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Arkinson C, Dong KC, Gee CL, Martin A. Mechanisms and regulation of substrate degradation by the 26S proteasome. Nat Rev Mol Cell Biol 2024:10.1038/s41580-024-00778-0. [PMID: 39362999 DOI: 10.1038/s41580-024-00778-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/23/2024] [Indexed: 10/05/2024]
Abstract
The 26S proteasome is involved in degrading and regulating the majority of proteins in eukaryotic cells, which requires a sophisticated balance of specificity and promiscuity. In this Review, we discuss the principles that underly substrate recognition and ATP-dependent degradation by the proteasome. We focus on recent insights into the mechanisms of conventional ubiquitin-dependent and ubiquitin-independent protein turnover, and discuss the plethora of modulators for proteasome function, including substrate-delivering cofactors, ubiquitin ligases and deubiquitinases that enable the targeting of a highly diverse substrate pool. Furthermore, we summarize recent progress in our understanding of substrate processing upstream of the 26S proteasome by the p97 protein unfoldase. The advances in our knowledge of proteasome structure, function and regulation also inform new strategies for specific inhibition or harnessing the degradation capabilities of the proteasome for the treatment of human diseases, for instance, by using proteolysis targeting chimera molecules or molecular glues.
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Affiliation(s)
- Connor Arkinson
- California Institute for Quantitative Biosciences, University of California at Berkeley, Berkeley, CA, USA
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA, USA
- Howard Hughes Medical Institute, University of California at Berkeley, Berkeley, CA, USA
| | - Ken C Dong
- Howard Hughes Medical Institute, University of California at Berkeley, Berkeley, CA, USA
| | - Christine L Gee
- California Institute for Quantitative Biosciences, University of California at Berkeley, Berkeley, CA, USA
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA, USA
- Howard Hughes Medical Institute, University of California at Berkeley, Berkeley, CA, USA
| | - Andreas Martin
- California Institute for Quantitative Biosciences, University of California at Berkeley, Berkeley, CA, USA.
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA, USA.
- Howard Hughes Medical Institute, University of California at Berkeley, Berkeley, CA, USA.
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2
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Gao R, Wu Y, Wang Y, Yang Z, Mao Y, Yang Y, Yang C, Chen Z. Ubiquitination and De-Ubiquitination in the Synthesis of Cow Milk Fat: Reality and Prospects. Molecules 2024; 29:4093. [PMID: 39274941 PMCID: PMC11397273 DOI: 10.3390/molecules29174093] [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: 07/19/2024] [Revised: 08/26/2024] [Accepted: 08/27/2024] [Indexed: 09/16/2024] Open
Abstract
Ubiquitination modifications permit the degradation of labelled target proteins with the assistance of proteasomes and lysosomes, which is the main protein degradation pathway in eukaryotic cells. Polyubiquitination modifications of proteins can also affect their functions. De-ubiquitinating enzymes reverse the process of ubiquitination via cleavage of the ubiquitin molecule, which is known as a de-ubiquitination. It was demonstrated that ubiquitination and de-ubiquitination play key regulatory roles in fatty acid transport, de novo synthesis, and desaturation in dairy mammary epithelial cells. In addition, natural plant extracts, such as stigmasterol, promote milk fat synthesis in epithelial cells via the ubiquitination pathway. This paper reviews the current research on ubiquitination and de-ubiquitination in dairy milk fat production, with a view to providing a reference for subsequent research on milk fat and exploring new directions for the improvement of milk quality.
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Affiliation(s)
- Rui Gao
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China
| | - Yanni Wu
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China
| | - Yuhao Wang
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China
| | - Zhangping Yang
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China
| | - Yongjiang Mao
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China
| | - Yi Yang
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China
| | - Chunhua Yang
- Institute of Biological Resources, Jiangxi Academy of Sciences, Nanchang 330029, China
| | - Zhi Chen
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China
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3
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Negi H, Ravichandran A, Dasgupta P, Reddy S, Das R. Plasticity of the proteasome-targeting signal Fat10 enhances substrate degradation. eLife 2024; 13:e91122. [PMID: 38984715 PMCID: PMC11299979 DOI: 10.7554/elife.91122] [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: 07/20/2023] [Accepted: 07/09/2024] [Indexed: 07/11/2024] Open
Abstract
The proteasome controls levels of most cellular proteins, and its activity is regulated under stress, quiescence, and inflammation. However, factors determining the proteasomal degradation rate remain poorly understood. Proteasome substrates are conjugated with small proteins (tags) like ubiquitin and Fat10 to target them to the proteasome. It is unclear if the structural plasticity of proteasome-targeting tags can influence substrate degradation. Fat10 is upregulated during inflammation, and its substrates undergo rapid proteasomal degradation. We report that the degradation rate of Fat10 substrates critically depends on the structural plasticity of Fat10. While the ubiquitin tag is recycled at the proteasome, Fat10 is degraded with the substrate. Our results suggest significantly lower thermodynamic stability and faster mechanical unfolding in Fat10 compared to ubiquitin. Long-range salt bridges are absent in the Fat10 structure, creating a plastic protein with partially unstructured regions suitable for proteasome engagement. Fat10 plasticity destabilizes substrates significantly and creates partially unstructured regions in the substrate to enhance degradation. NMR-relaxation-derived order parameters and temperature dependence of chemical shifts identify the Fat10-induced partially unstructured regions in the substrate, which correlated excellently to Fat10-substrate contacts, suggesting that the tag-substrate collision destabilizes the substrate. These results highlight a strong dependence of proteasomal degradation on the structural plasticity and thermodynamic properties of the proteasome-targeting tags.
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Affiliation(s)
- Hitendra Negi
- National Center for Biological Sciences, Tata Institute of Fundamental ResearchBangaloreIndia
- SASTRA University, ThirumalaisamudramThanjavurIndia
| | - Aravind Ravichandran
- National Center for Biological Sciences, Tata Institute of Fundamental ResearchBangaloreIndia
- SASTRA University, ThirumalaisamudramThanjavurIndia
| | - Pritha Dasgupta
- National Center for Biological Sciences, Tata Institute of Fundamental ResearchBangaloreIndia
| | - Shridivya Reddy
- National Center for Biological Sciences, Tata Institute of Fundamental ResearchBangaloreIndia
| | - Ranabir Das
- National Center for Biological Sciences, Tata Institute of Fundamental ResearchBangaloreIndia
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4
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Arkinson C, Dong KC, Gee CL, Costello SM, Marqusee S, Martin A. Nub1 traps unfolded FAT10 for ubiquitin-independent degradation by the 26S proteasome. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.12.598715. [PMID: 38915702 PMCID: PMC11195292 DOI: 10.1101/2024.06.12.598715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
The ubiquitin-like modifier FAT10 targets hundreds of proteins in the mammalian immune system to the 26S proteasome for degradation. This degradation pathway requires the cofactor Nub1, yet the underlying mechanisms remain unknown. Here, we reconstituted a minimal in vitro system and revealed that Nub1 utilizes FAT10's intrinsic instability to trap its N-terminal ubiquitin-like domain in an unfolded state and deliver it to the 26S proteasome for engagement, allowing the degradation of FAT10-ylated substrates in a ubiquitin- and p97-independent manner. Through hydrogen-deuterium exchange, structural modeling, and site-directed mutagenesis, we identified the formation of a peculiar complex with FAT10 that activates Nub1 for docking to the 26S proteasome, and our cryo-EM studies visualized the highly dynamic Nub1 complex bound to the proteasomal Rpn1 subunit during FAT10 delivery and the early stages of ATP-dependent degradation. These studies thus identified a novel mode of cofactor-mediated, ubiquitin-independent substrate delivery to the 26S proteasome that relies on trapping partially unfolded states for engagement by the proteasomal ATPase motor.
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Affiliation(s)
- Connor Arkinson
- California Institute for Quantitative Biosciences, University of California at Berkeley, Berkeley, CA94720, USA
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA94720, USA
- Howard Hughes Medical Institute, University of California at Berkeley, Berkeley, CA94720, USA
| | - Ken C. Dong
- Howard Hughes Medical Institute, University of California at Berkeley, Berkeley, CA94720, USA
| | - Christine L. Gee
- California Institute for Quantitative Biosciences, University of California at Berkeley, Berkeley, CA94720, USA
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA94720, USA
- Howard Hughes Medical Institute, University of California at Berkeley, Berkeley, CA94720, USA
| | - Shawn M. Costello
- Biophysics Graduate Program, University of California, Berkeley, CA, USA
| | - Susan Marqusee
- California Institute for Quantitative Biosciences, University of California at Berkeley, Berkeley, CA94720, USA
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA94720, USA
- Department of Chemistry, University of California, Berkeley, CA, USA
- Chan Zuckerberg Biohub, San Francisco, CA, USA
| | - Andreas Martin
- California Institute for Quantitative Biosciences, University of California at Berkeley, Berkeley, CA94720, USA
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA94720, USA
- Howard Hughes Medical Institute, University of California at Berkeley, Berkeley, CA94720, USA
- Lead contact
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5
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Gubat J, Sjöstrand L, Selvaraju K, Telli K, D'Arcy P. Loss of the proteasomal deubiquitinase USP14 induces growth defects and a senescence phenotype in colorectal cancer cells. Sci Rep 2024; 14:13037. [PMID: 38844605 PMCID: PMC11156967 DOI: 10.1038/s41598-024-63791-5] [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: 01/11/2024] [Accepted: 06/03/2024] [Indexed: 06/09/2024] Open
Abstract
The proteasome-associated deubiquitinase USP14 is a potential drug target. Using an inducible USP14 knockout system in colon cancer cells, we found that USP14 depletion impedes cellular proliferation, induces cell cycle arrest, and leads to a senescence-like phenotype. Transcriptomic analysis revealed altered gene expression related to cell division and cellular differentiation. USP14 knockout cells also exhibited changes in morphology, actin distribution, and expression of actin cytoskeletal components. Increased ubiquitin turnover was observed, offset by upregulation of polyubiquitin genes UBB and UBC. Pharmacological inhibition of USP14 with IU1 increased ubiquitin turnover but did not affect cellular growth or morphology. BioGRID data identified USP14 interactors linked to actin cytoskeleton remodeling, DNA damage repair, mRNA splicing, and translation. In conclusion, USP14 loss in colon cancer cells induces a transient quiescent cancer phenotype not replicated by pharmacologic inhibition of its deubiquitinating activity.
