1
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Arie M, Matzov D, Karmona R, Szenkier N, Stanhill A, Navon A. A non-symmetrical p97 conformation initiates a multistep recruitment of Ufd1/Npl4. iScience 2024; 27:110061. [PMID: 38947518 PMCID: PMC11214410 DOI: 10.1016/j.isci.2024.110061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2024] [Revised: 04/10/2024] [Accepted: 05/17/2024] [Indexed: 07/02/2024] Open
Abstract
In vitro experiments and cryo-EM structures of p97 and its cofactor, Ufd1/Npl4 (UN), elucidated substrate processing. Yet, the structural transitions and the related ATPase cycle upon UN binding remain unresolved. We captured two discrete conformations: One in which D1 protomers are ATP bound, while the D2 subunits are in the ADP state, presumably required for substrate engagement with the D2 pore; and a heterologous nucleotide state within the D1 ring in which only two NTDs are in the "up" ATP state that favors UN binding. Further analysis suggests that initially, UN binds p97's non-symmetrical conformation, this association promotes a structural transition upon which five NTDs shift to an "up" state and are poised to bind ATP. The UBXL domain of Npl4 was captured bound to an NTD in the ADP state, demonstrating a conformation that may provide directionality to incoming substrate and introduce the flexibility needed for substrate processing.
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Affiliation(s)
- Michal Arie
- Department of Immunology and Regenerative Biology, The Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Donna Matzov
- Department of Chemical and Structural Biology, The Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Rotem Karmona
- Department of Immunology and Regenerative Biology, The Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Natalia Szenkier
- Department of Immunology and Regenerative Biology, The Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Ariel Stanhill
- Department of Natural Sciences, The Open University of Israel, Raanana 4353701, Israel
| | - Ami Navon
- Department of Immunology and Regenerative Biology, The Weizmann Institute of Science, Rehovot 7610001, Israel
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2
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Swan RL, Cowell IG, Austin CA. Mechanisms to repair stalled Topoisomerase II-DNA covalent complexes. Mol Pharmacol 2021; 101:24-32. [PMID: 34689119 DOI: 10.1124/molpharm.121.000374] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 10/11/2021] [Indexed: 11/22/2022] Open
Abstract
DNA topoisomerases regulate the topological state of DNA, relaxing DNA supercoils and resolving catenanes and knots that result from biological processes such as transcription and replication. DNA topoisomerase II (TOP2) enzymes achieve this by binding DNA and introducing an enzyme-bridged DNA double-strand break (DSB) where each protomer of the dimeric enzyme is covalently attached to the 5' end of the cleaved DNA via an active site tyrosine phosphodiester linkage. The enzyme then passes a second DNA duplex though the DNA break, before religation and release of the enzyme. However, this activity is potentially hazardous to the cell, as failure to complete religation leads to persistent TOP2 protein-DNA covalent complexes which are cytotoxic. Indeed, this property of topoisomerase has been exploited in cancer therapy in the form of topoisomerase poisons which block the religation stage of the reaction cycle, leading to an accumulation of topoisomerase-DNA adducts. A number of parallel cellular processes have been identified that lead to removal of these covalent TOP2-DNA complexes facilitating repair of the resulting protein-free DSB by standard DNA repair pathways. These pathways presumably arose to repair spontaneous stalled or poisoned TOP2-DNA complexes, but understanding their mechanisms also has implications for cancer therapy, particularly resistance to anti-cancer TOP2 poisons and the genotoxic side effects of these drugs. Here we review recent progress in the understanding of the processing to TOP2 DNA covalent complexes., The basic components and mechanisms plus the additional layer of complexity posed by the post-translational modifications that modulate these pathways. Significance Statement Multiple pathways have been reported for removal and repair of TOP2-DNA covalent complexes to ensure the timely and efficient repair of TOP2-DNA covalent adducts to protect the genome. Post-translational modifications such as ubiquitination and SUMOylation are involved in the regulation of TOP2-DNA complex repair. Small molecule inhibitors of these post translational modifications may help to improve outcomes of TOP2 poison chemotherapy, for example by increasing TOP2 poison cytotoxicity and reducing genotoxicity, but this remains to be determined.
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Affiliation(s)
- Rebecca L Swan
- Biosciences Institute, Newcastle University, United Kingdom
| | - Ian G Cowell
- Institute for Cell and Molecular Biosciences, Newcastle University, United Kingdom
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3
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An Arsenite Relay between PSMD14 and AIRAP Enables Revival of Proteasomal DUB Activity. Biomolecules 2021; 11:biom11091317. [PMID: 34572530 PMCID: PMC8465394 DOI: 10.3390/biom11091317] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 09/01/2021] [Accepted: 09/03/2021] [Indexed: 01/21/2023] Open
Abstract
Maintaining 26S proteasome activity under diverse physiological conditions is a fundamental requirement in order to maintain cellular proteostasis. Several quantitative and qualitative mechanisms have evolved to ensure that ubiquitin–proteasome system (UPS) substrates do not accumulate and lead to promiscuous protein–protein interactions that, in turn, lead to cellular malfunction. In this report, we demonstrate that Arsenite Inducible Regulatory Particle-Associate Protein (AIRAP), previously reported as a proteasomal adaptor required for maintaining proteasomal flux during arsenite exposure, can directly bind arsenite molecules. We further show that arsenite inhibits Psmd14/Rpn11 metalloprotease deubiquitination activity by substituting zinc binding to the MPN/JAMM domain. The proteasomal adaptor AIRAP is able to directly relieve PSMD14/Rpn11 inhibition. A possible metal relay between arsenylated PSMD14/Rpn11 and AIRAP may serve as a cellular mechanism that senses proteasomal inhibition to restore Psmd14/Rpn11 activity.
