structure and function of the peroxisomal ubiquitin ligase complex. Biochem Soc Trans 2022; 50:1921-1930. [PMID: 36421406 PMCID: PMC9788354 DOI: 10.1042/bst20221393] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 11/10/2022] [Accepted: 11/14/2022] [Indexed: 09/26/2023]
Abstract
Peroxisomes are membrane-bounded organelles that exist in most eukaryotic cells and are involved in the oxidation of fatty acids and the destruction of reactive oxygen species. Depending on the organism, they house additional metabolic reactions that range from glycolysis in parasitic protozoa to the production of ether lipids in animals and antibiotics in fungi. The importance of peroxisomes for human health is revealed by various disorders - notably the Zellweger spectrum - that are caused by defects in peroxisome biogenesis and are often fatal. Most peroxisomal metabolic enzymes reside in the lumen, but are synthesized in the cytosol and imported into the organelle by mobile receptors. The receptors accompany cargo all the way into the lumen and must return to the cytosol to start a new import cycle. Recycling requires receptor monoubiquitination by a membrane-embedded ubiquitin ligase complex composed of three RING finger (RF) domain-containing proteins: PEX2, PEX10, and PEX12. A recent cryo-electron microscopy (cryo-EM) structure of the complex reveals its function as a retro-translocation channel for peroxisomal import receptors. Each subunit of the complex contributes five transmembrane segments that assemble into an open channel. The N terminus of a receptor likely inserts into the pore from the lumenal side, and is then monoubiquitinated by one of the RFs to enable extraction into the cytosol. If recycling is compromised, receptors are polyubiquitinated by the concerted action of the other two RFs and ultimately degraded. The new data provide mechanistic insight into a crucial step of peroxisomal protein import.
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Affiliation(s)
- Peiqiang Feng
- Howard Hughes Medical Institute and Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, Massachusetts 02115, U.S.A
| | - Michael L. Skowyra
- Howard Hughes Medical Institute and Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, Massachusetts 02115, U.S.A
| | - Tom A. Rapoport
- Howard Hughes Medical Institute and Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, Massachusetts 02115, U.S.A
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Feng P, Wu X, Erramilli SK, Paulo JA, Knejski P, Gygi SP, Kossiakoff AA, Rapoport TA. A peroxisomal ubiquitin ligase complex forms a retrotranslocation channel. Nature 2022; 607:374-380. [PMID: 35768507 PMCID: PMC9279156 DOI: 10.1038/s41586-022-04903-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 05/25/2022] [Indexed: 01/04/2023]
Abstract
Peroxisomes are ubiquitous organelles that house various metabolic reactions and are essential for human health1–4. Luminal peroxisomal proteins are imported from the cytosol by mobile receptors, which then recycle back to the cytosol by a poorly understood process1–4. Recycling requires receptor modification by a membrane-embedded ubiquitin ligase complex comprising three RING finger domain-containing proteins (Pex2, Pex10 and Pex12)5,6. Here we report a cryo-electron microscopy structure of the ligase complex, which together with biochemical and in vivo experiments reveals its function as a retrotranslocation channel for peroxisomal import receptors. Each subunit of the complex contributes five transmembrane segments that co-assemble into an open channel. The three ring finger domains form a cytosolic tower, with ring finger 2 (RF2) positioned above the channel pore. We propose that the N terminus of a recycling receptor is inserted from the peroxisomal lumen into the pore and monoubiquitylated by RF2 to enable extraction into the cytosol. If recycling is compromised, receptors are polyubiquitylated by the concerted action of RF10 and RF12 and degraded. This polyubiquitylation pathway also maintains the homeostasis of other peroxisomal import factors. Our results clarify a crucial step during peroxisomal protein import and reveal why mutations in the ligase complex cause human disease. The cryo-electron microscopy structure of the membrane-embedded ubiquitin ligase complex reveals its function as a retrotranslocation channel for shuttling mobile receptors out of peroxisomes.
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Affiliation(s)
- Peiqiang Feng
- Department of Cell Biology, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, USA.
| | - Xudong Wu
- Department of Cell Biology, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, USA
| | - Satchal K Erramilli
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, USA
| | - Joao A Paulo
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Pawel Knejski
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, USA
| | - Steven P Gygi
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Anthony A Kossiakoff
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, USA.,Institute for Biophysical Dynamics, University of Chicago, Chicago, IL, USA
| | - Tom A Rapoport
- Department of Cell Biology, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, USA.
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Yu H, Kamber RA, Denic V. The peroxisomal exportomer directly inhibits phosphoactivation of the pexophagy receptor Atg36 to suppress pexophagy in yeast. eLife 2022; 11:74531. [PMID: 35404228 PMCID: PMC9000956 DOI: 10.7554/elife.74531] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 03/09/2022] [Indexed: 01/21/2023] Open
Abstract
Autophagy receptor (or adaptor) proteins facilitate lysosomal destruction of various organelles in response to cellular stress, including nutrient deprivation. To what extent membrane-resident autophagy receptors also respond to organelle-restricted cues to induce selective autophagy remains poorly understood. We find that latent activation of the yeast pexophagy receptor Atg36 by the casein kinase Hrr25 in rich media is repressed by the ATPase activity of Pex1/6, the catalytic subunits of the exportomer AAA+ transmembrane complex enabling protein import into peroxisomes. Quantitative proteomics of purified Pex3, an obligate Atg36 coreceptor, support a model in which the exportomer tail anchored to the peroxisome membrane represses Atg36 phosphorylation on Pex3 without assistance from additional membrane factors. Indeed, we reconstitute inhibition of Atg36 phosphorylation in vitro using soluble Pex1/6 and define an N-terminal unstructured region of Atg36 that enables regulation by binding to Pex1. Our findings uncover a mechanism by which a compartment-specific AAA+ complex mediating organelle biogenesis and protein quality control staves off induction of selective autophagy.