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Affiliation(s)
- Johannes Gubat
- Department of Biomedical and Clinical Sciences, Linköping University, 581 83, Linköping, Sweden
| | - Linda Sjöstrand
- Department of Biomedical and Clinical Sciences, Linköping University, 581 83, Linköping, Sweden
| | - Karthik Selvaraju
- Department of Biomedical and Clinical Sciences, Linköping University, 581 83, Linköping, Sweden
| | - Kübra Telli
- Department of Biomedical and Clinical Sciences, Linköping University, 581 83, Linköping, Sweden
| | - Pádraig D'Arcy
- Department of Biomedical and Clinical Sciences, Linköping University, 581 83, Linköping, Sweden.
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Xiong J, Pang X, Song X, Yang L, Pang C. The coherence between PSMC6 and α-ring in the 26S proteasome is associated with Alzheimer's disease. Front Mol Neurosci 2024; 16:1330853. [PMID: 38357597 PMCID: PMC10864545 DOI: 10.3389/fnmol.2023.1330853] [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: 10/31/2023] [Accepted: 12/22/2023] [Indexed: 02/16/2024] Open
Abstract
Alzheimer's disease (AD) is a heterogeneous age-dependent neurodegenerative disorder. Its hallmarks involve abnormal proteostasis, which triggers proteotoxicity and induces neuronal dysfunction. The 26S proteasome is an ATP-dependent proteolytic nanomachine of the ubiquitin-proteasome system (UPS) and contributes to eliminating these abnormal proteins. This study focused on the relationship between proteasome and AD, the hub genes of proteasome, PSMC6, and 7 genes of α-ring, are selected as targets to study. The following three characteristics were observed: 1. The total number of proteasomes decreased with AD progression because the proteotoxicity damaged the expression of proteasome proteins, as evidenced by the downregulation of hub genes. 2. The existing proteasomes exhibit increased activity and efficiency to counterbalance the decline in total proteasome numbers, as evidenced by enhanced global coordination and reduced systemic disorder of proteasomal subunits as AD advances. 3. The synergy of PSMC6 and α-ring subunits is associated with AD. Synergistic downregulation of PSMC6 and α-ring subunits reflects a high probability of AD risk. Regarding the above discovery, the following hypothesis is proposed: The aggregation of pathogenic proteins intensifies with AD progression, then proteasome becomes more active and facilitates the UPS selectively targets the degradation of abnormal proteins to maintain CNS proteostasis. In this paper, bioinformatics and support vector machine learning methods are applied and combined with multivariate statistical analysis of microarray data. Additionally, the concept of entropy was used to detect the disorder of proteasome system, it was discovered that entropy is down-regulated continually with AD progression against system chaos caused by AD. Another conception of the matrix determinant was used to detect the global coordination of proteasome, it was discovered that the coordination is enhanced to maintain the efficiency of degradation. The features of entropy and determinant suggest that active proteasomes resist the attack caused by AD like defenders, on the one hand, to protect themselves (entropy reduces), and on the other hand, to fight the enemy (determinant reduces). It is noted that these are results from biocomputing and need to be supported by further biological experiments.
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Affiliation(s)
- Jing Xiong
- College of Computer Science, Sichuan Normal University, Chengdu, China
| | - Xinping Pang
- West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, China
| | - Xianghu Song
- College of Computer Science, Sichuan Normal University, Chengdu, China
| | - Lin Yang
- College of Computer Science, Sichuan Normal University, Chengdu, China
| | - Chaoyang Pang
- College of Computer Science, Sichuan Normal University, Chengdu, China
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7
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Liu Q, Maqbool A, Mirkin FG, Singh Y, Stevenson CEM, Lawson DM, Kamoun S, Huang W, Hogenhout SA. Bimodular architecture of bacterial effector SAP05 that drives ubiquitin-independent targeted protein degradation. Proc Natl Acad Sci U S A 2023; 120:e2310664120. [PMID: 38039272 DOI: 10.1073/pnas.2310664120] [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: 06/26/2023] [Accepted: 10/19/2023] [Indexed: 12/03/2023] Open
Abstract
In eukaryotes, targeted protein degradation (TPD) typically depends on a series of interactions among ubiquitin ligases that transfer ubiquitin molecules to substrates leading to degradation by the 26S proteasome. We previously identified that the bacterial effector protein SAP05 mediates ubiquitin-independent TPD. SAP05 forms a ternary complex via interactions with the von Willebrand Factor Type A (vWA) domain of the proteasomal ubiquitin receptor Rpn10 and the zinc-finger (ZnF) domains of the SQUAMOSA-PROMOTER BINDING PROTEIN-LIKE (SPL) and GATA BINDING FACTOR (GATA) transcription factors (TFs). This leads to direct TPD of the TFs by the 26S proteasome. Here, we report the crystal structures of the SAP05-Rpn10vWA complex at 2.17 Å resolution and of the SAP05-SPL5ZnF complex at 2.20 Å resolution. Structural analyses revealed that SAP05 displays a remarkable bimodular architecture with two distinct nonoverlapping surfaces, a "loop surface" with three protruding loops that form electrostatic interactions with ZnF, and a "sheet surface" featuring two β-sheets, loops, and α-helices that establish polar interactions with vWA. SAP05 binding to ZnF TFs involves single amino acids responsible for multiple contacts, while SAP05 binding to vWA is more stable due to the necessity of multiple mutations to break the interaction. In addition, positioning of the SAP05 complex on the 26S proteasome points to a mechanism of protein degradation. Collectively, our findings demonstrate how a small bacterial bimodular protein can bypass the canonical ubiquitin-proteasome proteolysis pathway, enabling ubiquitin-independent TPD in eukaryotic cells. This knowledge holds significant potential for the creation of TPD technologies.
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Affiliation(s)
- Qun Liu
- Department of Crop Genetics, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom
| | - Abbas Maqbool
- Department of Biochemistry and Metabolism, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom
- The Sainsbury Laboratory, University of East Anglia, Norwich NR4 7UH, United Kingdom
| | - Federico G Mirkin
- Department of Crop Genetics, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom
| | - Yeshveer Singh
- Department of Crop Genetics, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom
| | - Clare E M Stevenson
- Department of Biochemistry and Metabolism, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom
| | - David M Lawson
- Department of Biochemistry and Metabolism, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom
| | - Sophien Kamoun
- The Sainsbury Laboratory, University of East Anglia, Norwich NR4 7UH, United Kingdom
| | - Weijie Huang
- National Key Laboratory of Plant Molecular Genetics, Shanghai Centre for Plant Stress Biology, Centre for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 20032, China
| | - Saskia A Hogenhout
- Department of Crop Genetics, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom
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8
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Lee D, Zhu Y, Colson L, Wang X, Chen S, Tkacik E, Huang L, Ouyang Q, Goldberg AL, Lu Y. Molecular mechanism for activation of the 26S proteasome by ZFAND5. Mol Cell 2023; 83:2959-2975.e7. [PMID: 37595557 PMCID: PMC10523585 DOI: 10.1016/j.molcel.2023.07.023] [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: 11/07/2022] [Revised: 05/07/2023] [Accepted: 07/24/2023] [Indexed: 08/20/2023]
Abstract
Various hormones, kinases, and stressors (fasting, heat shock) stimulate 26S proteasome activity. To understand how its capacity to degrade ubiquitylated proteins can increase, we studied mouse ZFAND5, which promotes protein degradation during muscle atrophy. Cryo-electron microscopy showed that ZFAND5 induces large conformational changes in the 19S regulatory particle. ZFAND5's AN1 Zn-finger domain interacts with the Rpt5 ATPase and its C terminus with Rpt1 ATPase and Rpn1, a ubiquitin-binding subunit. Upon proteasome binding, ZFAND5 widens the entrance of the substrate translocation channel, yet it associates only transiently with the proteasome. Dissociation of ZFAND5 then stimulates opening of the 20S proteasome gate. Using single-molecule microscopy, we showed that ZFAND5 binds ubiquitylated substrates, prolongs their association with proteasomes, and increases the likelihood that bound substrates undergo degradation, even though ZFAND5 dissociates before substrate deubiquitylation. These changes in proteasome conformation and reaction cycle can explain the accelerated degradation and suggest how other proteasome activators may stimulate proteolysis.