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4
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Moon SL, Morisaki T, Stasevich TJ, Parker R. Coupling of translation quality control and mRNA targeting to stress granules. J Cell Biol 2021; 219:151851. [PMID: 32520986 PMCID: PMC7401812 DOI: 10.1083/jcb.202004120] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 05/05/2020] [Accepted: 05/06/2020] [Indexed: 02/07/2023] Open
Abstract
Stress granules are dynamic assemblies of proteins and nontranslating RNAs that form when translation is inhibited in response to diverse stresses. Defects in ubiquitin–proteasome system factors including valosin-containing protein (VCP) and the proteasome impact the kinetics of stress granule induction and dissolution as well as being implicated in neuropathogenesis. However, the impacts of dysregulated proteostasis on mRNA regulation and stress granules are not well understood. Using single mRNA imaging, we discovered ribosomes stall on some mRNAs during arsenite stress, and the release of transcripts from stalled ribosomes for their partitioning into stress granules requires the activities of VCP, components of the ribosome-associated quality control (RQC) complex, and the proteasome. This is an unexpected contribution of the RQC system in releasing mRNAs from translation under stress, thus identifying a new type of stress-activated RQC (saRQC) distinct from canonical RQC pathways in mRNA substrates, cellular context, and mRNA fate.
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Affiliation(s)
- Stephanie L Moon
- Department of Human Genetics, University of Michigan, Ann Arbor, MI.,Center for RNA Biomedicine, University of Michigan, Ann Arbor, MI
| | - Tatsuya Morisaki
- Department of Biochemistry, Colorado State University, Fort Collins, CO
| | - Timothy J Stasevich
- Department of Biochemistry, Colorado State University, Fort Collins, CO.,World Research Hub Initiative, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Roy Parker
- Department of Biochemistry, University of Colorado, Boulder, CO.,Howard Hughes Medical Institute, Chevy Chase, MD
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5
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Yang Q, Yao Y, Li K, Jiao L, Zhu J, Ni C, Li M, Dou QP, Yang H. An Updated Review of Disulfiram: Molecular Targets and Strategies for Cancer Treatment. Curr Pharm Des 2020; 25:3248-3256. [PMID: 31419930 DOI: 10.2174/1381612825666190816233755] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 08/06/2019] [Indexed: 12/31/2022]
Abstract
Repurposing already approved drugs as new anticancer agents is a promising strategy considering the advantages such as low costs, low risks and less time-consumption. Disulfiram (DSF), as the first drug for antialcoholism, was approved by the U.S. Food and Drug Administration (FDA) over 60 years ago. Increasing evidence indicates that DSF has great potential for the treatment of various human cancers. Several mechanisms and targets of DSF related to cancer therapy have been proposed, including the inhibition of ubiquitin-proteasome system (UPS), cancer cell stemness and cancer metastasis, and alteration of the intracellular reactive oxygen species (ROS). This article provides a brief review about the history of the use of DSF in humans and its molecular mechanisms and targets of anticancer therapy, describes DSF delivery strategies for cancer treatment, summarizes completed and ongoing cancer clinical trials involving DSF, and offers strategies to better use DSF in cancer therapies.
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Affiliation(s)
- Qingzhu Yang
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Yao Yao
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Kai Li
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Lin Jiao
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Jiazhen Zhu
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Cheng Ni
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Mengmeng Li
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Q Ping Dou
- Departments of Oncology, Pharmacology and Pathology, Barbara Ann Karmanos Cancer Institute, School of Medicine, Wayne State University, Detroit, United States
| | - Huanjie Yang
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
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6
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Nowakowska-Gołacka J, Sominka H, Sowa-Rogozińska N, Słomińska-Wojewódzka M. Toxins Utilize the Endoplasmic Reticulum-Associated Protein Degradation Pathway in Their Intoxication Process. Int J Mol Sci 2019; 20:E1307. [PMID: 30875878 PMCID: PMC6471375 DOI: 10.3390/ijms20061307] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 03/08/2019] [Accepted: 03/10/2019] [Indexed: 12/25/2022] Open
Abstract
Several bacterial and plant AB-toxins are delivered by retrograde vesicular transport to the endoplasmic reticulum (ER), where the enzymatically active A subunit is disassembled from the holotoxin and transported to the cytosol. In this process, toxins subvert the ER-associated degradation (ERAD) pathway. ERAD is an important part of cellular regulatory mechanism that targets misfolded proteins to the ER channels, prior to their retrotranslocation to the cytosol, ubiquitination and subsequent degradation by a protein-degrading complex, the proteasome. In this article, we present an overview of current understanding of the ERAD-dependent transport of AB-toxins to the cytosol. We describe important components of ERAD and discuss their significance for toxin transport. Toxin recognition and disassembly in the ER, transport through ER translocons and finally cytosolic events that instead of overall proteasomal degradation provide proper folding and cytotoxic activity of AB-toxins are discussed as well. We also comment on recent reports presenting medical applications for toxin transport through the ER channels.
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Affiliation(s)
- Jowita Nowakowska-Gołacka
- Department of Medical Biology and Genetics, Faculty of Biology, University of Gdańsk, Wita Stwosza 59, 80-308 Gdańsk, Poland.
| | - Hanna Sominka
- Department of Medical Biology and Genetics, Faculty of Biology, University of Gdańsk, Wita Stwosza 59, 80-308 Gdańsk, Poland.
| | - Natalia Sowa-Rogozińska
- Department of Medical Biology and Genetics, Faculty of Biology, University of Gdańsk, Wita Stwosza 59, 80-308 Gdańsk, Poland.
| | - Monika Słomińska-Wojewódzka
- Department of Medical Biology and Genetics, Faculty of Biology, University of Gdańsk, Wita Stwosza 59, 80-308 Gdańsk, Poland.
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7
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ZFAND1 Recruits p97 and the 26S Proteasome to Promote the Clearance of Arsenite-Induced Stress Granules. Mol Cell 2018; 70:906-919.e7. [PMID: 29804830 DOI: 10.1016/j.molcel.2018.04.021] [Citation(s) in RCA: 101] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 03/28/2018] [Accepted: 04/23/2018] [Indexed: 01/10/2023]
Abstract
Stress granules (SGs) are cytoplasmic assemblies of mRNPs stalled in translation initiation. They are induced by various stress conditions, including exposure to the environmental toxin and carcinogen arsenic. While perturbed SG turnover is linked to the pathogenesis of neurodegenerative diseases, the molecular mechanisms underlying SG formation and turnover are still poorly understood. Here, we show that ZFAND1 is an evolutionarily conserved regulator of SG clearance. ZFAND1 interacts with two key factors of protein degradation, the 26S proteasome and the ubiquitin-selective segregase p97, and recruits them to arsenite-induced SGs. In the absence of ZFAND1, SGs lack the 26S proteasome and p97, accumulate defective ribosomal products, and persist after arsenite removal, indicating their transformation into aberrant, disease-linked SGs. Accordingly, ZFAND1 depletion is epistatic to the expression of pathogenic mutant p97 with respect to SG clearance, suggesting that ZFAND1 function is relevant to the multisystem degenerative disorder IBMPFD/ALS.