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Affiliation(s)
- Houqing Yu
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States
| | - Roarke A Kamber
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States
| | - Vladimir Denic
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States
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Wang Y, Li J, Zhao F, Zhang Y, Yang X, Lin Y, Han S. Methanol oxidase from Hansenula polymorpha shows activity in peroxisome-deficient Pichia pastoris. Biochem Eng J 2022. [DOI: 10.1016/j.bej.2022.108369] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Yu W, Lin M, Peng M, Yan H, Wang J, Zhou J, Lu G, Wang Z, Shim WB. Fusarium verticillioides FvPex8 Is a Key Component of the Peroxisomal Docking/Translocation Module That Serves Important Roles in Fumonisin Biosynthesis but Not in Virulence. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2021; 34:803-814. [PMID: 33749306 DOI: 10.1094/mpmi-10-20-0273-r] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Peroxisomes are ubiquitous organelles in eukaryotes that fulfill various important metabolic functions. In this study, we investigated the role of docking/translocation module (DTM) peroxins, mainly FvPex8, FvPex13, FvPex14, and FvPex33, in Fusarium verticillioides development, virulence, and fumonisin B1 (FB1) biosynthesis. Protein interaction experiments suggested that FvPex13 serves as the central DTM subunit in F. verticillioides. Notably, FvPex8 and FvPex14 did not show direct interaction in our experiments. We generated gene-deletion mutants (ΔFvpex8, ΔFvpex13, ΔFvpex14, ΔFvpex33, ΔFvpex33/14) and further examined the functional role of these peroxins. Deletion mutants exhibited disparity in carbon nutrient utilization and defect in cell-wall integrity when stress agents were applied. Under nutrient starvation, mutants also showed higher levels of lipid droplet accumulation. Particularly, ΔFvpex8 mutant showed significant FB1 reduction and altered expression of key FB1 biosynthesis genes. However, FvPex13 was primarily responsible for asexual conidia reproduction and virulence, while the ΔFvpex33/14 double mutant also showed a virulence defect. In summary, our study suggests that FvPex13 is the central component of DTM, with direct physical interaction with other DTM peroxins, and regulates peroxisome membrane biogenesis as well as PTS1- and PTS2-mediated transmembrane cargo transportation. Importantly, we also characterized FvPex8 as a key component in F. verticillioides DTM that affects peroxisome function and FB1 biosynthesis.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Wenying Yu
- Key Laboratory of Biopesticide and Chemical Biology of Ministry of Education & Fujian Universities Key Laboratory for Plant-Microbe Interaction, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Mei Lin
- Key Laboratory of Biopesticide and Chemical Biology of Ministry of Education & Fujian Universities Key Laboratory for Plant-Microbe Interaction, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Minghui Peng
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Huijuan Yan
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843-2132, U.S.A
| | - Jiajia Wang
- Key Laboratory of Biopesticide and Chemical Biology of Ministry of Education & Fujian Universities Key Laboratory for Plant-Microbe Interaction, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Jie Zhou
- Key Laboratory of Biopesticide and Chemical Biology of Ministry of Education & Fujian Universities Key Laboratory for Plant-Microbe Interaction, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Guodong Lu
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Zonghua Wang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Won Bo Shim
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843-2132, U.S.A
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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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Farré JC, Mahalingam SS, Proietto M, Subramani S. Peroxisome biogenesis, membrane contact sites, and quality control. EMBO Rep 2018; 20:embr.201846864. [PMID: 30530632 DOI: 10.15252/embr.201846864] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Revised: 10/08/2018] [Accepted: 11/16/2018] [Indexed: 12/19/2022] Open
Abstract
Peroxisomes are conserved organelles of eukaryotic cells with important roles in cellular metabolism, human health, redox homeostasis, as well as intracellular metabolite transfer and signaling. We review here the current status of the different co-existing modes of biogenesis of peroxisomal membrane proteins demonstrating the fascinating adaptability in their targeting and sorting pathways. While earlier studies focused on peroxisomes as autonomous organelles, the necessity of the ER and potentially even mitochondria as sources of peroxisomal membrane proteins and lipids has come to light in recent years. Additionally, the intimate physical juxtaposition of peroxisomes with other organelles has transitioned from being viewed as random encounters to a growing appreciation of the expanding roles of such inter-organellar membrane contact sites in metabolic and regulatory functions. Peroxisomal quality control mechanisms have also come of age with a variety of mechanisms operating both during biogenesis and in the cellular response to environmental cues.
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Affiliation(s)
- Jean-Claude Farré
- Section of Molecular Biology, Division of Biological Sciences, University of California, San Diego, CA, USA
| | - Shanmuga S Mahalingam
- Section of Molecular Biology, Division of Biological Sciences, University of California, San Diego, CA, USA
| | - Marco Proietto
- Section of Molecular Biology, Division of Biological Sciences, University of California, San Diego, CA, USA
| | - Suresh Subramani
- Section of Molecular Biology, Division of Biological Sciences, University of California, San Diego, CA, USA
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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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Zhang F, Geng L, Huang L, Deng J, Fasoyin OE, Yao G, Wang S. Contribution of peroxisomal protein importer AflPex5 to development and pathogenesis in the fungus Aspergillus flavus. Curr Genet 2018; 64:1335-1348. [PMID: 29869688 DOI: 10.1007/s00294-018-0851-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 05/31/2018] [Accepted: 06/01/2018] [Indexed: 10/14/2022]
Abstract
Peroxisomes are important organelles that have diverse metabolic functions and participate in the pathogenicity of fungal pathogens. Previous studies indicate that most functions of peroxisomes are dependent on peroxisomal matrix proteins, which are delivered from the cytoplasm into peroxisomes by peroxisomal protein importers. In this study, the roles of peroxisomal protein importer AflPex5 were investigated in Aspergillus flavus with the application of gene disruption. AflPex5 deletion mutants failed to localize the fluorescently fused peroxisomal targeting signal 1 (PTS1) proteins to peroxisomes. Deletion of AflPex5 caused defects in sporulation, sclerotial formation, aflatoxin biosynthesis, stress response, and plant infection. Moreover, AflPex5 null mutants exhibited a significant defect in carbon metabolism and oxidants' clearance. These results indicate that the PTS1 pathway mediated by AflPex5 serves as an important role in the development, metabolism, and pathogenesis of A. flavus.
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Affiliation(s)
- Feng Zhang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Longpo Geng
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Luhua Huang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jili Deng
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Opemipo Esther Fasoyin
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Guangshan Yao
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Shihua Wang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China.
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12
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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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13
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Zolezzi JM, Santos MJ, Bastías-Candia S, Pinto C, Godoy JA, Inestrosa NC. PPARs in the central nervous system: roles in neurodegeneration and neuroinflammation. Biol Rev Camb Philos Soc 2017; 92:2046-2069. [PMID: 28220655 DOI: 10.1111/brv.12320] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 12/21/2016] [Accepted: 01/11/2017] [Indexed: 12/20/2022]
Abstract
Over 25 years have passed since peroxisome proliferators-activated receptors (PPARs), were first described. Like other members of the nuclear receptors superfamily, PPARs have been defined as critical sensors and master regulators of cellular metabolism. Recognized as ligand-activated transcription factors, they are involved in lipid, glucose and amino acid metabolism, taking part in different cellular processes, including cellular differentiation and apoptosis, inflammatory modulation and attenuation of acute and chronic neurological damage in vivo and in vitro. Interestingly, PPAR activation can simultaneously reprogram the immune response, stimulate metabolic and mitochondrial functions, promote axonal growth, induce progenitor cells to differentiate into myelinating oligodendrocytes, and improve brain clearance of toxic molecules such as β-amyloid peptide. Although the molecular mechanisms and cross-talk with different molecular pathways are still the focus of intense research, PPARs are considered potential therapeutic targets for several neuropathological conditions, including degenerative disorders such as Alzheimer's, Parkinson's and Huntington's disease. This review considers recent advances regarding PPARs, as well as new PPAR agonists. We focus on the mechanisms behind the neuroprotective effects exerted by PPARs and summarise the roles of PPARs in different pathologies of the central nervous system, especially those associated with degenerative and inflammatory mechanisms.