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Affiliation(s)
- Donghoon Lee
- Department of Cell Biology, Harvard Medical School, Boston, MA USA
| | - Yanan Zhu
- Department of Systems Biology, Harvard Medical School, Boston, MA USA; Center for Quantitative Biology, Peking University, Beijing, China; State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, School of Physics, Peking University, Beijing, China
| | - Louis Colson
- Department of Systems Biology, Harvard Medical School, Boston, MA USA
| | - Xiaorong Wang
- School of Medicine, University of California Irvine, Irvine, Irvine, CA USA
| | - Siyi Chen
- Department of Systems Biology, Harvard Medical School, Boston, MA USA
| | - Emre Tkacik
- Department of Systems Biology, Harvard Medical School, Boston, MA USA
| | - Lan Huang
- School of Medicine, University of California Irvine, Irvine, Irvine, CA USA
| | - Qi Ouyang
- Center for Quantitative Biology, Peking University, Beijing, China; State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, School of Physics, Peking University, Beijing, China; Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | | | - Ying Lu
- Department of Systems Biology, Harvard Medical School, Boston, MA USA.
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Betancourt D, Lawal T, Tomko RJ. Wiggle and Shake: Managing and Exploiting Conformational Dynamics during Proteasome Biogenesis. Biomolecules 2023; 13:1223. [PMID: 37627288 PMCID: PMC10452565 DOI: 10.3390/biom13081223] [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: 07/04/2023] [Revised: 08/01/2023] [Accepted: 08/03/2023] [Indexed: 08/27/2023] Open
Abstract
The 26S proteasome is the largest and most complicated protease known, and changes to proteasome assembly or function contribute to numerous human diseases. Assembly of the 26S proteasome from its ~66 individual polypeptide subunits is a highly orchestrated process requiring the concerted actions of both intrinsic elements of proteasome subunits, as well as assistance by extrinsic, dedicated proteasome assembly chaperones. With the advent of near-atomic resolution cryo-electron microscopy, it has become evident that the proteasome is a highly dynamic machine, undergoing numerous conformational changes in response to ligand binding and during the proteolytic cycle. In contrast, an appreciation of the role of conformational dynamics during the biogenesis of the proteasome has only recently begun to emerge. Herein, we review our current knowledge of proteasome assembly, with a particular focus on how conformational dynamics guide particular proteasome biogenesis events. Furthermore, we highlight key emerging questions in this rapidly expanding area.
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Affiliation(s)
| | | | - Robert J. Tomko
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, FL 32306, USA; (D.B.); (T.L.)
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Brockmann F, Catone N, Wünsch C, Offensperger F, Scheffner M, Schmidtke G, Aichem A. FAT10 and NUB1L cooperate to activate the 26S proteasome. Life Sci Alliance 2023; 6:e202201463. [PMID: 37188463 PMCID: PMC10185811 DOI: 10.26508/lsa.202201463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 05/02/2023] [Accepted: 05/03/2023] [Indexed: 05/17/2023] Open
Abstract
The interaction of the 19S regulatory particle of the 26S proteasome with ubiquitylated proteins leads to gate opening of the 20S core particle and increases its proteolytic activity by binding of the ubiquitin chain to the inhibitory deubiquitylation enzyme USP14 on the 19S regulatory subunit RPN1. Covalent modification of proteins with the cytokine inducible ubiquitin-like modifier FAT10 is an alternative signal for proteasomal degradation. Here, we report that FAT10 and its interaction partner NUB1L facilitate the gate opening of the 20S proteasome in an ubiquitin- and USP14-independent manner. We also show that FAT10 is capable to activate all peptidolytic activities of the 26S proteasome, however only together with NUB1L, by binding to the UBA domains of NUB1L and thereby interfering with NUB1L dimerization. The binding of FAT10 to NUB1L leads to an increased affinity of NUB1L for the subunit RPN1. In conclusion, the herein described cooperation of FAT10 and NUB1L is a substrate-induced mechanism to activate the 26S proteasome.
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Affiliation(s)
- Florian Brockmann
- Division of Immunology, Department of Biology, University of Konstanz, Konstanz, Germany
| | - Nicola Catone
- Biotechnology Institute Thurgauhttps://ror.org/0546hnb39 at the University of Konstanz, Kreuzlingen, Switzerland
| | - Christine Wünsch
- Division of Immunology, Department of Biology, University of Konstanz, Konstanz, Germany
| | - Fabian Offensperger
- Division of Biochemistry, Department of Biology, University of Konstanz, Konstanz, Germany
| | - Martin Scheffner
- Division of Biochemistry, Department of Biology, University of Konstanz, Konstanz, Germany
| | - Gunter Schmidtke
- Division of Immunology, Department of Biology, University of Konstanz, Konstanz, Germany
| | - Annette Aichem
- Division of Immunology, Department of Biology, University of Konstanz, Konstanz, Germany
- Biotechnology Institute Thurgauhttps://ror.org/0546hnb39 at the University of Konstanz, Kreuzlingen, Switzerland
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11
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Zhang H, Ji S, Zhang K, Chen Y, Ming J, Kong F, Wang L, Wang S, Zou Z, Xiong Z, Xu K, Lin Z, Huang B, Liu L, Fan Q, Jin S, Deng H, Xie W. Stable maternal proteins underlie distinct transcriptome, translatome, and proteome reprogramming during mouse oocyte-to-embryo transition. Genome Biol 2023; 24:166. [PMID: 37443062 PMCID: PMC10347836 DOI: 10.1186/s13059-023-02997-8] [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: 09/14/2022] [Accepted: 06/27/2023] [Indexed: 07/15/2023] Open
Abstract
BACKGROUND The oocyte-to-embryo transition (OET) converts terminally differentiated gametes into a totipotent embryo and is critically controlled by maternal mRNAs and proteins, while the genome is silent until zygotic genome activation. How the transcriptome, translatome, and proteome are coordinated during this critical developmental window remains poorly understood. RESULTS Utilizing a highly sensitive and quantitative mass spectrometry approach, we obtain high-quality proteome data spanning seven mouse stages, from full-grown oocyte (FGO) to blastocyst, using 100 oocytes/embryos at each stage. Integrative analyses reveal distinct proteome reprogramming compared to that of the transcriptome or translatome. FGO to 8-cell proteomes are dominated by FGO-stockpiled proteins, while the transcriptome and translatome are more dynamic. FGO-originated proteins frequently persist to blastocyst while corresponding transcripts are already downregulated or decayed. Improved concordance between protein and translation or transcription is observed for genes starting translation upon meiotic resumption, as well as those transcribed and translated only in embryos. Concordance between protein and transcription/translation is also observed for proteins with short half-lives. We built a kinetic model that predicts protein dynamics by incorporating both initial protein abundance in FGOs and translation kinetics across developmental stages. CONCLUSIONS Through integrative analyses of datasets generated by ultrasensitive methods, our study reveals that the proteome shows distinct dynamics compared to the translatome and transcriptome during mouse OET. We propose that the remarkably stable oocyte-originated proteome may help save resources to accommodate the demanding needs of growing embryos. This study will advance our understanding of mammalian OET and the fundamental principles governing gene expression.
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Affiliation(s)
- Hongmei Zhang
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, New Cornerstone Science Laboratory, School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Shuyan Ji
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, New Cornerstone Science Laboratory, School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Ke Zhang
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, New Cornerstone Science Laboratory, School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Yuling Chen
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Jia Ming
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, New Cornerstone Science Laboratory, School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Feng Kong
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, New Cornerstone Science Laboratory, School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Lijuan Wang
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, New Cornerstone Science Laboratory, School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Shun Wang
- School of Mathematics and Statistics, Wuhan University, Wuhan, China
- Hubei Key Laboratory of Computational Science, Wuhan University, Wuhan, China
| | - Zhuoning Zou
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, New Cornerstone Science Laboratory, School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China
| | - Zhuqing Xiong
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, New Cornerstone Science Laboratory, School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Kai Xu
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, New Cornerstone Science Laboratory, School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Zili Lin
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, New Cornerstone Science Laboratory, School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Bo Huang
- Zhejiang Provincial Key Laboratory of Pancreatic Disease, School of Medicine, the First Affiliated Hospital, Zhejiang University, Hangzhou, 310002, China
| | - Ling Liu
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, New Cornerstone Science Laboratory, School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Qiang Fan
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, New Cornerstone Science Laboratory, School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Suoqin Jin
- School of Mathematics and Statistics, Wuhan University, Wuhan, China
| | - Haiteng Deng
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Wei Xie
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, New Cornerstone Science Laboratory, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
- Tsinghua-Peking Center for Life Sciences, Beijing, China.
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12
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Oliveri F, Keller SJ, Goebel H, Alvarez Salinas GO, Basler M. The ubiquitin-like modifier FAT10 is degraded by the 20S proteasome in vitro but not in cellulo. Life Sci Alliance 2023; 6:e202201760. [PMID: 37012049 PMCID: PMC10070814 DOI: 10.26508/lsa.202201760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 03/23/2023] [Accepted: 03/23/2023] [Indexed: 04/05/2023] Open
Abstract
Ubiquitin-independent protein degradation via the 20S proteasome without the 19S regulatory particle has gained increasing attention over the last years. The degradation of the ubiquitin-like modifier FAT10 by the 20S proteasome was investigated in this study. We found that FAT10 was rapidly degraded by purified 20S proteasomes in vitro, which was attributed to the weak folding of FAT10 and the N-terminally disordered tail. To confirm our results in cellulo, we established an inducible RNA interference system in which the AAA-ATPase Rpt2 of the 19S regulatory particle is knocked down to impair the function of the 26S proteasome. Using this system, degradation of FAT10 in cellulo was strongly dependent on functional 26S proteasome. Our data indicate that in vitro degradation studies with purified proteins do not necessarily reflect biological degradation mechanisms occurring in cells and, therefore, cautious data interpretation is required when 20S proteasome function is studied in vitro.