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8
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Römisch K. A Case for Sec61 Channel Involvement in ERAD. Trends Biochem Sci 2016; 42:171-179. [PMID: 27932072 DOI: 10.1016/j.tibs.2016.10.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 10/19/2016] [Accepted: 10/20/2016] [Indexed: 11/25/2022]
Abstract
Proteins that misfold in the endoplasmic reticulum (ER) need to be transported back to the cytosol for degradation by proteasomes, a process known as ER-associated degradation (ERAD). The first candidate discussed as a retrograde protein transport conduit was the Sec61 channel which is responsible for secretory protein transport into the ER during biogenesis. The Sec61 channel binds the proteasome 19S regulatory particle which can extract an ERAD substrate from the ER. Nevertheless its role as a general export channel has been dismissed, and Hrd1 and Der1 have been proposed as alternatives. The discovery of export-specific sec61 mutants and of mammalian ERAD substrates whose export is dependent on the 19S regulatory particle suggest that dismissal of a role of Sec61 in export may have been premature.
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Affiliation(s)
- Karin Römisch
- Department of Biology, Naturwissenschaftlich-technische Fakultät 8, Saarland University, 66123 Saarbruecken, Germany.
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9
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McEwan WA. Surveillance for Intracellular Antibody by Cytosolic Fc Receptor TRIM21. Antibodies (Basel) 2016; 5:antib5040021. [PMID: 31558002 PMCID: PMC6698813 DOI: 10.3390/antib5040021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2016] [Revised: 08/01/2016] [Accepted: 08/09/2016] [Indexed: 12/12/2022] Open
Abstract
TRIM21 has emerged as an atypical Fc receptor that is broadly conserved and widely expressed in the cytoplasm of mammalian cells. Viruses that traffic surface-bound antibodies into the cell during infection recruit TRIM21 via a high affinity interaction between Fc and TRIM21 PRYSPRY domain. Following binding of intracellular antibody, TRIM21 acts as both antiviral effector and sensor for innate immune signalling. These activities serve to reduce viral replication by orders of magnitude in vitro and contribute to host survival during in vivo infection. Neutralization occurs rapidly after detection and requires the activity of the ubiquitin-proteasome system. The microbial targets of this arm of intracellular immunity are still being identified: TRIM21 activity has been reported following infection by several non-enveloped viruses and intracellular bacteria. These findings extend the sphere of influence of antibodies to the intracellular domain and have broad implications for immunity. TRIM21 has been implicated in the chronic auto-immune condition systemic lupus erythematosus and is itself an auto-antigen in Sjögren’s syndrome. This review summarises our current understanding of TRIM21’s role as a cytosolic Fc receptor and briefly discusses pathological circumstances where intracellular antibodies have been described, or are hypothesized to occur, and may benefit from further investigations of the role of TRIM21.
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Affiliation(s)
- William A McEwan
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK.
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10
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Foss S, Watkinson R, Sandlie I, James LC, Andersen JT. TRIM21: a cytosolic Fc receptor with broad antibody isotype specificity. Immunol Rev 2016; 268:328-39. [PMID: 26497531 PMCID: PMC4670481 DOI: 10.1111/imr.12363] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Antibodies are key molecules in the fight against infections. Although previously thought to mediate protection solely in the extracellular environment, recent research has revealed that antibody-mediated protection extends to the cytosolic compartment of cells. This postentry viral defense mechanism requires binding of the antibody to a cytosolic Fc receptor named tripartite motif containing 21 (TRIM21). In contrast to other Fc receptors, TRIM21 shows remarkably broad isotype specificity as it does not only bind IgG but also IgM and IgA. When viral pathogens coated with these antibody isotypes enter the cytosol, TRIM21 is rapidly recruited and efficient neutralization occurs before the virus has had the time to replicate. In addition, inflammatory signaling is induced. As such, TRIM21 acts as a cytosolic sensor that engages antibodies that have failed to protect against infection in the extracellular environment. Here, we summarize our current understanding of how TRIM21 orchestrates humoral immunity in the cytosolic environment.
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Affiliation(s)
- Stian Foss
- Centre for Immune Regulation (CIR) and Department of Biosciences, University of Oslo, Oslo, Norway.,CIR and Department of Immunology, Oslo University Hospital Rikshospitalet and University of Oslo, Oslo, Norway
| | - Ruth Watkinson
- Protein and Nucleic Acid Chemistry Division, Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Inger Sandlie
- Centre for Immune Regulation (CIR) and Department of Biosciences, University of Oslo, Oslo, Norway.,CIR and Department of Immunology, Oslo University Hospital Rikshospitalet and University of Oslo, Oslo, Norway
| | - Leo C James
- Protein and Nucleic Acid Chemistry Division, Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Jan Terje Andersen
- CIR and Department of Immunology, Oslo University Hospital Rikshospitalet and University of Oslo, Oslo, Norway
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11
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Braunstein I, Zach L, Allan S, Kalies KU, Stanhill A. Proteasomal degradation of preemptive quality control (pQC) substrates is mediated by an AIRAPL-p97 complex. Mol Biol Cell 2015; 26:3719-27. [PMID: 26337389 PMCID: PMC4626058 DOI: 10.1091/mbc.e15-02-0085] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 08/27/2015] [Indexed: 12/20/2022] Open
Abstract
The preemptive quality control (pQC) pathway participates in the unfolded protein response regulating ER homeostasis, yet many components are not known. The role of p97 and its adaptor, AIRAPL, in proteasomal processing of pQC substrates is shown, and an insulin-processing mutant (R6C) is identified as a pQC substrate. The initial folding of secreted proteins occurs in the ER lumen, which contains specific chaperones and where posttranslational modifications may occur. Therefore lack of translocation, regardless of entry route or protein identity, is a highly toxic event, as the newly synthesized polypeptide is misfolded and can promiscuously interact with cytosolic factors. Mislocalized proteins bearing a signal sequence that did not successfully translocate through the translocon complex are subjected to a preemptive quality control (pQC) pathway and are degraded by the ubiquitin-proteasome system (UPS). In contrast to UPS-mediated, ER-associated degradation, few components involved in pQC have been identified. Here we demonstrate that on specific translocation inhibition, a p97–AIRAPL complex directly binds and regulates the efficient processing of polyubiquitinated pQC substrates by the UPS. We also demonstrate p97’s role in pQC processing of preproinsulin in cases of naturally occurring mutations within the signal sequence of insulin.