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Affiliation(s)
- Juan M Zolezzi
- Centro de Envejecimiento y Regeneración (CARE-UC), P. Catholic University of Chile, PO Box 114-D, 8331150, Santiago, Chile
| | - Manuel J Santos
- Facultad de Ciencias Biológicas, Departamento de Biología Celular y Molecular, Pontificia Universidad Católica de Chile, Alameda 340, 8331150, Santiago, Chile
| | - Sussy Bastías-Candia
- Facultad de Ciencias, Departamento de Biología, Universidad de Tarapacá, Gral. Velásquez 1775, 1000007, Arica, Chile
| | - Claudio Pinto
- Centro de Envejecimiento y Regeneración (CARE-UC), P. Catholic University of Chile, PO Box 114-D, 8331150, Santiago, Chile
| | - Juan A Godoy
- Centro de Envejecimiento y Regeneración (CARE-UC), P. Catholic University of Chile, PO Box 114-D, 8331150, Santiago, Chile.,Facultad de Ciencias Biológicas, Departamento de Biología Celular y Molecular, Pontificia Universidad Católica de Chile, Alameda 340, 8331150, Santiago, Chile
| | - Nibaldo C Inestrosa
- Centro de Envejecimiento y Regeneración (CARE-UC), P. Catholic University of Chile, PO Box 114-D, 8331150, Santiago, Chile.,Facultad de Ciencias Biológicas, Departamento de Biología Celular y Molecular, Pontificia Universidad Católica de Chile, Alameda 340, 8331150, Santiago, Chile.,Faculty of Medicine, Centre for Healthy Brain Ageing, School of Psychiatry, University of New South Wales, Avoca Street Randwick NSW 2031, Sydney, Australia.,Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes, PO Box 113-D, Avenida Bulnes 01855, 6210427, Punta Arenas, Chile
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14
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Seppälä S, Solomon KV, Gilmore SP, Henske JK, O'Malley MA. Mapping the membrane proteome of anaerobic gut fungi identifies a wealth of carbohydrate binding proteins and transporters. Microb Cell Fact 2016; 15:212. [PMID: 27998268 PMCID: PMC5168858 DOI: 10.1186/s12934-016-0611-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 12/02/2016] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Engineered cell factories that convert biomass into value-added compounds are emerging as a timely alternative to petroleum-based industries. Although often overlooked, integral membrane proteins such as solute transporters are pivotal for engineering efficient microbial chassis. Anaerobic gut fungi, adapted to degrade raw plant biomass in the intestines of herbivores, are a potential source of valuable transporters for biotechnology, yet very little is known about the membrane constituents of these non-conventional organisms. Here, we mined the transcriptome of three recently isolated strains of anaerobic fungi to identify membrane proteins responsible for sensing and transporting biomass hydrolysates within a competitive and rather extreme environment. RESULTS Using sequence analyses and homology, we identified membrane protein-coding sequences from assembled transcriptomes from three strains of anaerobic gut fungi: Neocallimastix californiae, Anaeromyces robustus, and Piromyces finnis. We identified nearly 2000 transporter components: about half of these are involved in the general secretory pathway and intracellular sorting of proteins; the rest are predicted to be small-solute transporters. Unexpectedly, we found a number of putative sugar binding proteins that are associated with prokaryotic uptake systems; and approximately 100 class C G-protein coupled receptors (GPCRs) with non-canonical putative sugar binding domains. CONCLUSIONS We report the first comprehensive characterization of the membrane protein machinery of biotechnologically relevant anaerobic gut fungi. Apart from identifying conserved machinery for protein sorting and secretion, we identify a large number of putative solute transporters that are of interest for biotechnological applications. Notably, our data suggests that the fungi display a plethora of carbohydrate binding domains at their surface, perhaps as a means to sense and sequester some of the sugars that their biomass degrading, extracellular enzymes produce.
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Affiliation(s)
- Susanna Seppälä
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet Bygning 220, 2800, Kgs. Lyngby, Denmark.,Department of Chemical Engineering, University of California, Santa Barbara, CA, 93106, USA
| | - Kevin V Solomon
- Department of Chemical Engineering, University of California, Santa Barbara, CA, 93106, USA.,Agricultural and Biological Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Sean P Gilmore
- Department of Chemical Engineering, University of California, Santa Barbara, CA, 93106, USA
| | - John K Henske
- Department of Chemical Engineering, University of California, Santa Barbara, CA, 93106, USA
| | - Michelle A O'Malley
- Department of Chemical Engineering, University of California, Santa Barbara, CA, 93106, USA.
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15
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Reumann S, Bartel B. Plant peroxisomes: recent discoveries in functional complexity, organelle homeostasis, and morphological dynamics. CURRENT OPINION IN PLANT BIOLOGY 2016; 34:17-26. [PMID: 27500947 PMCID: PMC5161562 DOI: 10.1016/j.pbi.2016.07.008] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2016] [Revised: 07/15/2016] [Accepted: 07/20/2016] [Indexed: 05/20/2023]
Abstract
Peroxisomes are essential for life in plants. These organelles house a variety of metabolic processes that generate and inactivate reactive oxygen species. Our knowledge of pathways and mechanisms that depend on peroxisomes and their constituent enzymes continues to grow, and in this review we highlight recent advances in understanding the identity and biological functions of peroxisomal enzymes and metabolic processes. We also review how peroxisomal matrix and membrane proteins enter the organelle from their sites of synthesis. Peroxisome homeostasis is regulated by specific degradation mechanisms, and we discuss the contributions of specialized autophagy and a peroxisomal protease to the degradation of entire peroxisomes and peroxisomal enzymes that are damaged or superfluous. Finally, we review how peroxisomes can flexibly change their morphology to facilitate inter-organellar contacts.
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Affiliation(s)
- Sigrun Reumann
- Department of Plant Biochemistry and Infection Biology, Biocentre Klein Flottbek, University of Hamburg, D-22609 Hamburg, Germany; Centre for Organelle Research, Faculty of Science and Technology, University of Stavanger, N-4036 Stavanger, Norway
| | - Bonnie Bartel
- Department of BioSciences, Rice University, Houston, TX 77005, USA.