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Affiliation(s)
- Franziska Oliveri
- Division of Immunology, Department of Biology, University of Konstanz, Konstanz, Germany
| | | | - Heike Goebel
- Division of Immunology, Department of Biology, University of Konstanz, Konstanz, Germany
| | | | - Michael Basler
- Division of Immunology, Department of Biology, University of Konstanz, Konstanz, Germany;
- Biotechnology Institute Thurgau https://ror.org/0546hnb39 at the University of Konstanz, Kreuzlingen, Switzerland
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13
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Krüger G, Kirkpatrick J, Mahieu E, Franzetti B, Gabel F, Carlomagno T. An NMR Study of a 300-kDa AAA+ Unfoldase. J Mol Biol 2023; 435:167997. [PMID: 37330287 DOI: 10.1016/j.jmb.2023.167997] [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: 11/07/2022] [Revised: 01/20/2023] [Accepted: 01/30/2023] [Indexed: 06/19/2023]
Abstract
AAA+ ATPases are ubiquitous hexameric unfoldases acting in cellular protein quality control. In complex with proteases, they form protein degradation machinery (the proteasome) in both archaea and eukaryotes. Here, we use solution-state NMR spectroscopy to determine the symmetry properties of the archaeal PAN AAA+ unfoldase and gain insights into its functional mechanism. PAN consists of three folded domains: the coiled-coil (CC), OB and ATPase domains. We find that full-length PAN assembles into a hexamer with C2 symmetry, and that this symmetry extends over the CC, OB and ATPase domains. The NMR data, collected in the absence of substrate, are incompatible with the spiral staircase structure observed in electron-microscopy studies of archaeal PAN in the presence of substrate and in electron-microscopy studies of eukaryotic unfoldases both in the presence and in the absence of substrate. Based on the C2 symmetry revealed by NMR spectroscopy in solution, we propose that archaeal ATPases are flexible enzymes, which can adopt distinct conformations in different conditions. This study reaffirms the importance of studying dynamic systems in solution.
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Affiliation(s)
- Georg Krüger
- Centre of Biomolecular Drug Research and Institute of Organic Chemistry, Leibniz University Hannover, Schneiderberg 38, 30167 Hannover, Germany
| | - John Kirkpatrick
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Emilie Mahieu
- Univ. Grenoble Alpes, CEA, CNRS, IBS, 71 avenue des Martyrs, F-38000 Grenoble, France
| | - Bruno Franzetti
- Univ. Grenoble Alpes, CEA, CNRS, IBS, 71 avenue des Martyrs, F-38000 Grenoble, France
| | - Frank Gabel
- Univ. Grenoble Alpes, CEA, CNRS, IBS, 71 avenue des Martyrs, F-38000 Grenoble, France
| | - Teresa Carlomagno
- Centre of Biomolecular Drug Research and Institute of Organic Chemistry, Leibniz University Hannover, Schneiderberg 38, 30167 Hannover, Germany; School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK; Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
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14
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Lee D, Zhu Y, Colson L, Wang X, Chen S, Tkacik E, Huang L, Ouyang Q, Goldberg AL, Lu Y. Molecular mechanisms for activation of the 26S proteasome. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.09.540094. [PMID: 37214989 PMCID: PMC10197607 DOI: 10.1101/2023.05.09.540094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Various hormones, kinases, and stressors (fasting, heat shock) stimulate 26S proteasome activity. To understand how its capacity to degrade ubiquitylated protein can increase, we studied ZFAND5, which promotes protein degradation during muscle atrophy. Cryo-electron microscopy showed that ZFAND5 induces large conformational changes in the 19S regulatory particle. ZFAND5's AN1 Zn finger interacts with the Rpt5 ATPase and its C-terminus with Rpt1 ATPase and Rpn1, a ubiquitin-binding subunit. Surprisingly, these C-terminal interactions are sufficient to activate proteolysis. With ZFAND5 bound, entry into the proteasome's protein translocation channel is wider, and ZFAND5 dissociation causes opening of the 20S gate for substrate entry. Using single-molecular microscopy, we showed that ZFAND5 binds ubiquitylated substrates, prolongs their association with proteasomes, and increases the likelihood that bound substrates undergo degradation, even though ZFAND5 dissociates before substrate deubiquitylation. These changes in proteasome conformation and reaction cycle can explain the accelerated degradation and suggest how other proteasome activators may stimulate proteolysis.
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15
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Krüger G, Kirkpatrick J, Mahieu E, Franzetti B, Gabel F, Carlomagno T. A real-time analysis of GFP unfolding by the AAA+ unfoldase PAN. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2023; 350:107431. [PMID: 37058954 DOI: 10.1016/j.jmr.2023.107431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/27/2023] [Accepted: 03/30/2023] [Indexed: 05/10/2023]
Abstract
Protein quality control systems are essential to maintain a healthy proteome. They often consist of an unfoldase unit, typically an AAA+ ATPase, coupled with a protease unit. In all kingdoms of life, they function to eliminate misfolded proteins, and thus prevent that their aggregates do harm to the cell, and to rapidly regulate protein levels in the presence of environmental changes. Despite the huge progress made in the past two decades in understanding the mechanism of function of protein degradation systems, the fate of the substrate during the unfolding and proteolytic processes remains poorly understood. Here we exploit an NMR-based approach to monitor GFP processing by the archaeal PAN unfoldase and the PAN-20S degradation system in real time. We find that PAN-dependent unfolding of GFP does not involve the release of partially-folded GFP molecules resulting from futile unfolding attempts. In contrast, once stably engaged with PAN, GFP molecules are efficiently transferred to the proteolytic chamber of the 20S subunit, despite the only weak affinity of PAN for the 20S subunit in the absence of substrate. This is essential to guarantee that unfolded but not proteolyzed proteins are not released into solution, where they would form toxic aggregates. The results of our studies are in good agreement with previous results derived from real-time small-angle-neutron-scattering experiments and have the advantage of allowing the investigation of substrates and products at amino-acid resolution.
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Affiliation(s)
- Georg Krüger
- Institute of Organic Chemistry and Centre of Biomolecular Drug Design, Leibniz University Hannover, Schneiderberg 38, D-30167 Hannover, Germany
| | - John Kirkpatrick
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, B15 2TT Birmingham, United Kingdom
| | - Emilie Mahieu
- Univ. Grenoble Alpes, CEA, CNRS, IBS, 71 avenue des Martyrs, F-38000 Grenoble, France
| | - Bruno Franzetti
- Univ. Grenoble Alpes, CEA, CNRS, IBS, 71 avenue des Martyrs, F-38000 Grenoble, France
| | - Frank Gabel
- Univ. Grenoble Alpes, CEA, CNRS, IBS, 71 avenue des Martyrs, F-38000 Grenoble, France
| | - Teresa Carlomagno
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, B15 2TT Birmingham, United Kingdom.
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16
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Sekaran S, Park S. The penultimate step of proteasomal ATPase assembly is mediated by a switch dependent on the chaperone Nas2. J Biol Chem 2023; 299:102870. [PMID: 36621624 PMCID: PMC9922823 DOI: 10.1016/j.jbc.2023.102870] [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: 07/19/2022] [Revised: 12/21/2022] [Accepted: 12/28/2022] [Indexed: 01/07/2023] Open
Abstract
The proteasome holoenzyme is a complex molecular machine that degrades most proteins. In the proteasome holoenzyme, six distinct ATPase subunits (Rpt1 through Rpt6) enable protein degradation by injecting protein substrates into it. Individual Rpt subunits assemble into a heterohexameric "Rpt ring" in a stepwise manner, by binding to their cognate chaperones. Completion of the heterohexameric Rpt ring correlates with release of a specific chaperone, Nas2; however, it is unclear whether and how this event may ensure proper Rpt ring assembly. Here, we examined the action of Nas2 by capturing the poorly characterized penultimate step of heterohexameric Rpt ring assembly. For this, we used a heterologous Escherichia coli system coexpressing all Rpt subunits and assembly chaperones as well as Saccharomyces cerevisiae to track Nas2 actions during endogenous Rpt ring assembly. We show that Nas2 uses steric hindrance to block premature progression of the penultimate step into the final step of Rpt ring assembly. Importantly, Nas2 can activate an assembly checkpoint via its steric activity, when the last ATPase subunit, Rpt1, cannot be added in a timely manner. This checkpoint can be relieved via Nas2 release, when Nas2 recognizes proper addition of Rpt1 to one side of its cognate Rpt5, and ATP hydrolysis by Rpt4 on the other side of Rpt5, allowing completion of Rpt ring assembly. Our findings reveal dual criteria for Nas2 release, as a mechanism to ensure both the composition and functional competence of a newly assembled proteasomal ATPase, to generate the proteasome holoenzyme.
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Affiliation(s)
- Suganya Sekaran
- Department of Molecular Cellular and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA
| | - Soyeon Park
- Department of Molecular Cellular and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA.