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Affiliation(s)
- Ilana Braunstein
- Department of Biochemistry, Rappaport Family Institute for Research in the Medical Sciences, Technion-Israel Institute of Technology, Haifa 31096, Israel
| | - Lolita Zach
- Department of Biochemistry, Rappaport Family Institute for Research in the Medical Sciences, Technion-Israel Institute of Technology, Haifa 31096, Israel
| | - Susanne Allan
- Centre for Structural and Cell Biology in Medicine, University of Lübeck, 23538 Lübeck, Germany
| | - Kai-Uwe Kalies
- Centre for Structural and Cell Biology in Medicine, University of Lübeck, 23538 Lübeck, Germany
| | - Ariel Stanhill
- Department of Biochemistry, Rappaport Family Institute for Research in the Medical Sciences, Technion-Israel Institute of Technology, Haifa 31096, Israel
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12
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Clemen CS, Marko M, Strucksberg KH, Behrens J, Wittig I, Gärtner L, Winter L, Chevessier F, Matthias J, Türk M, Tangavelou K, Schütz J, Arhzaouy K, Klopffleisch K, Hanisch FG, Rottbauer W, Blümcke I, Just S, Eichinger L, Hofmann A, Schröder R. VCP and PSMF1: Antagonistic regulators of proteasome activity. Biochem Biophys Res Commun 2015; 463:1210-7. [DOI: 10.1016/j.bbrc.2015.06.086] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 06/12/2015] [Indexed: 11/25/2022]
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13
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Leznicki P, Korac-Prlic J, Kliza K, Husnjak K, Nyathi Y, Dikic I, High S. Binding of SGTA to Rpn13 selectively modulates protein quality control. J Cell Sci 2015; 128:3187-96. [PMID: 26169395 PMCID: PMC4582187 DOI: 10.1242/jcs.165209] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 07/03/2015] [Indexed: 12/16/2022] Open
Abstract
Rpn13 is an intrinsic ubiquitin receptor of the 26S proteasome regulatory subunit that facilitates substrate capture prior to degradation. Here we show that the C-terminal region of Rpn13 binds to the tetratricopeptide repeat (TPR) domain of SGTA, a cytosolic factor implicated in the quality control of mislocalised membrane proteins (MLPs). The overexpression of SGTA results in a substantial increase in steady-state MLP levels, consistent with an effect on proteasomal degradation. However, this effect is strongly dependent upon the interaction of SGTA with the proteasomal component Rpn13. Hence, overexpression of the SGTA-binding region of Rpn13 or point mutations within the SGTA TPR domain both inhibit SGTA binding to the proteasome and substantially reduce MLP levels. These findings suggest that SGTA can regulate the access of MLPs to the proteolytic core of the proteasome, implying that a protein quality control cycle that involves SGTA and the BAG6 complex can operate at the 19S regulatory particle. We speculate that the binding of SGTA to Rpn13 enables specific polypeptides to escape proteasomal degradation and/or selectively modulates substrate degradation. Highlighted Article: Binding of SGTA to the proteasome delays substrate degradation, thereby providing a mechanism for potentially viable proteins to be rescued for reuse.
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Affiliation(s)
- Pawel Leznicki
- Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Jelena Korac-Prlic
- Department of Immunology and Medical Genetics, School of Medicine, University of Split, Soltanska 2, Split 21000, Croatia
| | - Katarzyna Kliza
- Institute of Biochemistry II, School of Medicine, Goethe University, Theodor-Stern-Kai 7, Frankfurt (Main) 60590, Germany
| | - Koraljka Husnjak
- Institute of Biochemistry II, School of Medicine, Goethe University, Theodor-Stern-Kai 7, Frankfurt (Main) 60590, Germany
| | - Yvonne Nyathi
- Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Ivan Dikic
- Department of Immunology and Medical Genetics, School of Medicine, University of Split, Soltanska 2, Split 21000, Croatia Institute of Biochemistry II, School of Medicine, Goethe University, Theodor-Stern-Kai 7, Frankfurt (Main) 60590, Germany Buchmann Institute for Molecular Life Sciences, School of Medicine, Goethe University, Theodor-Stern-Kai 7, Frankfurt (Main) 60590, Germany
| | - Stephen High
- Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, UK
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14
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Valosin-containing protein (VCP/p97) is capable of unfolding polyubiquitinated proteins through its ATPase domains. Biochem Biophys Res Commun 2015; 463:453-7. [PMID: 26043696 DOI: 10.1016/j.bbrc.2015.05.111] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 05/29/2015] [Indexed: 11/21/2022]
Abstract
Valosin-containing protein (VCP or p97) is required for the proteasomal degradation of polyubiquitinated proteins. However, the molecular mechanism for VCP to process the polyubiquitinated proteins remains unclear. Here, we show that VCP can unfold polyubiquitinated proteins. It preferably unfolds the pentaubiquitin-over monoubiquin-conjugated dihydrofolate reductase (Ub5-DHFR or Ub-DHFR) in a dose dependent manner. In addition, the unfolding activity of VCP does not depend on its ATPase activity, on the contrary, ATP and its non-hydrolysable analogs suppress the unfolding of Ub5-DHFR. The structural and functional analysis showed that either D1 or D2 domain of VCP is sufficient to carry out this unfolding activity. The structure of the substrates also affects its unfolding by VCP. VCP is unable to unfold Ub5-DHFR in a tight structure when it binds with methotrexate, a folate analog with high affinity to DHFR. Thus, these results support that VCP is capable of unfolding polyubiquitinated proteins and suggest that VCP may facilitate the proteasomal degradation of polyubiquitinated proteins through its unfolding activity.