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16
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Nordgren M, Francisco T, Lismont C, Hennebel L, Brees C, Wang B, Van Veldhoven PP, Azevedo JE, Fransen M. Export-deficient monoubiquitinated PEX5 triggers peroxisome removal in SV40 large T antigen-transformed mouse embryonic fibroblasts. Autophagy 2016; 11:1326-40. [PMID: 26086376 DOI: 10.1080/15548627.2015.1061846] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Peroxisomes are ubiquitous cell organelles essential for human health. To maintain a healthy cellular environment, dysfunctional and superfluous peroxisomes need to be selectively removed. Although emerging evidence suggests that peroxisomes are mainly degraded by pexophagy, little is known about the triggers and molecular mechanisms underlying this process in mammalian cells. In this study, we show that PEX5 proteins fused to a bulky C-terminal tag trigger peroxisome degradation in SV40 large T antigen-transformed mouse embryonic fibroblasts. In addition, we provide evidence that this process is autophagy-dependent and requires monoubiquitination of the N-terminal cysteine residue that marks PEX5 for recycling. As our findings also demonstrate that the addition of a bulky tag to the C terminus of PEX5 does not interfere with PEX5 monoubiquitination but strongly inhibits its export from the peroxisomal membrane, we hypothesize that such a tag mimics a cargo protein that cannot be released from PEX5, thus keeping monoubiquitinated PEX5 at the membrane for a sufficiently long time to be recognized by the autophagic machinery. This in turn suggests that monoubiquitination of the N-terminal cysteine of peroxisome-associated PEX5 not only functions to recycle the peroxin back to the cytosol, but also serves as a quality control mechanism to eliminate peroxisomes with a defective protein import machinery.
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Affiliation(s)
- Marcus Nordgren
- a Laboratory of Lipid Biochemistry and Protein Interactions; Department of Cellular and Molecular Medicine; University of Leuven - KU Leuven ; Leuven , Belgium
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17
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Emmanouilidis L, Gopalswamy M, Passon DM, Wilmanns M, Sattler M. Structural biology of the import pathways of peroxisomal matrix proteins. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:804-13. [DOI: 10.1016/j.bbamcr.2015.09.034] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 09/29/2015] [Accepted: 09/30/2015] [Indexed: 11/28/2022]
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18
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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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19
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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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20
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Choudhry SK, Kawałek A, van der Klei IJ. Peroxisomal quality control mechanisms. Curr Opin Microbiol 2014; 22:30-7. [PMID: 25305535 DOI: 10.1016/j.mib.2014.09.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 09/08/2014] [Accepted: 09/12/2014] [Indexed: 10/24/2022]
Abstract
Peroxisomes are ubiquitous organelles that harbor diverse metabolic pathways, which are essential for normal cell performance. Conserved functions of these organelles are hydrogen peroxide metabolism and β-oxidation. Cells employ multiple quality control mechanisms to ensure proper peroxisome function and to protect peroxisomes from damage. These involve the function of molecular chaperones, a peroxisomal Lon protease and autophagic removal of dysfunctional organelles. In addition, multiple mechanisms exist to combat peroxisomal oxidative stress. Here, we outline recent advances in our understanding of peroxisomal quality control, focussing on yeast and filamentous fungi.
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Affiliation(s)
- Sanjeev K Choudhry
- Molecular Cell Biology, Groningen Biomolecular Sciences and Biotechnology Institute, Systems Biology Centre for Energy Metabolism and Ageing, University of Groningen, P.O. Box 11103, 9300CC Groningen, The Netherlands
| | - Adam Kawałek
- Molecular Cell Biology, Groningen Biomolecular Sciences and Biotechnology Institute, Systems Biology Centre for Energy Metabolism and Ageing, University of Groningen, P.O. Box 11103, 9300CC Groningen, The Netherlands
| | - Ida J van der Klei
- Molecular Cell Biology, Groningen Biomolecular Sciences and Biotechnology Institute, Systems Biology Centre for Energy Metabolism and Ageing, University of Groningen, P.O. Box 11103, 9300CC Groningen, The Netherlands.
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21
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Burkhart SE, Kao YT, Bartel B. Peroxisomal ubiquitin-protein ligases peroxin2 and peroxin10 have distinct but synergistic roles in matrix protein import and peroxin5 retrotranslocation in Arabidopsis. PLANT PHYSIOLOGY 2014; 166:1329-44. [PMID: 25214533 PMCID: PMC4226347 DOI: 10.1104/pp.114.247148] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Accepted: 09/11/2014] [Indexed: 05/20/2023]
Abstract
Peroxisomal matrix proteins carry peroxisomal targeting signals (PTSs), PTS1 or PTS2, and are imported into the organelle with the assistance of peroxin (PEX) proteins. From a microscopy-based screen to identify Arabidopsis (Arabidopsis thaliana) mutants defective in matrix protein degradation, we isolated unique mutations in PEX2 and PEX10, which encode ubiquitin-protein ligases anchored in the peroxisomal membrane. In yeast (Saccharomyces cerevisiae), PEX2, PEX10, and a third ligase, PEX12, ubiquitinate a peroxisome matrix protein receptor, PEX5, allowing the PEX1 and PEX6 ATP-hydrolyzing enzymes to retrotranslocate PEX5 out of the membrane after cargo delivery. We found that the pex2-1 and pex10-2 Arabidopsis mutants exhibited defects in peroxisomal physiology and matrix protein import. Moreover, the pex2-1 pex10-2 double mutant exhibited severely impaired growth and synergistic physiological defects, suggesting that PEX2 and PEX10 function cooperatively in the wild type. The pex2-1 lesion restored the unusually low PEX5 levels in the pex6-1 mutant, implicating PEX2 in PEX5 degradation when retrotranslocation is impaired. PEX5 overexpression altered pex10-2 but not pex2-1 defects, suggesting that PEX10 facilitates PEX5 retrotranslocation from the peroxisomal membrane. Although the pex2-1 pex10-2 double mutant displayed severe import defects of both PTS1 and PTS2 proteins into peroxisomes, both pex2-1 and pex10-2 single mutants exhibited clear import defects of PTS1 proteins but apparently normal PTS2 import. A similar PTS1-specific pattern was observed in the pex4-1 ubiquitin-conjugating enzyme mutant. Our results indicate that Arabidopsis PEX2 and PEX10 cooperate to support import of matrix proteins into plant peroxisomes and suggest that some PTS2 import can still occur when PEX5 retrotranslocation is slowed.
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Affiliation(s)
- Sarah E Burkhart
- Department of BioSciences, Rice University, Houston, Texas 77005
| | - Yun-Ting Kao
- Department of BioSciences, Rice University, Houston, Texas 77005
| | - Bonnie Bartel
- Department of BioSciences, Rice University, Houston, Texas 77005
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22
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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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23
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Sommer MS, Schleiff E. Protein targeting and transport as a necessary consequence of increased cellular complexity. Cold Spring Harb Perspect Biol 2014; 6:6/8/a016055. [PMID: 25085907 DOI: 10.1101/cshperspect.a016055] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
With increasing intracellular complexity, a new cell-biological problem that is the allocation of cytoplasmically synthesized proteins to their final destinations within the cell emerged. A special challenge is thereby the translocation of proteins into or across cellular membranes. The underlying mechanisms are only in parts well understood, but it can be assumed that the course of cellular evolution had a deep impact on the design of the required molecular machines. In this article, we aim to summarize the current knowledge and concepts of the evolutionary development of protein trafficking as a necessary premise and consequence of increased cellular complexity.