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17
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The Ubiquitin-26S Proteasome Pathway and Its Role in the Ripening of Fleshy Fruits. Int J Mol Sci 2023; 24:ijms24032750. [PMID: 36769071 PMCID: PMC9917055 DOI: 10.3390/ijms24032750] [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: 11/26/2022] [Revised: 01/17/2023] [Accepted: 01/20/2023] [Indexed: 02/04/2023] Open
Abstract
The 26S proteasome is an ATP-dependent proteolytic complex in eukaryotes, which is mainly responsible for the degradation of damaged and misfolded proteins and some regulatory proteins in cells, and it is essential to maintain the balance of protein levels in the cell. The ubiquitin-26S proteasome pathway, which targets a wide range of protein substrates in plants, is an important post-translational regulatory mechanism involved in various stages of plant growth and development and in the maturation process of fleshy fruits. Fleshy fruit ripening is a complex biological process, which is the sum of a series of physiological and biochemical reactions, including the biosynthesis and signal transduction of ripening related hormones, pigment metabolism, fruit texture changes and the formation of nutritional quality. This paper reviews the structure of the 26S proteasome and the mechanism of the ubiquitin-26S proteasome pathway, and it summarizes the function of this pathway in the ripening process of fleshy fruits.
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18
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Yu P, Hua Z. To Kill or to Be Killed: How Does the Battle between the UPS and Autophagy Maintain the Intracellular Homeostasis in Eukaryotes? Int J Mol Sci 2023; 24:ijms24032221. [PMID: 36768543 PMCID: PMC9917186 DOI: 10.3390/ijms24032221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/18/2023] [Accepted: 01/19/2023] [Indexed: 01/27/2023] Open
Abstract
The ubiquitin-26S proteasome system and autophagy are two major protein degradation machineries encoded in all eukaryotic organisms. While the UPS is responsible for the turnover of short-lived and/or soluble misfolded proteins under normal growth conditions, the autophagy-lysosomal/vacuolar protein degradation machinery is activated under stress conditions to remove long-lived proteins in the forms of aggregates, either soluble or insoluble, in the cytoplasm and damaged organelles. Recent discoveries suggested an integrative function of these two seemly independent systems for maintaining the proteome homeostasis. One such integration is represented by their reciprocal degradation, in which the small 76-amino acid peptide, ubiquitin, plays an important role as the central signaling hub. In this review, we summarized the current knowledge about the activity control of proteasome and autophagosome at their structural organization, biophysical states, and turnover levels from yeast and mammals to plants. Through comprehensive literature studies, we presented puzzling questions that are awaiting to be solved and proposed exciting new research directions that may shed light on the molecular mechanisms underlying the biological function of protein degradation.
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Affiliation(s)
- Peifeng Yu
- Department of Environmental and Plant Biology, Ohio University, Athens, OH 45701, USA
- Interdisciplinary Program in Molecular and Cellular Biology, Ohio University, Athens, OH 45701, USA
| | - Zhihua Hua
- Department of Environmental and Plant Biology, Ohio University, Athens, OH 45701, USA
- Interdisciplinary Program in Molecular and Cellular Biology, Ohio University, Athens, OH 45701, USA
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19
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Jonsson E, Htet ZM, Bard JA, Dong KC, Martin A. Ubiquitin modulates 26 S proteasome conformational dynamics and promotes substrate degradation. SCIENCE ADVANCES 2022; 8:eadd9520. [PMID: 36563145 PMCID: PMC9788759 DOI: 10.1126/sciadv.add9520] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 10/27/2022] [Indexed: 06/17/2023]
Abstract
The 26S proteasome recognizes thousands of appropriate protein substrates in eukaryotic cells through attached ubiquitin chains and uses its adenosine triphosphatase (ATPase) motor for mechanical unfolding and translocation into a proteolytic chamber. Here, we used single-molecule Förster resonance energy transfer measurements to monitor the conformational dynamics of the proteasome, observe individual substrates during their progression toward degradation, and elucidate how these processes are regulated by ubiquitin chains. Rapid transitions between engagement- and processing-competent proteasome conformations control substrate access to the ATPase motor. Ubiquitin chain binding functions as an allosteric regulator to slow these transitions, stabilize the engagement-competent state, and aid substrate capture to accelerate degradation initiation. Upon substrate engagement, the proteasome remains in processing-competent states for translocation and unfolding, except for apparent motor slips when encountering stably folded domains. Our studies revealed how ubiquitin chains allosterically regulate degradation initiation, which ensures substrate selectivity in a crowded cellular environment.
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Affiliation(s)
- Erik Jonsson
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA
- California Institute for Quantitative Biosciences, University of California at Berkeley, Berkeley, CA 94720, USA
- Howard Hughes Medical Institute, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Zaw Min Htet
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA
- California Institute for Quantitative Biosciences, University of California at Berkeley, Berkeley, CA 94720, USA
- Howard Hughes Medical Institute, University of California at Berkeley, Berkeley, CA 94720, USA
| | | | - Ken C. Dong
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA
- California Institute for Quantitative Biosciences, University of California at Berkeley, Berkeley, CA 94720, USA
- Howard Hughes Medical Institute, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Andreas Martin
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA
- California Institute for Quantitative Biosciences, University of California at Berkeley, Berkeley, CA 94720, USA
- Howard Hughes Medical Institute, University of California at Berkeley, Berkeley, CA 94720, USA
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20
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Osei-Amponsa V, Walters KJ. Proteasome substrate receptors and their therapeutic potential. Trends Biochem Sci 2022; 47:950-964. [PMID: 35817651 PMCID: PMC9588529 DOI: 10.1016/j.tibs.2022.06.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 06/02/2022] [Accepted: 06/14/2022] [Indexed: 11/22/2022]
Abstract
The ubiquitin-proteasome system (UPS) is critical for protein quality control and regulating protein lifespans. Following ubiquitination, UPS substrates bind multidomain receptors that, in addition to ubiquitin-binding sites, contain functional domains that bind to deubiquitinating enzymes (DUBs) or the E3 ligase E6AP/UBE3A. We provide an overview of the proteasome, focusing on its receptors and DUBs. We highlight the key role of dynamics and importance of the substrate receptors having domains for both binding and processing ubiquitin chains. The UPS is rich with therapeutic opportunities, with proteasome inhibitors used clinically and ongoing development of small molecule proteolysis targeting chimeras (PROTACs) for the degradation of disease-associated proteins. We discuss the therapeutic potential of proteasome receptors, including hRpn13, for which PROTACs have been developed.
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Affiliation(s)
- Vasty Osei-Amponsa
- Protein Processing Section, Center for Structural Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Kylie J Walters
- Protein Processing Section, Center for Structural Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA.
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21
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Kudzhaev AM, Andrianova AG, Gustchina AE, Smirnov IV, Rotanova TV. ATP-Dependent Lon Proteases in the Cellular Protein Quality Control System. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2022. [DOI: 10.1134/s1068162022040136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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22
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Sakai H, Zhou Y, Miyauchi Y, Suzuki Y, Ikeno Y, Kon R, Ikarashi N, Chiba Y, Hosoe T, Kamei J. Increased 20S Proteasome Expression and the Effect of Bortezomib during Cisplatin-Induced Muscle Atrophy. Biol Pharm Bull 2022; 45:910-918. [PMID: 35786599 DOI: 10.1248/bpb.b22-00177] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Cisplatin is a chemotherapy drug used to treat a variety of cancers. Muscle loss in cancer patients is associated with increased cancer-related mortality. Previously, we suggested that cisplatin administration increases the atrophic gene expressions of ubiquitin E3 ligases, such as atrogin-1 and muscle RING finger-1 (MuRF1), which may lead to muscle atrophy. In this study, C57BL/6J mice were treated with cisplatin (3 mg/kg, intraperitoneally) or saline for 4 consecutive days. Twenty-four hours after the final injection of cisplatin, quadriceps muscles were removed from the mice. The gene expression of Psma and Psmb, which comprise the 20S proteasome, was upregulated by cisplatin administration in the quadriceps muscle of mouse. Systemic administration of cisplatin significantly reduced not only the quadriceps muscle mass but also the diameter of the myofibers. In addition, bortezomib (0.125 mg/kg, intraperitoneally) was administered 30 min before each cisplatin treatment. The co-administration of bortezomib, a proteasome inhibitor, significantly recovered the reductions in the mass of quadriceps and myofiber diameter, although it did not recover the decline in the forelimb and forepaw strength induced by cisplatin. Increased 20S proteasome abundance may play a significant role in the development of cisplatin-induced muscle atrophy. During cisplatin-induced skeletal muscle atrophy, different mechanisms may be involved between loss of muscle mass and strength. In addition, it is suggested that bortezomib has essentially no effect on cisplatin-induced muscle atrophy.