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15
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Kaiser ML, Römisch K. Proteasome 19S RP binding to the Sec61 channel plays a key role in ERAD. PLoS One 2015; 10:e0117260. [PMID: 25658429 PMCID: PMC4319758 DOI: 10.1371/journal.pone.0117260] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2014] [Accepted: 12/20/2014] [Indexed: 11/24/2022] Open
Abstract
Import of secretory proteins into the Endoplasmic Reticulum (ER) is an established function of the Sec61 channel. The contribution of the Sec61 channel to export of misfolded proteins from the ER for degradation by proteasomes is still controversial, but the proteasome 19S regulatory particle (RP) is necessary and sufficient for extraction of specific misfolded proteins from the ER, and binds directly to the Sec61 channel. In this work we have identified an import-competent sec61 mutant, S353C, carrying a point mutation in ER-lumenal loop 7 which reduces affinity of the cytoplasmic face of the Sec61 channel for the 19S RP. This indicates that the interaction between the 19S RP and the Sec61 channel is dependent on conformational changes in Sec61p hinging on loop 7. The sec61-S353C mutant had no measurable ER import defects and did not cause ER stress in intact cells, but reduced ER-export of a 19S RP-dependent misfolded protein when proteasomes were limiting in a cell-free assay. Our data suggest that the interaction between the 19S RP and the Sec61 channel is essential for the export of specific substrates from the ER to the cytosol for proteasomal degradation.
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Affiliation(s)
- Marie-Luise Kaiser
- Department of Microbiology, Faculty of Natural Sciences and Technology VIII, Saarland University, 66123, Saarbrücken, Germany
| | - Karin Römisch
- Department of Microbiology, Faculty of Natural Sciences and Technology VIII, Saarland University, 66123, Saarbrücken, Germany
- * E-mail:
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16
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McEwan WA, James LC. TRIM21-Dependent Intracellular Antibody Neutralization of Virus Infection. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 129:167-87. [DOI: 10.1016/bs.pmbts.2014.10.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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17
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Piterman R, Braunstein I, Isakov E, Ziv T, Navon A, Cohen S, Stanhill A. VWA domain of S5a restricts the ability to bind ubiquitin and Ubl to the 26S proteasome. Mol Biol Cell 2014; 25:3988-98. [PMID: 25318673 PMCID: PMC4263443 DOI: 10.1091/mbc.e13-11-0697] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The only stoichiometric proteasomal subunit found to reside outside the proteasome is the ubiquitin receptor S5a. S5a-dependent binding of substrates and shuttle factors is restricted to occur only on the proteasome, thus increasing efficiency of substrate degradation by the 26S proteasome. The 26S proteasome recognizes a vast number of ubiquitin-dependent degradation signals linked to various substrates. This recognition is mediated mainly by the stoichiometric proteasomal resident ubiquitin receptors S5a and Rpn13, which harbor ubiquitin-binding domains. Regulatory steps in substrate binding, processing, and subsequent downstream proteolytic events by these receptors are poorly understood. Here we demonstrate that mammalian S5a is present in proteasome-bound and free states. S5a is required for efficient proteasomal degradation of polyubiquitinated substrates and the recruitment of ubiquitin-like (Ubl) harboring proteins; however, S5a-mediated ubiquitin and Ubl binding occurs only on the proteasome itself. We identify the VWA domain of S5a as a domain that limits ubiquitin and Ubl binding to occur only upon proteasomal association. Multiubiquitination events within the VWA domain can further regulate S5a association. Our results provide a molecular explanation to how ubiquitin and Ubl binding to S5a is restricted to the 26S proteasome.
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Affiliation(s)
- Ravit Piterman
- Department of Biochemistry, Rappaport Family Institute for Research in the Medical Sciences, Technion-Israel Institute of Technology, Haifa 31096, Israel
| | - Ilana Braunstein
- Department of Biochemistry, Rappaport Family Institute for Research in the Medical Sciences, Technion-Israel Institute of Technology, Haifa 31096, Israel
| | - Elada Isakov
- Department of Biochemistry, Rappaport Family Institute for Research in the Medical Sciences, Technion-Israel Institute of Technology, Haifa 31096, Israel
| | - Tamar Ziv
- Smoler Proteomics Center, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Ami Navon
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Shenhav Cohen
- Department of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Ariel Stanhill
- Department of Biochemistry, Rappaport Family Institute for Research in the Medical Sciences, Technion-Israel Institute of Technology, Haifa 31096, Israel
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18
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Christianson JC, Ye Y. Cleaning up in the endoplasmic reticulum: ubiquitin in charge. Nat Struct Mol Biol 2014; 21:325-35. [PMID: 24699081 DOI: 10.1038/nsmb.2793] [Citation(s) in RCA: 290] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2013] [Accepted: 02/10/2014] [Indexed: 12/18/2022]
Abstract
The eukaryotic endoplasmic reticulum (ER) maintains protein homeostasis by eliminating unwanted proteins through the evolutionarily conserved ER-associated degradation (ERAD) pathway. During ERAD, maturation-defective and surplus polypeptides are evicted from the ER lumen and/or lipid bilayer through the process of retrotranslocation and ultimately degraded by the proteasome. An integral facet of the ERAD mechanism is the ubiquitin system, composed of the ubiquitin modifier and the factors for assembling, processing and binding ubiquitin chains on conjugated substrates. Beyond simply marking polypeptides for degradation, the ubiquitin system is functionally intertwined with retrotranslocation machinery to transport polypeptides across the ER membrane.
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Affiliation(s)
- John C Christianson
- 1] Ludwig Institute for Cancer Research, University of Oxford, Oxford, UK. [2]
| | - Yihong Ye
- 1] Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA. [2]
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Xu L, Wang ZH, Xu D, Lin G, Li DR, Wan T, Guo SL. Expression of Derlin-1 and its effect on expression of autophagy marker genes under endoplasmic reticulum stress in lung cancer cells. Cancer Cell Int 2014; 14:50. [PMID: 24944523 PMCID: PMC4061450 DOI: 10.1186/1475-2867-14-50] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 06/05/2014] [Indexed: 12/05/2022] Open
Abstract
Background Recent findings indicated that Derlin-1 has an important function in tumour progression. In this study, we aimed to determine whether Derlin-1 has an oncogene function as a cross-talk molecule with autophagy. Methods Cancer cells were treated with tunicamycin (TM) for 8 and 24 h. The expression of Derlin-1 and autophagy-related genes was determined by western blot. Autophagy was analysed by fluorescence microscopy after staining the cancer cells with monodansylcadaverine. The interaction between Derlin-1 and other proteins was identified using co-immunoprecipitation assay. Results Our study demonstrated high Derlin-1 expression levels in most non-small lung cancer cell lines. Derlin-1 expression was enhanced under endoplasmic reticulum (ER) stress. Previous studies revealed that TM triggers the initiation of autophagy by activating Beclin 1, converting LC3I to LC3II and degrading p62. Knockdown of Derlin-1 did not affect Beclin 1 and LC3II expression but disrupted the degradation of p62 under ER stress, which resulted in the blockage of autophagy flux. Furthermore, Derlin-1 and p62 were observed to interact under ER stress. Conclusion This study is the first report about the interaction between Derlin-1 and p62. Derlin-1 may function in tumour progression partially by interacting with p62.