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Affiliation(s)
- Maik S Sommer
- Institute for Molecular Biosciences, Department of Biosciences, Molecular Cell Biology of Plants, Goethe University Frankfurt am Main, D-60438 Frankfurt, Germany
| | - Enrico Schleiff
- Institute for Molecular Biosciences, Department of Biosciences, Molecular Cell Biology of Plants, Goethe University Frankfurt am Main, D-60438 Frankfurt, Germany Cluster of Excellence Macromolecular Complexes, Goethe University Frankfurt am Main, D-60438 Frankfurt, Germany Centre of Membrane Proteomics, Goethe University Frankfurt am Main, D-60438 Frankfurt, Germany
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24
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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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25
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Hettema EH, Erdmann R, van der Klei I, Veenhuis M. Evolving models for peroxisome biogenesis. Curr Opin Cell Biol 2014; 29:25-30. [PMID: 24681485 PMCID: PMC4148619 DOI: 10.1016/j.ceb.2014.02.002] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 02/18/2014] [Accepted: 02/21/2014] [Indexed: 12/11/2022]
Abstract
Significant progress has been made towards our understanding of the mechanism of peroxisome formation, in particular concerning sorting of peroxisomal membrane proteins, matrix protein import and organelle multiplication. Here we evaluate the progress made in recent years. We focus mainly on progress made in yeasts. We indicate the gaps in our knowledge and discuss conflicting models.
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Affiliation(s)
- Ewald H Hettema
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK.
| | - Ralf Erdmann
- System Biochie, Ruhr Universitat Bochum, Universitatstr. 150, D-44780, Bochum, Germany
| | - Ida van der Klei
- Molecular Cell Biology, Groningen Biomolecular Sciences and Biotechnology institute, University of Groningen, 11 103, 9700CC, Groningen, The Netherlands
| | - Marten Veenhuis
- Molecular Cell Biology, Groningen Biomolecular Sciences and Biotechnology institute, University of Groningen, 11 103, 9700CC, Groningen, The Netherlands
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26
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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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27
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Abstract
Peroxisomes carry out various oxidative reactions that are tightly regulated to adapt to the changing needs of the cell and varying external environments. Accordingly, they are remarkably fluid and can change dramatically in abundance, size, shape and content in response to numerous cues. These dynamics are controlled by multiple aspects of peroxisome biogenesis that are coordinately regulated with each other and with other cellular processes. Ongoing studies are deciphering the diverse molecular mechanisms that underlie biogenesis and how they cooperate to dynamically control peroxisome utility. These important challenges should lead to an understanding of peroxisome dynamics that can be capitalized upon for bioengineering and the development of therapies to improve human health.
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Affiliation(s)
- Jennifer J Smith
- 1] Seattle Biomedical Research Institute, 307 Westlake Avenue North, 98109-5240, USA. [2] Institute for Systems Biology, 401 Terry Avenue North, Seattle, Washington 98109-5219, USA
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28
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Brown AI, Kim PK, Rutenberg AD. PEX5 and ubiquitin dynamics on mammalian peroxisome membranes. PLoS Comput Biol 2014; 10:e1003426. [PMID: 24453954 PMCID: PMC3894153 DOI: 10.1371/journal.pcbi.1003426] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 11/19/2013] [Indexed: 12/04/2022] Open
Abstract
Peroxisomes are membrane-bound organelles within eukaryotic cells that post-translationally import folded proteins into their matrix. Matrix protein import requires a shuttle receptor protein, usually PEX5, that cycles through docking with the peroxisomal membrane, ubiquitination, and export back into the cytosol followed by deubiquitination. Matrix proteins associate with PEX5 in the cytosol and are translocated into the peroxisome lumen during the PEX5 cycle. This cargo translocation step is not well understood, and its energetics remain controversial. We use stochastic computational models to explore different ways the AAA ATPase driven removal of PEX5 may couple with cargo translocation in peroxisomal importers of mammalian cells. The first model considered is uncoupled, in which translocation is spontaneous, and does not immediately depend on PEX5 removal. The second is directly coupled, in which cargo translocation only occurs when its PEX5 is removed from the peroxisomal membrane. The third, novel, model is cooperatively coupled and requires two PEX5 on a given importomer for cargo translocation — one PEX5 with associated cargo and one with ubiquitin. We measure both the PEX5 and the ubiquitin levels on the peroxisomes as we vary the matrix protein cargo addition rate into the cytosol. We find that both uncoupled and directly coupled translocation behave identically with respect to PEX5 and ubiquitin, and the peroxisomal ubiquitin signal increases as the matrix protein traffic increases. In contrast, cooperatively coupled translocation behaves dramatically differently, with a ubiquitin signal that decreases with increasing matrix protein traffic. Recent work has shown that ubiquitin on mammalian peroxisome membranes can lead to selective degradation by autophagy, or ‘pexophagy.’ Therefore, the high ubiquitin level for low matrix cargo traffic with cooperatively coupled protein translocation could be used as a disuse signal to mediate pexophagy. This mechanism may be one way that cells could regulate peroxisome numbers. Peroxisomes are small organelles that must continually import matrix proteins to contribute to cholesterol and bile acid synthesis, among other important functions. Cargo matrix proteins are shuttled to the peroxisomal membrane, but the only source of energy that has been identified to translocate the cargo into the peroxisome is consumed during the removal of the shuttle protein. Ubiquitin is used to recycle peroxisomal shuttle proteins, but is more generally used in cells to signal degradation of damaged or unneeded cellular components. How shuttle removal and cargo translocation are coupled energetically has been difficult to determine directly, so we investigate how different models of coupling would affect the measurable levels of ubiquitin on mammalian peroxisomes. We find that for the simplest models of coupling, ubiquitin levels decrease as cargo levels decrease. Conversely, for a novel cooperative model of coupling we find that ubiquitin levels increase as cargo levels decrease. This effect could allow the cell to degrade peroxisomes when they are not used, or to avoid degrading peroxisomes as cargo levels increase. Regardless of which model is found to be right, we have shown that ubiquitination levels of peroxisomes should respond to the changing traffic of matrix proteins into peroxisomes.