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Affiliation(s)
- Hiroyasu Sakai
- Department of Biomolecular Pharmacology, School of Pharmacy, Hoshi University
| | - Yujie Zhou
- Department of Biomolecular Pharmacology, School of Pharmacy, Hoshi University
| | - Yu Miyauchi
- Department of Biomolecular Pharmacology, School of Pharmacy, Hoshi University
| | - Yuta Suzuki
- Department of Biomolecular Pharmacology, School of Pharmacy, Hoshi University
| | - Yohei Ikeno
- Department of Biomolecular Pharmacology, School of Pharmacy, Hoshi University
| | - Risako Kon
- Department of Biomolecular Pharmacology, School of Pharmacy, Hoshi University
| | - Nobutomo Ikarashi
- Department of Biomolecular Pharmacology, School of Pharmacy, Hoshi University
| | - Yoshihiko Chiba
- Department of Physiology and Molecular Sciences, School of Pharmacy, Hoshi University
| | - Tomoo Hosoe
- Department of Biomolecular Pharmacology, School of Pharmacy, Hoshi University.,Department of Bioregulatory Science, School of Pharmacy, Hoshi University
| | - Junzo Kamei
- Department of Biomolecular Pharmacology, School of Pharmacy, Hoshi University.,Juntendo Advanced Research Institute for Health Science, Juntendo University
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23
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Structural and Functional Basis of JAMM Deubiquitinating Enzymes in Disease. Biomolecules 2022; 12:biom12070910. [PMID: 35883466 PMCID: PMC9313428 DOI: 10.3390/biom12070910] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 06/20/2022] [Accepted: 06/24/2022] [Indexed: 02/04/2023] Open
Abstract
Deubiquitinating enzymes (DUBs) are a group of proteases that are important for maintaining cell homeostasis by regulating the balance between ubiquitination and deubiquitination. As the only known metalloproteinase family of DUBs, JAB1/MPN/Mov34 metalloenzymes (JAMMs) are specifically associated with tumorigenesis and immunological and inflammatory diseases at multiple levels. The far smaller numbers and distinct catalytic mechanism of JAMMs render them attractive drug targets. Currently, several JAMM inhibitors have been successfully developed and have shown promising therapeutic efficacy. To gain greater insight into JAMMs, in this review, we focus on several key proteins in this family, including AMSH, AMSH-LP, BRCC36, Rpn11, and CSN5, and emphatically discuss their structural basis, diverse functions, catalytic mechanism, and current reported inhibitors targeting JAMMs. These advances set the stage for the exploitation of JAMMs as a target for the treatment of various diseases.
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24
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Nahar A, Sokolova V, Sekaran S, Orth JD, Park S. Assembly checkpoint of the proteasome regulatory particle is activated by coordinated actions of proteasomal ATPase chaperones. Cell Rep 2022; 39:110918. [PMID: 35675778 PMCID: PMC9214829 DOI: 10.1016/j.celrep.2022.110918] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 03/14/2022] [Accepted: 05/12/2022] [Indexed: 11/26/2022] Open
Abstract
The proteasome holoenzyme regulates the cellular proteome via degrading most proteins. In its 19-subunit regulatory particle (RP), a heterohexameric ATPase enables protein degradation by injecting protein substrates into the core peptidase. RP assembly utilizes “checkpoints,” where multiple dedicated chaperones bind to specific ATPase subunits and control the addition of other subunits. Here, we find that the RP assembly checkpoint relies on two common features of the chaperones. Individual chaperones can distinguish an RP, in which their cognate ATPase persists in the ATP-bound state. Chaperones then together modulate ATPase activity to facilitate RP subunit rearrangements for switching to an active, substrate-processing state in the resulting proteasome holoenzyme. Thus, chaperones may sense ATP binding and hydrolysis as a readout for the quality of the RP complex to generate a functional proteasome holoenzyme. Our findings provide a basis to potentially exploit the assembly checkpoints in situations with known deregulation of proteasomal ATPase chaperones. Nahar et al. report that cells build functional proteasomes by utilizing an assembly checkpoint, which is activated by a common feature of multiple dedicated chaperones; they can distinguish the nucleotide state of proteasomal ATPases and help facilitate proper subunit rearrangement to ensure efficient protein degradation by the proteasome.
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Affiliation(s)
- Asrafun Nahar
- Department of Molecular, Cellular and Developmental Biology, University of Colorado Boulder, 1945 Colorado Avenue, Boulder, CO 80309, USA
| | - Vladyslava Sokolova
- Department of Molecular, Cellular and Developmental Biology, University of Colorado Boulder, 1945 Colorado Avenue, Boulder, CO 80309, USA
| | - Suganya Sekaran
- Department of Molecular, Cellular and Developmental Biology, University of Colorado Boulder, 1945 Colorado Avenue, Boulder, CO 80309, USA
| | - James D Orth
- Department of Molecular, Cellular and Developmental Biology, University of Colorado Boulder, 1945 Colorado Avenue, Boulder, CO 80309, USA
| | - Soyeon Park
- Department of Molecular, Cellular and Developmental Biology, University of Colorado Boulder, 1945 Colorado Avenue, Boulder, CO 80309, USA.
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25
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Li YC, Wang Y, Zou W. Exploration on the Mechanism of Ubiquitin Proteasome System in Cerebral Stroke. Front Aging Neurosci 2022; 14:814463. [PMID: 35462700 PMCID: PMC9022456 DOI: 10.3389/fnagi.2022.814463] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Accepted: 03/14/2022] [Indexed: 12/23/2022] Open
Abstract
Stroke’s secondary damage, such as inflammation, oxidative stress, and mitochondrial dysfunction, are thought to be crucial factors in the disease’s progression. Despite the fact that there are numerous treatments for secondary damage following stroke, such as antiplatelet therapy, anticoagulant therapy, surgery, and so on, the results are disappointing and the side effects are numerous. It is critical to develop novel and effective strategies for improving patient prognosis. The ubiquitin proteasome system (UPS) is the hub for the processing and metabolism of a wide range of functional regulatory proteins in cells. It is critical for the maintenance of cell homeostasis. With the advancement of UPS research in recent years, it has been discovered that UPS is engaged in a variety of physiological and pathological processes in the human body. UPS is expected to play a role in the onset and progression of stroke via multiple targets and pathways. This paper explores the method by which UPS participates in the linked pathogenic process following stroke, in order to give a theoretical foundation for further research into UPS and stroke treatment.
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Affiliation(s)
- Yu-Chao Li
- Heilongjiang University of Chinese Medicine, Harbin, China
| | - Yan Wang
- School of Traditional Chinese Medicine, Ningxia Medical University, Yinchuan, China
| | - Wei Zou
- Heilongjiang University of Chinese Medicine, Harbin, China
- First Affiliated Hospital, Heilongjiang University of Chinese Medicine, Harbin, China
- *Correspondence: Wei Zou,
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26
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Lee HJ, Lee DM, Seo MJ, Kang HC, Kwon SK, Choi KS. PSMD14 Targeting Triggers Paraptosis in Breast Cancer Cells by Inducing Proteasome Inhibition and Ca 2+ Imbalance. Int J Mol Sci 2022; 23:ijms23052648. [PMID: 35269789 PMCID: PMC8910635 DOI: 10.3390/ijms23052648] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 02/23/2022] [Accepted: 02/25/2022] [Indexed: 02/06/2023] Open
Abstract
PSMD14, a subunit of the 19S regulatory particles of the 26S proteasome, was recently identified as a potential prognostic marker and therapeutic target in diverse human cancers. Here, we show that the silencing and pharmacological blockade of PSMD14 in MDA-MB 435S breast cancer cells induce paraptosis, a non-apoptotic cell death mode characterized by extensive vacuolation derived from the endoplasmic reticulum (ER) and mitochondria. The PSMD14 inhibitor, capzimin (CZM), inhibits proteasome activity but differs from the 20S proteasome subunit-inhibiting bortezomib (Bz) in that it does not induce aggresome formation or Nrf1 upregulation, which underlie Bz resistance in cancer cells. In addition to proteasome inhibition, the release of Ca2+ from the ER into the cytosol critically contributes to CZM-induced paraptosis. Induction of paraptosis by targeting PSMD14 may provide an attractive therapeutic strategy against cancer cells resistant to proteasome inhibitors or pro-apoptotic drugs.
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Affiliation(s)
- Hong-Jae Lee
- Department of Biochemistry and Molecular Biology, Ajou University, Suwon 16499, Korea; (H.-J.L.); (D.-M.L.); (M.-J.S.)
| | - Dong-Min Lee
- Department of Biochemistry and Molecular Biology, Ajou University, Suwon 16499, Korea; (H.-J.L.); (D.-M.L.); (M.-J.S.)
| | - Min-Ji Seo
- Department of Biochemistry and Molecular Biology, Ajou University, Suwon 16499, Korea; (H.-J.L.); (D.-M.L.); (M.-J.S.)
| | - Ho-Chul Kang
- Department of Physiology, Ajou University School of Medicine, Suwon 16499, Korea;
| | - Seok-Kyu Kwon
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea;
- Division of Bio-Medical Science & Technology, KIST School, Korea University of Science & Technology (UST), Daejeon 34113, Korea
| | - Kyeong-Sook Choi
- Department of Biochemistry and Molecular Biology, Ajou University, Suwon 16499, Korea; (H.-J.L.); (D.-M.L.); (M.-J.S.)