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Affiliation(s)
- Li Xu
- Department of Respiratory Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China
| | - Zan-Hong Wang
- Department of Obstetrics and Gynecology, The Shanxi Da Yi Hospital, Taiyuan 030001, P.R. China
| | - Dong Xu
- Center for Disease Control and Prevention, Gaoxin/Xinshi, District of Urumqi, Xinjiang Province, P.R. China
| | - Gang Lin
- Center for Disease Control and Prevention, Gaoxin/Xinshi, District of Urumqi, Xinjiang Province, P.R. China
| | - Dai-Rong Li
- Department of Respiratory Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China
| | - Tao Wan
- Department of Respiratory Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China
| | - Shu-Liang Guo
- Department of Respiratory Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China
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20
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Zhang T, Ye Y. The final moments of misfolded proteins en route to the proteasome. DNA Cell Biol 2014; 33:477-83. [PMID: 24833120 DOI: 10.1089/dna.2014.2452] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Protein homeostasis in the endoplasmic reticulum (ER) in eukaryotic cells is maintained by a conserved quality control system named ER-associated degradation (ERAD). The ERAD system retains misfolded or unassembled polypeptides in the ER, retrotranslocates them into the cytosol for degradation by the ubiquitin proteasome system. Central to the ERAD process is the AAA+ (ATPase associated with various cellular activities), ATPase p97/VCP (also known as Cdc48p in yeast), and the proteasome. p97/VCP couples ATP hydrolysis to the extraction of misfolded proteins from retrotranslocation sites and subsequently targets them for degradation, but how p97/VCP hands substrate off to the proteasome is unclear. Recent studies suggest that p97/VCP may either directly translocate polypeptides into the proteolytic compartment of the 20S subcomplex, or use a set of shuttling factors to deliver retrotranslocated polypeptides to the proteasome.
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Affiliation(s)
- Ting Zhang
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland
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21
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Abstract
Protein homoeostasis is a fundamental requirement for all living cells in order to survive in a dynamic surrounding. Proper levels of AIRAPL (arsenite-inducible RNA-associated protein-like protein) (ZFAND2B) are required in order to maintain cellular folding capacity in metazoans, and functional impairment of AIRAPL results in acceleration of aging and protein aggregation. However, the cellular roles of AIRAPL in this process are not known. In the present paper, we report that AIRAPL binds and forms a complex with p97 [VCP (valosin-containing protein)/Cdc48], Ubxd8 (ubiquitin regulatory X domain 8), Npl4-Ufd1, Derlin-1 and Bag6 on the ER (endoplasmic reticulum) membrane. In spite of the fact that AIRAPL complex partners are involved in the ERAD (ER-associated degradation) process, AIRAPL knockdown does not show any impairment in ERAD substrate degradation. However, translocation into the ER of a subset of ERAD- and non-ERAD-secreted proteins are regulated by AIRAPL. The ability to regulate translocation by the p97-AIRAPL complex is entirely dependent on the proteins' signal peptide. Our results demonstrate a p97 complex regulating translocation into the ER in a signal-peptide-dependent manner.
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22
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James LC. Intracellular antibody immunity and the cytosolic Fc receptor TRIM21. Curr Top Microbiol Immunol 2014; 382:51-66. [PMID: 25116095 DOI: 10.1007/978-3-319-07911-0_3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Until recently, it was thought that antibody effector mechanisms were mediated purely by Fc receptors expressed on professional cells, following capture of immune complexes in the extracellular space. Recently a new Fc receptor, TRIM21, was discovered that is expressed by cells of all histogenetic lineages and which mediates immune responses intracellularly. This new receptor possesses many unique structural and functional properties. TRIM21 binds both IgG and IgM, interacts primarily with the CH3 rather than CH2 domain and engages two heavy chains simultaneously. This latter property allows TRIM21 to bind antibodies with a higher affinity than any other Fc receptor. TRIM21 is cytosolic, has both effector and signalling functions and is exquisitely conserved in mammals. The discovery of this missing part of humoral immunity has important implications for where and how antibodies work.
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Affiliation(s)
- Leo C James
- MRC Laboratory of Molecular Biology, Cambridge, UK,
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23
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Sá-Moura B, Funakoshi M, Tomko RJ, Dohmen RJ, Wu Z, Peng J, Hochstrasser M. A conserved protein with AN1 zinc finger and ubiquitin-like domains modulates Cdc48 (p97) function in the ubiquitin-proteasome pathway. J Biol Chem 2013; 288:33682-33696. [PMID: 24121501 DOI: 10.1074/jbc.m113.521088] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Regulated protein degradation mediated by the ubiquitin-proteasome system (UPS) is critical to eukaryotic protein homeostasis. Often vital to degradation of protein substrates is their disassembly, unfolding, or extraction from membranes. These processes are catalyzed by the conserved AAA-ATPase Cdc48 (also known as p97). Here we characterize the Cuz1 protein (Cdc48-associated UBL/zinc finger protein-1), encoded by a previously uncharacterized arsenite-inducible gene in budding yeast. Cuz1, like its human ortholog ZFAND1, has both an AN1-type zinc finger (Zf_AN1) and a divergent ubiquitin-like domain (UBL). We show that Cuz1 modulates Cdc48 function in the UPS. The two proteins directly interact, and the Cuz1 UBL, but not Zf_AN1, is necessary for binding to the Cdc48 N-terminal domain. Cuz1 also associates, albeit more weakly, with the proteasome, and the UBL is dispensable for this interaction. Cuz1-proteasome interaction is strongly enhanced by exposure of cells to the environmental toxin arsenite, and in a proteasome mutant, loss of Cuz1 enhances arsenite sensitivity. Whereas loss of Cuz1 alone causes only minor UPS degradation defects, its combination with mutations in the Cdc48(Npl4-Ufd1) complex leads to much greater impairment. Cuz1 helps limit the accumulation of ubiquitin conjugates on both the proteasome and Cdc48, suggesting a possible role in the transfer of ubiquitylated substrates from Cdc48 to the proteasome or in their release from these complexes.