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Affiliation(s)
- Aidan I. Brown
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Peter K. Kim
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
- Cell Biology Program, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Andrew D. Rutenberg
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, Canada
- * E-mail:
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29
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Platta HW, Hagen S, Reidick C, Erdmann R. The peroxisomal receptor dislocation pathway: to the exportomer and beyond. Biochimie 2013; 98:16-28. [PMID: 24345375 DOI: 10.1016/j.biochi.2013.12.009] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Accepted: 12/05/2013] [Indexed: 12/29/2022]
Abstract
The biogenesis of peroxisomes is an ubiquitin-dependent process. In particular, the import of matrix proteins into the peroxisomal lumen requires the modification of import receptors with ubiquitin. The matrix proteins are synthesized on free polyribosomes in the cytosol and are recognized by import receptors via a peroxisomal targeting sequence (PTS). Subsequent to the transport of the receptor/cargo-complex to the peroxisomal membrane and the release of the cargo into the peroxisomal lumen, the PTS-receptors are exported back to the cytosol for further rounds of matrix protein import. The exportomer represents the molecular machinery required for the retrotranslocation of the PTS-receptors. It comprises enzymes for the ubiquitination as well as for the ATP-dependent extraction of the PTS-receptors from the peroxisomal membrane. Furthermore, recent evidence indicates a mechanistic interconnection of the ATP-dependent removal of the PTS-receptors with the translocation of the matrix protein into the organellar lumen. Interestingly, the components of the peroxisomal exportomer seem also to be involved in cellular tasks that are distinct from the ubiquitination and dislocation of the peroxisomal PTS-receptors. This includes work that indicates a central function of this machinery in the export of peroxisomal matrix proteins in plants, while a subset of exportomer components is involved in the meiocyte formation in some fungi, the peroxisome-chloroplast contact during photorespiration in plants and possibly even the selective degradation of peroxisomes via pexophagy. In this review, we want to discuss the central role of the exportomer during matrix protein import, but also highlight distinct roles of exportomer constituents in additional cellular processes. This article is part of a Special Issue entitled: Peroxisomes: biogenesis, functions and diseases.
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Affiliation(s)
- Harald W Platta
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, Universitätsstr. 150, D-44780 Bochum, Germany.
| | - Stefanie Hagen
- Systembiochemie, Ruhr-Universität Bochum, Universitätsstr. 150, D-44780 Bochum, Germany
| | - Christina Reidick
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, Universitätsstr. 150, D-44780 Bochum, Germany
| | - Ralf Erdmann
- Systembiochemie, Ruhr-Universität Bochum, Universitätsstr. 150, D-44780 Bochum, Germany.
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30
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Neuhaus A, Kooshapur H, Wolf J, Meyer NH, Madl T, Saidowsky J, Hambruch E, Lazam A, Jung M, Sattler M, Schliebs W, Erdmann R. A novel Pex14 protein-interacting site of human Pex5 is critical for matrix protein import into peroxisomes. J Biol Chem 2013; 289:437-48. [PMID: 24235149 DOI: 10.1074/jbc.m113.499707] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protein import into peroxisomes relies on the import receptor Pex5, which recognizes proteins with a peroxisomal targeting signal 1 (PTS1) in the cytosol and directs them to a docking complex at the peroxisomal membrane. Receptor-cargo docking occurs at the membrane-associated protein Pex14. In human cells, this interaction is mediated by seven conserved diaromatic penta-peptide motifs (WXXX(F/Y) motifs) in the N-terminal half of Pex5 and the N-terminal domain of Pex14. A systematic screening of a Pex5 peptide library by ligand blot analysis revealed a novel Pex5-Pex14 interaction site of Pex5. The novel motif composes the sequence LVAEF with the evolutionarily conserved consensus sequence LVXEF. Replacement of the amino acid LVAEF sequence by alanines strongly affects matrix protein import into peroxisomes in vivo. The NMR structure of a complex of Pex5-(57-71) with the Pex14-N-terminal domain showed that the novel motif binds in a similar α-helical orientation as the WXXX(F/Y) motif but that the tryptophan pocket is now occupied by a leucine residue. Surface plasmon resonance analyses revealed 33 times faster dissociation rates for the LVXEF ligand when compared with a WXXX(F/Y) motif. Surprisingly, substitution of the novel motif with the higher affinity WXXX(F/Y) motif impairs protein import into peroxisomes. These data indicate that the distinct kinetic properties of the novel Pex14-binding site in Pex5 are important for processing of the peroxisomal targeting signal 1 receptor at the peroxisomal membrane. The novel Pex14-binding site may represent the initial tethering site of Pex5 from which the cargo-loaded receptor is further processed in a sequential manner.
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Affiliation(s)
- Alexander Neuhaus
- From the Institut für Physiologische Chemie, Abteilung Systembiochemie, Ruhr-Universität Bochum, D-44780 Bochum
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31
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Apanasets O, Grou CP, Van Veldhoven PP, Brees C, Wang B, Nordgren M, Dodt G, Azevedo JE, Fransen M. PEX5, the shuttling import receptor for peroxisomal matrix proteins, is a redox-sensitive protein. Traffic 2013; 15:94-103. [PMID: 24118911 DOI: 10.1111/tra.12129] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 10/03/2013] [Accepted: 10/07/2013] [Indexed: 01/11/2023]
Abstract
Peroxisome maintenance depends on the import of nuclear-encoded proteins from the cytosol. The vast majority of these proteins is destined for the peroxisomal lumen and contains a C-terminal peroxisomal targeting signal, called PTS1. This targeting signal is recognized in the cytosol by the receptor PEX5. After docking at the peroxisomal membrane and release of the cargo into the organelle matrix, PEX5 is recycled to the cytosol through a process requiring monoubiquitination of an N-terminal, cytosolically exposed cysteine residue (Cys11 in the human protein). At present, the reason why a cysteine, and not a lysine residue, is the target of ubiquitination remains unclear. Here, we provide evidence that PTS1 protein import into human fibroblasts is a redox-sensitive process. We also demonstrate that Cys11 in human PEX5 functions as a redox switch that regulates PEX5 activity in response to intracellular oxidative stress. Finally, we show that exposure of human PEX5 to oxidized glutathione results in a ubiquitination-deficient PEX5 molecule, and that substitution of Cys11 by a lysine can counteract this effect. In summary, these findings reveal that the activity of PEX5, and hence PTS1 import, is controlled by the redox state of the cytosol. The potential physiological implications of these findings are discussed.
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Affiliation(s)
- Oksana Apanasets
- Laboratory of Lipid Biochemistry and Protein Interactions, Department of Cellular and Molecular Medicine, KU, Leuven, Belgium
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32
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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] [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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33
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Vamecq J, Cherkaoui-Malki M, Andreoletti P, Latruffe N. The human peroxisome in health and disease: the story of an oddity becoming a vital organelle. Biochimie 2013; 98:4-15. [PMID: 24075875 DOI: 10.1016/j.biochi.2013.09.019] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Accepted: 09/18/2013] [Indexed: 12/18/2022]
Abstract
Since the first report by Rhodin in 1954, our knowledge on mammalian microbodies/peroxisomes has known several periods. An initial two decades period (1954-1973) has contributed to the biochemical individualisation of peroxisomes as a new class of subcellular organelles (de Duve, 1965). The corresponding research period failed to define a clear role of mammalian peroxisomes in vital functions and intermediary metabolism, explaining why feeling that peroxisomes might be in the human cell oddities has prevailed during several decades. The period standing from 1973 to nowadays has progressively removed this cell oddity view of peroxisomes by highlighting vital function and metabolic role of peroxisomes in health and disease along with genetic and metabolic regulation of peroxisomal protein content, organelle envelope formation and protein signal targeting mechanisms. Research on peroxisomes and their response to various drugs and metabolites, dietary and physiological conditions has also played a key role in the discovery of peroxisome proliferator activated receptors (PPARs) belonging to the nuclear hormone receptor superfamily and for which impact in science and medicine goes now by far beyond that of the peroxisomes.