- Correspondence: ; Tel.: +82-31-219-4552; Fax: +82-31-219-5059
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27
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Hung KYS, Klumpe S, Eisele MR, Elsasser S, Tian G, Sun S, Moroco JA, Cheng TC, Joshi T, Seibel T, Van Dalen D, Feng XH, Lu Y, Ovaa H, Engen JR, Lee BH, Rudack T, Sakata E, Finley D. Allosteric control of Ubp6 and the proteasome via a bidirectional switch. Nat Commun 2022; 13:838. [PMID: 35149681 PMCID: PMC8837689 DOI: 10.1038/s41467-022-28186-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Accepted: 01/10/2022] [Indexed: 11/09/2022] Open
Abstract
The proteasome recognizes ubiquitinated proteins and can also edit ubiquitin marks, allowing substrates to be rejected based on ubiquitin chain topology. In yeast, editing is mediated by deubiquitinating enzyme Ubp6. The proteasome activates Ubp6, whereas Ubp6 inhibits the proteasome through deubiquitination and a noncatalytic effect. Here, we report cryo-EM structures of the proteasome bound to Ubp6, based on which we identify mutants in Ubp6 and proteasome subunit Rpt1 that abrogate Ubp6 activation. The Ubp6 mutations define a conserved region that we term the ILR element. The ILR is found within the BL1 loop, which obstructs the catalytic groove in free Ubp6. Rpt1-ILR interaction opens the groove by rearranging not only BL1 but also a previously undescribed network of three interconnected active-site-blocking loops. Ubp6 activation and noncatalytic proteasome inhibition are linked in that they are eliminated by the same mutations. Ubp6 and ubiquitin together drive proteasomes into a unique conformation associated with proteasome inhibition. Thus, a multicomponent allosteric switch exerts simultaneous control over both Ubp6 and the proteasome.
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Affiliation(s)
| | - Sven Klumpe
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152, Martinsried, Germany
| | - Markus R Eisele
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152, Martinsried, Germany
| | - Suzanne Elsasser
- Department of Cell Biology, Harvard Medical School, Boston, MA, 02115, USA
| | - Geng Tian
- Department of Cell Biology, Harvard Medical School, Boston, MA, 02115, USA
| | - Shuangwu Sun
- Department of Cell Biology, Harvard Medical School, Boston, MA, 02115, USA.,Life Sciences Institute (LSI), Zhejiang University, Hangzhou, 310058, China
| | - Jamie A Moroco
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, 02115, USA
| | - Tat Cheung Cheng
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152, Martinsried, Germany.,Institute for Auditory Neuroscience, University Medical Center Göttingen, 37077, Göttingen, Germany
| | - Tapan Joshi
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152, Martinsried, Germany
| | - Timo Seibel
- Department of Cell Biology, Harvard Medical School, Boston, MA, 02115, USA
| | - Duco Van Dalen
- Leiden University Medical Center, Einthovenweg 20, 2333, Leiden, ZC, the Netherlands
| | - Xin-Hua Feng
- Life Sciences Institute (LSI), Zhejiang University, Hangzhou, 310058, China
| | - Ying Lu
- Department of Systems Biology, Harvard Medical School, Boston, MA, 02115, USA
| | - Huib Ovaa
- Leiden University Medical Center, Einthovenweg 20, 2333, Leiden, ZC, the Netherlands
| | - John R Engen
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, 02115, USA
| | - Byung-Hoon Lee
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Korea.
| | - Till Rudack
- Biospectroscopy, Center for Protein Diagnostics (PRODI), Ruhr University Bochum, 44801, Bochum, Germany. .,Department of Biophysics, Ruhr University Bochum, 44801, Bochum, Germany.
| | - Eri Sakata
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152, Martinsried, Germany. .,Institute for Auditory Neuroscience, University Medical Center Göttingen, 37077, Göttingen, Germany. .,Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells (MBExC), University of Goettingen, 37073, Göttingen, Germany.
| | - Daniel Finley
- Department of Cell Biology, Harvard Medical School, Boston, MA, 02115, USA.
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28
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Functional Differences between Proteasome Subtypes. Cells 2022; 11:cells11030421. [PMID: 35159231 PMCID: PMC8834425 DOI: 10.3390/cells11030421] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/11/2022] [Accepted: 01/14/2022] [Indexed: 12/30/2022] Open
Abstract
Four proteasome subtypes are commonly present in mammalian tissues: standard proteasomes, which contain the standard catalytic subunits β1, β2 and β5; immunoproteasomes containing the immuno-subunits β1i, β2i and β5i; and two intermediate proteasomes, containing a mix of standard and immuno-subunits. Recent studies revealed the expression of two tissue-specific proteasome subtypes in cortical thymic epithelial cells and in testes: thymoproteasomes and spermatoproteasomes. In this review, we describe the mechanisms that enable the ATP- and ubiquitin-dependent as well as the ATP- and ubiquitin-independent degradation of proteins by the proteasome. We focus on understanding the role of the different proteasome subtypes in maintaining protein homeostasis in normal physiological conditions through the ATP- and ubiquitin-dependent degradation of proteins. Additionally, we discuss the role of each proteasome subtype in the ATP- and ubiquitin-independent degradation of disordered proteins. We also discuss the role of the proteasome in the generation of peptides presented by MHC class I molecules and the implication of having different proteasome subtypes for the peptide repertoire presented at the cell surface. Finally, we discuss the role of the immunoproteasome in immune cells and its modulation as a potential therapy for autoimmune diseases.
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29
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Chen X, Htet ZM, López-Alfonzo E, Martin A, Walters KJ. Proteasome interaction with ubiquitinated substrates: from mechanisms to therapies. FEBS J 2021; 288:5231-5251. [PMID: 33211406 PMCID: PMC8131406 DOI: 10.1111/febs.15638] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 11/10/2020] [Accepted: 11/17/2020] [Indexed: 12/11/2022]
Abstract
The 26S proteasome is responsible for regulated proteolysis in eukaryotic cells. Its substrates are diverse in structure, function, sequence length, and amino acid composition, and are targeted to the proteasome by post-translational modification with ubiquitin. Ubiquitination occurs through a complex enzymatic cascade and can also signal for other cellular events, unrelated to proteasome-catalyzed degradation. Like other post-translational protein modifications, ubiquitination is reversible, with ubiquitin chain hydrolysis catalyzed by the action of deubiquitinating enzymes (DUBs), ~ 90 of which exist in humans and allow for temporal events and dynamic ubiquitin-chain remodeling. DUBs have been known for decades to be an integral part of the proteasome, as deubiquitination is coupled to substrate unfolding and translocation into the internal degradation chamber. Moreover, the proteasome also binds several ubiquitinating enzymes and shuttle factors that recruit ubiquitinated substrates. The role of this intricate machinery and how ubiquitinated substrates interact with proteasomes remains an area of active investigation. Here, we review what has been learned about the mechanisms used by the proteasome to bind ubiquitinated substrates, substrate shuttle factors, ubiquitination machinery, and DUBs. We also discuss many open questions that require further study or the development of innovative approaches to be answered. Finally, we address the promise of expanded therapeutic targeting that could benefit from such new discoveries.
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Affiliation(s)
- Xiang Chen
- Protein Processing Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD, USA
| | - Zaw Min Htet
- Department of Molecular and Cell Biology, California Institute for Quantitative Biosciences, University of California at Berkeley, CA, USA
| | - Erika López-Alfonzo
- Department of Molecular and Cell Biology, California Institute for Quantitative Biosciences, University of California at Berkeley, CA, USA
| | - Andreas Martin
- Department of Molecular and Cell Biology, California Institute for Quantitative Biosciences, University of California at Berkeley, CA, USA
- Howard Hughes Medical Institute, University of California at Berkeley, CA, USA
| | - Kylie J Walters
- Protein Processing Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD, USA
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30
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Dederer V, Lemberg MK. Transmembrane dislocases: a second chance for protein targeting. Trends Cell Biol 2021; 31:898-911. [PMID: 34147299 DOI: 10.1016/j.tcb.2021.05.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 05/11/2021] [Accepted: 05/14/2021] [Indexed: 12/31/2022]
Abstract
Precise distribution of proteins is essential to sustain the viability of cells. A complex network of protein synthesis and targeting factors cooperate with protein quality control systems to ensure protein homeostasis. Defective proteins are inevitably degraded by the ubiquitin-proteasome system and lysosomes. However, due to overlapping targeting information and limited targeting fidelity, certain proteins become mislocalized. In this review, we present the idea that transmembrane dislocases recognize and remove mislocalized membrane proteins from cellular organelles. This enables other targeting attempts and prevents degradation of mislocalized but otherwise functional proteins. These transmembrane dislocases can be found in the outer mitochondrial membrane (OMM) and endoplasmic reticulum (ER). We highlight common principles regarding client recognition and outline open questions in our understanding of transmembrane dislocases.
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Affiliation(s)
- Verena Dederer
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany; Current address: Institute for Pharmaceutical Biology and Buchmann Institute for Molecular Life Science, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Marius K Lemberg
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany; Center for Biochemistry, Medical Faculty, University of Cologne, 50931 Cologne, Germany.
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31
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Creekmore BC, Chang YW, Lee EB. The Cryo-EM Effect: Structural Biology of Neurodegenerative Disease Proteostasis Factors. J Neuropathol Exp Neurol 2021; 80:494-513. [PMID: 33860329 PMCID: PMC8177850 DOI: 10.1093/jnen/nlab029] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Neurodegenerative diseases are characterized by the accumulation of misfolded proteins. This protein aggregation suggests that abnormal proteostasis contributes to aging-related neurodegeneration. A better fundamental understanding of proteins that regulate proteostasis may provide insight into the pathophysiology of neurodegenerative disease and may perhaps reveal novel therapeutic opportunities. The 26S proteasome is the key effector of the ubiquitin-proteasome system responsible for degrading polyubiquitinated proteins. However, additional factors, such as valosin-containing protein (VCP/p97/Cdc48) and C9orf72, play a role in regulation and trafficking of substrates through the normal proteostasis systems of a cell. Nonhuman AAA+ ATPases, such as the disaggregase Hsp104, also provide insights into the biochemical processes that regulate protein aggregation. X-ray crystallography and cryo-electron microscopy (cryo-EM) structures not bound to substrate have provided meaningful information about the 26S proteasome, VCP, and Hsp104. However, recent cryo-EM structures bound to substrate have provided new information about the function and mechanism of these proteostasis factors. Cryo-EM and cryo-electron tomography data combined with biochemical data have also increased the understanding of C9orf72 and its role in maintaining proteostasis. These structural insights provide a foundation for understanding proteostasis mechanisms with near-atomic resolution upon which insights can be gleaned regarding the pathophysiology of neurodegenerative diseases.