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Affiliation(s)
- Bebiana Sá-Moura
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520; Graduate Program in Areas of Basic and Applied Biology, Abel Salazar Biomedical Sciences Institute, University of Porto, Porto 4099-002, Portugal
| | - Minoru Funakoshi
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520
| | - Robert J Tomko
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520
| | - R Jürgen Dohmen
- Institute for Genetics, University of Cologne, Zülpicher Strasse 47, D-50674 Cologne, Germany
| | - Zhiping Wu
- Departments of Structural Biology and Developmental Neurobiology, St. Jude Proteomics Facility, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
| | - Junmin Peng
- Departments of Structural Biology and Developmental Neurobiology, St. Jude Proteomics Facility, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
| | - Mark Hochstrasser
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520.
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24
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Dec E, Rana P, Katheria V, Dec R, Khare M, Nalbandian A, Leu SY, Radom-Aizik S, Llewellyn K, BenMohamed L, Zaldivar F, Kimonis V. Cytokine profiling in patients with VCP-associated disease. Clin Transl Sci 2013; 7:29-32. [PMID: 24119107 DOI: 10.1111/cts.12117] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Valosin containing protein (VCP) disease (also known as Inclusion Body Myopathy, Paget Disease of Bone and Frontotemporal Dementia [IBMPFD] syndrome) is caused by mutations in the gene encoding VCP classically affecting the muscle, bone and brain. Although the genetic cause has been identified, details regarding the pathogenesis of IBMPFD have not been fully determined. Muscle wasting observed in VCP disease is suggestive of cytokine imbalance. We hypothesized that dysfunctional protein homeostasis caused by VCP mutations leads to cytokine imbalances thereby contributing to the muscle wasting phenotype. Circulating levels of interleukin-4 (IL-4), interleukin-6 (IL-6), tumor necrosis factor alpha (TNF a) and epidermal growth factor (EGF) were measured in plasma of patients with VCP disease or controls. TNF a and EGF were significantly altered in VCP disease as compared to control. TNF a was up-regulated, consistent with a cachexia phenotype and EGF levels were increased. No significant differences were observed in IL-4 and IL-6. Cytokine imbalances may be associated with VCP disease and may play a contributory role in VCP myopathy. Further understanding of how VCP dysfunction leads to aberrant protein homeostasis and subsequent cytokine imbalances may also aid in the understanding of other proteinopathies and in the development of novel treatments.
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Affiliation(s)
- Eric Dec
- Division of Genetics and Metabolism, Department of Pediatrics, University of California, Irvine, California, USA
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25
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Chen SF, Wu CH, Lee YM, Tam K, Tsai YC, Liou JY, Shyue SK. Caveolin-1 interacts with Derlin-1 and promotes ubiquitination and degradation of cyclooxygenase-2 via collaboration with p97 complex. J Biol Chem 2013; 288:33462-9. [PMID: 24089527 DOI: 10.1074/jbc.m113.521799] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Caveolin-1 (Cav-1) interacts with and mediates protein trafficking and various cellular functions. Derlin-1 is a candidate for the retrotranslocation channel of endoplasmic reticulum proteins. However, little is known about how Derlin-1 mediates glycosylated protein degradation. Here, we identified Cav-1 as a key player in Derlin-1- and p97-mediated cyclooxygenase 2 (COX-2) ubiquitination and degradation. Derlin-1 augmented the interaction of Cav-1 and COX-2 and mediated the degradation of COX-2 in a COX-2 C terminus-dependent manner. Suppression of Cav-1 decreased the ubiquitination of COX-2, and mutation of Asn-594 to Ala to disrupt N-glycosylation at the C terminus of COX-2 reduced the interaction of COX-2 with Cav-1 but not Derlin-1. Moreover, suppression of p97 increased the ubiquitination of COX-2 and up-regulated COX-2 but not COX-1. Cav-1 enhanced the interaction of p97 with Ufd1 and Derlin-1 and collaborated with p97 to interact with COX-2. Cav-1 may be a cofactor in the interaction of Derlin-1 and N-glycosylated COX-2 and may facilitate Derlin-1- and p97 complex-mediated COX-2 ubiquitination, retrotranslocation, and degradation.
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Affiliation(s)
- Shu-Fen Chen
- From the Cardiovascular Division, Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan
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26
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Palmer AL, Dolan BP. MHC class I antigen presentation of DRiP-derived peptides from a model antigen is not dependent on the AAA ATPase p97. PLoS One 2013; 8:e67796. [PMID: 23844095 PMCID: PMC3699533 DOI: 10.1371/journal.pone.0067796] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Accepted: 05/13/2013] [Indexed: 12/24/2022] Open
Abstract
CD8+ T cells are responsible for killing cells of the body that have become infected or oncogenically transformed. In order to do so, effector CD8+ T cells must recognize their cognate antigenic peptide bound to a MHC class I molecule that has been directly presented by the target cell. Due to the rapid nature of antigen presentation, it is believed that antigenic peptides are derived from a subset of newly synthesized proteins which are degraded almost immediately following synthesis and termed Defective Ribosomal Products or DRiPs. We have recently reported on a bioassay which can distinguish antigen presentation of DRiP substrates from other forms of rapidly degraded proteins and found that poly-ubiquitin chain disassembly may be necessary for efficient DRiP presentation. The AAA ATPase p97 protein is necessary for efficient cross-presentation of antigens on MHC class I molecules and plays an important role in extracting mis-folded proteins from the endoplasmic reticulum. Here, we find that genetic ablation or chemical inhibition of p97 does not diminish DRiP antigen presentation to any great extent nor does it alter the levels of MHC class I molecules on the cell surface, despite our observations that p97 inhibition increased the levels of poly-ubiquitinated proteins in the cell. These data demonstrate that inhibiting poly-ubiquitin chain disassembly alone is insufficient to abolish DRiP presentation.