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Affiliation(s)
- Joseph Vamecq
- INSERM, Laboratory of Biochemistry and Molecular Biology, Hormonology-Metabolism-Nutrition-Oncology, Centre of Biology and Pathology (CBP), CHU Lille, France.
| | - Mustapha Cherkaoui-Malki
- Laboratory of Biochemistry of Peroxisome, Inflammation & Lipids Metabolism (BioPeroxIL-EA7270), University of Burgundy, 21000 Dijon, France
| | - Pierre Andreoletti
- Laboratory of Biochemistry of Peroxisome, Inflammation & Lipids Metabolism (BioPeroxIL-EA7270), University of Burgundy, 21000 Dijon, France
| | - Norbert Latruffe
- Laboratory of Biochemistry of Peroxisome, Inflammation & Lipids Metabolism (BioPeroxIL-EA7270), University of Burgundy, 21000 Dijon, France
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34
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Hasan S, Platta HW, Erdmann R. Import of proteins into the peroxisomal matrix. Front Physiol 2013; 4:261. [PMID: 24069002 PMCID: PMC3781343 DOI: 10.3389/fphys.2013.00261] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 09/03/2013] [Indexed: 12/03/2022] Open
Abstract
Peroxisomes constitute a dynamic compartment in all nucleated cells. They fulfill diverse metabolic tasks in response to environmental changes and cellular demands. This adaptation is implemented by modulation of the enzyme content of the organelles, which is accomplished by dynamically operating peroxisomal protein transport machineries. Soluble import receptors recognize their newly synthesized cargo proteins in the cytosol and ferry them to the peroxisomal membrane. Subsequently, the cargo is translocated into the matrix, where the receptor is ubiquitinated and exported back to the cytosol for further rounds of matrix protein import. This review discusses the recent progress in our understanding of the peroxisomal matrix protein import and its regulation by ubiquitination events as well as the current view on the translocation mechanism of folded proteins into peroxisomes. This article is part of a Special Issue entitled: Origin and spatiotemporal dynamics of the peroxisomal endomembrane system.
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Affiliation(s)
- Sohel Hasan
- Systembiochemie, Medizinische Fakultät, Ruhr-Universität Bochum Bochum, Germany
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35
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Peraza-Reyes L, Berteaux-Lecellier V. Peroxisomes and sexual development in fungi. Front Physiol 2013; 4:244. [PMID: 24046747 PMCID: PMC3764329 DOI: 10.3389/fphys.2013.00244] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2013] [Accepted: 08/19/2013] [Indexed: 11/13/2022] Open
Abstract
Peroxisomes are versatile and dynamic organelles that are essential for the development of most eukaryotic organisms. In fungi, many developmental processes, such as sexual development, require the activity of peroxisomes. Sexual reproduction in fungi involves the formation of meiotic-derived sexual spores, often takes place inside multicellular fruiting bodies and requires precise coordination between the differentiation of multiple cell types and the progression of karyogamy and meiosis. Different peroxisomal functions contribute to the orchestration of this complex developmental process. Peroxisomes are required to sustain the formation of fruiting bodies and the maturation and germination of sexual spores. They facilitate the mobilization of reserve compounds via fatty acid β-oxidation and the glyoxylate cycle, allowing the generation of energy and biosynthetic precursors. Additionally, peroxisomes are implicated in the progression of meiotic development. During meiotic development in Podospora anserina, there is a precise modulation of peroxisome assembly and dynamics. This modulation includes changes in peroxisome size, number and localization, and involves a differential activity of the protein-machinery that drives the import of proteins into peroxisomes. Furthermore, karyogamy, entry into meiosis and sorting of meiotic-derived nuclei into sexual spores all require the activity of peroxisomes. These processes rely on different peroxisomal functions and likely depend on different pathways for peroxisome assembly. Indeed, emerging studies support the existence of distinct import channels for peroxisomal proteins that contribute to different developmental stages.
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Affiliation(s)
- Leonardo Peraza-Reyes
- CNRS, Institut de Génétique et Microbiologie, University Paris-Sud, UMR8621 Orsay, France
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36
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Gualdrón-López M, Chevalier N, Van Der Smissen P, Courtoy PJ, Rigden DJ, Michels PAM. Ubiquitination of the glycosomal matrix protein receptor PEX5 in Trypanosoma brucei by PEX4 displays novel features. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:3076-3092. [PMID: 23994617 DOI: 10.1016/j.bbamcr.2013.08.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 08/08/2013] [Accepted: 08/12/2013] [Indexed: 12/12/2022]
Abstract
Trypanosomatids contain peroxisome-like organelles called glycosomes. Peroxisomal biogenesis involves a cytosolic receptor, PEX5, which, after its insertion into the organellar membrane, delivers proteins to the matrix. In yeasts and mammalian cells, transient PEX5 monoubiquitination at the membrane serves as the signal for its retrieval from the organelle for re-use. When its recycling is impaired, PEX5 is polyubiquitinated for proteasomal degradation. Stably monoubiquitinated TbPEX5 was detected in cytosolic fractions of Trypanosoma brucei, indicative for its role as physiological intermediate in receptor recycling. This modification's resistance to dithiothreitol suggests ubiquitin conjugation of a lysine residue. T. brucei PEX4, the functional homologue of the ubiquitin-conjugating (UBC) enzyme responsible for PEX5 monoubiquitination in yeast, was identified. It is associated with the cytosolic face of the glycosomal membrane, probably anchored by an identified putative TbPEX22. The involvement of TbPEX4 in TbPEX5 ubiquitination was demonstrated using procyclic ∆PEX4 trypanosomes. Surprisingly, glycosomal matrix protein import was only mildly affected in this mutant. Since other UBC homologues were upregulated, it might be possible that these have partially rescued PEX4's function in PEX5 ubiquitination. In addition, the altered expression of UBCs, notably of candidates involved in cell-cycle control, could be responsible for observed morphological and motility defects of the ∆PEX4 mutant.