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Affiliation(s)
- Amy L. Palmer
- Department of Biomedical Sciences, Oregon State University, Corvallis, Oregon, United States of America
| | - Brian P. Dolan
- Department of Biomedical Sciences, Oregon State University, Corvallis, Oregon, United States of America
- * E-mail:
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27
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Bipartite determinants mediate an evolutionarily conserved interaction between Cdc48 and the 20S peptidase. Proc Natl Acad Sci U S A 2013; 110:3327-32. [PMID: 23401548 DOI: 10.1073/pnas.1300408110] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Proteasomes are essential and ubiquitous ATP-dependent proteases that function in eukarya, archaea, and some bacteria. These destructive but critically important proteolytic machines use a 20S core peptidase and a hexameric ATPase associated with a variety of cellular activities (AAA+) unfolding ring that unfolds and spools substrates into the peptidase chamber. In archaea, 20S can function with the AAA+ Cdc48 or proteasome-activating nucleotidase (PAN) unfoldases. Both interactions are stabilized by C-terminal tripeptides in AAA+ subunits that dock into pockets on the 20S periphery. Here, we provide evidence that archaeal Cdc48 also uses a distinct set of near-axial interactions to bind 20S and propose that similar dual determinants mediate PAN-20S interactions and Rpt(1-6)-20S interactions in the 26S proteasome. Current dogma holds that the Rpt(1-6) unfolding ring of the 19S regulatory particle is the only AAA+ partner of eukaryotic 20S. By contrast, we show that mammalian Cdc48, a key player in cell-cycle regulation, membrane fusion, and endoplasmic-reticulum-associated degradation, activates mammalian 20S and find that a mouse Cdc48 variant supports protein degradation in combination with 20S. Our results suggest that eukaryotic Cdc48 orthologs function directly with 20S to maintain intracellular protein quality control.
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28
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Pick E, Berman TS. Formation of alternative proteasomes: same lady, different cap? FEBS Lett 2013; 587:389-93. [PMID: 23333296 DOI: 10.1016/j.febslet.2013.01.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Revised: 12/23/2012] [Accepted: 01/07/2013] [Indexed: 11/29/2022]
Abstract
The 26S proteasome is thought to be a homogenous complex, consisting of a 20S proteolytic core and a 19S regulatory particle that is required for its activation. Two groups have recently reported the activation of archeal 20S by a p97-related double-ring AAA+ ATPase complex, in a similar fashion to that reported for 19S. Since p97 is found in eukaryotes, the existence of a parallel setting in higher organisms is intriguing. Herein, we present supporting data and hypothesize that in eukaryotes, p97 and CSN form a promiscuous, hence hard-to-detect, "alternative cap", enabling the prompt and precise elimination of particular substrates.
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Affiliation(s)
- Elah Pick
- Department of Biology and Environment, Faculty of Natural Sciences, University of Haifa at Oranim, Tivon 36006, Israel.
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29
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Abstract
The chaperone-related, ubiquitin-selective AAA (ATPase associated with a variety of cellular activities) protein Cdc48 (also known as TER94, p97 and VCP) is a key regulator of intracellular proteolysis in eukaryotes. It uses the energy derived from ATP hydrolysis to segregate ubiquitylated proteins from stable assemblies with proteins, membranes and chromatin. Originally characterized as essential factor in proteasomal degradation pathways, Cdc48 was recently found to control lysosomal protein degradation as well. Moreover, impaired lysosomal proteolysis due to mutational inactivation of Cdc48 causes protein aggregation diseases in humans. This review introduces the major systems of intracellular proteolysis in eukaryotes and the role of protein ubiquitylation. It then discusses in detail structure, mechanism and cellular functions of Cdc48 with an emphasis on protein degradation pathways in yeast.
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Affiliation(s)
- Alexander Buchberger
- Department of Biochemistry, Biocenter, University of Würzburg, Am Hubland, 97074, Würzburg, Germany,
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30
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AAA ATPase p97/VCP is essential for TRIM21-mediated virus neutralization. Proc Natl Acad Sci U S A 2012; 109:19733-8. [PMID: 23091005 DOI: 10.1073/pnas.1210659109] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Tripartite motif-containing 21 (TRIM21) is a cytosolic IgG receptor that mediates intracellular virus neutralization by antibody. TRIM21 targets virions for destruction in the proteasome, but it is unclear how a substrate as large as a viral capsid is degraded. Here, we identify the ATPase p97/valosin-containing protein (VCP), an enzyme with segregase and unfoldase activity, as a key player in this process. Depletion or catalytic inhibition of VCP prevents capsid degradation and reduces neutralization. VCP is required concurrently with the proteasome, as addition of inhibitor after proteasomal degradation has no effect. Moreover, our results suggest that it is the challenging nature of virus as a substrate that necessitates involvement of VCP, since intracellularly expressed IgG Fc is degraded in a VCP-independent manner. These results implicate VCP as an important host factor in antiviral immunity.
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31
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Forouzan D, Ammelburg M, Hobel CF, Ströh LJ, Sessler N, Martin J, Lupas AN. The archaeal proteasome is regulated by a network of AAA ATPases. J Biol Chem 2012; 287:39254-62. [PMID: 22992741 PMCID: PMC3493965 DOI: 10.1074/jbc.m112.386458] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The proteasome is the central machinery for targeted protein degradation in archaea, Actinobacteria, and eukaryotes. In its basic form, it consists of a regulatory ATPase complex and a proteolytic core particle. The interaction between the two is governed by an HbYX motif (where Hb is a hydrophobic residue, Y is tyrosine, and X is any amino acid) at the C terminus of the ATPase subunits, which stimulates gate opening of the proteasomal α-subunits. In archaea, the proteasome-interacting motif is not only found in canonical proteasome-activating nucleotidases of the PAN/ARC/Rpt group, which are absent in major archaeal lineages, but also in proteins of the CDC48/p97/VAT and AMA groups, suggesting a regulatory network of proteasomal ATPases. Indeed, Thermoplasma acidophilum, which lacks PAN, encodes one CDC48 protein that interacts with the 20S proteasome and activates the degradation of model substrates. In contrast, Methanosarcina mazei contains seven AAA proteins, five of which, both PAN proteins, two out of three CDC48 proteins, and the AMA protein, function as proteasomal gatekeepers. The prevalent presence of multiple, distinct proteasomal ATPases in archaea thus results in a network of regulatory ATPases that may widen the substrate spectrum of proteasomal protein degradation.
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Affiliation(s)
- Dara Forouzan
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany
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