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Affiliation(s)
- Melisa Gualdrón-López
- Research Unit for Tropical Diseases, de Duve Institute, and Laboratory of Biochemistry, Université catholique de Louvain, Avenue Hippocrate 74, B-1200 Brussels, Belgium
| | - Nathalie Chevalier
- Research Unit for Tropical Diseases, de Duve Institute, and Laboratory of Biochemistry, Université catholique de Louvain, Avenue Hippocrate 74, B-1200 Brussels, Belgium
| | - Patrick Van Der Smissen
- Cell Biology Unit, de Duve Institute, Université catholique de Louvain, Avenue Hippocrate 75, B-1200 Brussels, Belgium
| | - Pierre J Courtoy
- Cell Biology Unit, de Duve Institute, Université catholique de Louvain, Avenue Hippocrate 75, B-1200 Brussels, Belgium
| | - Daniel J Rigden
- Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK
| | - Paul A M Michels
- Research Unit for Tropical Diseases, de Duve Institute, and Laboratory of Biochemistry, Université catholique de Louvain, Avenue Hippocrate 74, B-1200 Brussels, Belgium.
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37
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Francisco T, Rodrigues TA, Freitas MO, Grou CP, Carvalho AF, Sá-Miranda C, Pinto MP, Azevedo JE. A cargo-centered perspective on the PEX5 receptor-mediated peroxisomal protein import pathway. J Biol Chem 2013; 288:29151-9. [PMID: 23963456 DOI: 10.1074/jbc.m113.487140] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Peroxisomal matrix proteins are synthesized on cytosolic ribosomes and post-translationally targeted to the organelle by PEX5, the peroxisomal shuttling receptor. The pathway followed by PEX5 during this process is known with reasonable detail. After recognizing cargo proteins in the cytosol, the receptor interacts with the peroxisomal docking/translocation machinery, where it gets inserted; PEX5 is then monoubiquitinated, extracted back to the cytosol and, finally, deubiquitinated. However, despite this information, the exact step of this pathway where cargo proteins are translocated across the organelle membrane is still ill-defined. In this work, we used an in vitro import system to characterize the translocation mechanism of a matrix protein possessing a type 1 targeting signal. Our results suggest that translocation of proteins across the organelle membrane occurs downstream of a reversible docking step and upstream of the first cytosolic ATP-dependent step (i.e. before ubiquitination of PEX5), concomitantly with the insertion of the receptor into the docking/translocation machinery.
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38
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Francisco T, Rodrigues TA, Pinto MP, Carvalho AF, Azevedo JE, Grou CP. Ubiquitin in the peroxisomal protein import pathway. Biochimie 2013; 98:29-35. [PMID: 23954799 DOI: 10.1016/j.biochi.2013.08.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2013] [Accepted: 08/05/2013] [Indexed: 10/26/2022]
Abstract
PEX5 is the shuttling receptor for newly synthesized peroxisomal matrix proteins. Alone, or with the help of an adaptor protein, this receptor binds peroxisomal matrix proteins in the cytosol and transports them to the peroxisomal membrane docking/translocation module (DTM). The interaction between cargo-loaded PEX5 and the DTM ultimately results in its insertion into the DTM with the concomitant translocation of the cargo protein across the organelle membrane. PEX5 is not consumed in this event; rather it is dislocated back into the cytosol so that it can promote additional rounds of protein transportation. Remarkably, the data collected in recent years indicate that dislocation is preceded by monoubiquitination of PEX5 at a conserved cysteine residue. This mandatory modification is not the only type of ubiquitination occurring at the DTM. Indeed, several findings suggest that defective receptors jamming the DTM are polyubiquitinated and targeted to the proteasome for degradation.
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Affiliation(s)
- Tânia Francisco
- Organelle Biogenesis and Function Group, Instituto de Biologia Celular e Molecular (IBMC), Universidade do Porto, R. do Campo Alegre, 823, 4150-180 Porto, Portugal; Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, R. de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Tony A Rodrigues
- Organelle Biogenesis and Function Group, Instituto de Biologia Celular e Molecular (IBMC), Universidade do Porto, R. do Campo Alegre, 823, 4150-180 Porto, Portugal; Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, R. de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Manuel P Pinto
- Organelle Biogenesis and Function Group, Instituto de Biologia Celular e Molecular (IBMC), Universidade do Porto, R. do Campo Alegre, 823, 4150-180 Porto, Portugal
| | - Andreia F Carvalho
- Organelle Biogenesis and Function Group, Instituto de Biologia Celular e Molecular (IBMC), Universidade do Porto, R. do Campo Alegre, 823, 4150-180 Porto, Portugal
| | - Jorge E Azevedo
- Organelle Biogenesis and Function Group, Instituto de Biologia Celular e Molecular (IBMC), Universidade do Porto, R. do Campo Alegre, 823, 4150-180 Porto, Portugal; Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, R. de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
| | - Cláudia P Grou
- Organelle Biogenesis and Function Group, Instituto de Biologia Celular e Molecular (IBMC), Universidade do Porto, R. do Campo Alegre, 823, 4150-180 Porto, Portugal.
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Nordgren M, Wang B, Apanasets O, Fransen M. Peroxisome degradation in mammals: mechanisms of action, recent advances, and perspectives. Front Physiol 2013; 4:145. [PMID: 23785334 PMCID: PMC3682127 DOI: 10.3389/fphys.2013.00145] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 05/30/2013] [Indexed: 12/18/2022] Open
Abstract
Peroxisomes are remarkably dynamic organelles that participate in a diverse array of cellular processes, including the metabolism of lipids and reactive oxygen species. In order to regulate peroxisome function in response to changing nutritional and environmental stimuli, new organelles need to be formed and superfluous and dysfunctional organelles have to be selectively removed. Disturbances in any of these processes have been associated with the etiology and progression of various congenital neurodegenerative and age-related human disorders. The aim of this review is to critically explore our current knowledge of how peroxisomes are degraded in mammalian cells and how defects in this process may contribute to human disease. Some of the key issues highlighted include the current concepts of peroxisome removal, the peroxisome quality control mechanisms, the initial triggers for peroxisome degradation, the factors for dysfunctional peroxisome recognition, and the regulation of peroxisome homeostasis. We also dissect the functional and mechanistic relationship between different forms of selective organelle degradation and consider how lysosomal dysfunction may lead to defects in peroxisome turnover. In addition, we draw lessons from studies on other organisms and extrapolate this knowledge to mammals. Finally, we discuss the potential pathological implications of dysfunctional peroxisome degradation for human health.
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Affiliation(s)
- Marcus Nordgren
- Laboratory of Lipid Biochemistry and Protein Interactions, Department of Cellular and Molecular Medicine, Katholieke Universiteit Leuven Leuven, Vlaams-Brabant, Belgium
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Gualdrón-López M, Michels PA. Processing of the glycosomal matrix-protein import receptor PEX5 of Trypanosoma brucei. Biochem Biophys Res Commun 2013; 431:98-103. [DOI: 10.1016/j.bbrc.2012.12.075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Accepted: 12/10/2012] [Indexed: 10/27/2022]
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