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Affiliation(s)
- Benjamin C Creekmore
- From the Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Graduate Program in Biochemistry and Molecular Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Translational Neuropathology Research Laboratory, Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Yi-Wei Chang
- From the Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Edward B Lee
- Translational Neuropathology Research Laboratory, Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
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32
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Altered Phosphorylation of the Proteasome Subunit Rpt6 Has Minimal Impact on Synaptic Plasticity and Learning. eNeuro 2021; 8:ENEURO.0073-20.2021. [PMID: 33658307 PMCID: PMC8116113 DOI: 10.1523/eneuro.0073-20.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 01/13/2021] [Accepted: 01/27/2021] [Indexed: 11/21/2022] Open
Abstract
Dynamic control of protein degradation via the ubiquitin proteasome system (UPS) is thought to play a crucial role in neuronal function and synaptic plasticity. The proteasome subunit Rpt6, an AAA ATPase subunit of the 19S regulatory particle (RP), has emerged as an important site for regulation of 26S proteasome function in neurons. Phosphorylation of Rpt6 on serine 120 (S120) can stimulate the catalytic rate of substrate degradation by the 26S proteasome and this site is targeted by the plasticity-related kinase Ca2+/calmodulin-dependent kinase II (CaMKII), making it an attractive candidate for regulation of proteasome function in neurons. Several in vitro studies have shown that altered Rpt6 S120 phosphorylation can affect the structure and function of synapses. To evaluate the importance of Rpt6 S120 phosphorylation in vivo, we created two mouse models which feature mutations at S120 that block or mimic phosphorylation at this site. We find that peptidase and ATPase activities are upregulated in the phospho-mimetic mutant and downregulated in the phospho-dead mutant [S120 mutated to aspartic acid (S120D) or alanine (S120A), respectively]. Surprisingly, these mutations had no effect on basal synaptic transmission, long-term potentiation (LTP), and dendritic spine dynamics and density in the hippocampus. Furthermore, these mutants displayed no deficits in cued and contextual fear memory. Thus, in a mouse model that blocks or mimics phosphorylation at this site, either compensatory mechanisms negate these effects, or small variations in proteasome activity are not enough to induce significant changes in synaptic structure, plasticity, or behavior.
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33
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Aliabadi F, Sohrabi B, Mostafavi E, Pazoki-Toroudi H, Webster TJ. Ubiquitin-proteasome system and the role of its inhibitors in cancer therapy. Open Biol 2021; 11:200390. [PMID: 33906413 PMCID: PMC8080017 DOI: 10.1098/rsob.200390] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Despite all the other cells that have the potential to prevent cancer development and metastasis through tumour suppressor proteins, cancer cells can upregulate the ubiquitin–proteasome system (UPS) by which they can degrade tumour suppressor proteins and avoid apoptosis. This system plays an extensive role in cell regulation organized in two steps. Each step has an important role in controlling cancer. This demonstrates the importance of understanding UPS inhibitors and improving these inhibitors to foster a new hope in cancer therapy. UPS inhibitors, as less invasive chemotherapy drugs, are increasingly used to alleviate symptoms of various cancers in malignant states. Despite their success in reducing the development of cancer with the lowest side effects, thus far, an appropriate inhibitor that can effectively inactivate this system with the least drug resistance has not yet been fully investigated. A fundamental understanding of the system is necessary to fully elucidate its role in causing/controlling cancer. In this review, we first comprehensively investigate this system, and then each step containing ubiquitination and protein degradation as well as their inhibitors are discussed. Ultimately, its advantages and disadvantages and some perspectives for improving the efficiency of these inhibitors are discussed.
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Affiliation(s)
- Fatemeh Aliabadi
- Physiology Research Center, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Beheshteh Sohrabi
- Department of Chemistry, Surface Chemistry Research Laboratory, Iran University of Science and Technology, PO Box 16846-13114, Tehran, Iran
| | - Ebrahim Mostafavi
- Department of Chemical Engineering, Northeastern University, Boston, MA 02115, USA.,Stanford Cardiovascular Institute, Stanford, CA, USA.,Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Hamidreza Pazoki-Toroudi
- Physiology Research Center, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran.,Department of Physiology, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Thomas J Webster
- Department of Chemical Engineering, Northeastern University, Boston, MA 02115, USA
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34
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The proteasome and its role in the nervous system. Cell Chem Biol 2021; 28:903-917. [PMID: 33905676 DOI: 10.1016/j.chembiol.2021.04.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 03/04/2021] [Accepted: 04/05/2021] [Indexed: 12/14/2022]
Abstract
Proteasomes are multisubunit complexes that catalyze the majority of protein degradation in mammalian cells to maintain protein homeostasis and influence the regulation of most cellular processes. The proteasome, a multicatalytic protease complex, is a ring-like structure with a narrow pore that exhibits regulated gating, enabling the selective degradation of target proteins into peptide fragments. This process of removing proteins is essential for eliminating proteins that are no longer wanted, such as unfolded or aggregated proteins. This is important for preserving cellular function relevant to brain health and disease. Recently, in the nervous system, specialized proteasomes have been shown to generate peptides with important cellular functions. These discoveries challenge the prevailing notion that proteasomes primarily operate to eliminate proteins and identify signaling-competent proteasomes. This review focuses on the structure, function, and regulation of proteasomes and sheds light on emerging areas of investigation regarding the role of proteasomes in the nervous system.
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35
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Davis C, Spaller BL, Matouschek A. Mechanisms of substrate recognition by the 26S proteasome. Curr Opin Struct Biol 2021; 67:161-169. [PMID: 33296738 PMCID: PMC8096638 DOI: 10.1016/j.sbi.2020.10.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 10/12/2020] [Accepted: 10/15/2020] [Indexed: 02/08/2023]
Abstract
The majority of regulated protein degradation in eukaryotes is accomplished by the 26S proteasome, the large proteolytic complex responsible for removing regulatory proteins and damaged proteins. Proteins are targeted to the proteasome by ubiquitination, and degradation is initiated at a disordered region within the protein. The ability of the proteasome to precisely select which proteins to break down is necessary for cellular functioning. Recent studies reveal the subtle mechanisms of substrate recognition by the proteasome - diverse ubiquitin chains can act as potent proteasome targeting signals, ubiquitin receptors function uniquely and cooperatively, and modification of initiation regions modulate degradation. Here, we summarize recent findings illuminating the nature of substrate recognition by the proteasome.
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Affiliation(s)
- Caroline Davis
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Brian Logan Spaller
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Andreas Matouschek
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA.
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36
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Proteasome in action: substrate degradation by the 26S proteasome. Biochem Soc Trans 2021; 49:629-644. [PMID: 33729481 PMCID: PMC8106498 DOI: 10.1042/bst20200382] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/22/2021] [Accepted: 02/25/2021] [Indexed: 12/16/2022]
Abstract
Ubiquitination is the major criteria for the recognition of a substrate-protein by the 26S proteasome. Additionally, a disordered segment on the substrate — either intrinsic or induced — is critical for proteasome engagement. The proteasome is geared to interact with both of these substrate features and prepare it for degradation. To facilitate substrate accessibility, resting proteasomes are characterised by a peripheral distribution of ubiquitin receptors on the 19S regulatory particle (RP) and a wide-open lateral surface on the ATPase ring. In this substrate accepting state, the internal channel through the ATPase ring is discontinuous, thereby obstructing translocation of potential substrates. The binding of the conjugated ubiquitin to the ubiquitin receptors leads to contraction of the 19S RP. Next, the ATPases engage the substrate at a disordered segment, energetically unravel the polypeptide and translocate it towards the 20S catalytic core (CP). In this substrate engaged state, Rpn11 is repositioned at the pore of the ATPase channel to remove remaining ubiquitin modifications and accelerate translocation. C-termini of five of the six ATPases insert into corresponding lysine-pockets on the 20S α-ring to complete 20S CP gate opening. In the resulting substrate processing state, the ATPase channel is fully contiguous with the translocation channel into the 20S CP, where the substrate is proteolyzed. Complete degradation of a typical ubiquitin-conjugate takes place over a few tens of seconds while hydrolysing tens of ATP molecules in the process (50 kDa/∼50 s/∼80ATP). This article reviews recent insight into biochemical and structural features that underlie substrate recognition and processing by the 26S proteasome.
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37
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Kudriaeva AA, Livneh I, Baranov MS, Ziganshin RH, Tupikin AE, Zaitseva SO, Kabilov MR, Ciechanover A, Belogurov AA. In-depth characterization of ubiquitin turnover in mammalian cells by fluorescence tracking. Cell Chem Biol 2021; 28:1192-1205.e9. [PMID: 33675681 DOI: 10.1016/j.chembiol.2021.02.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 12/29/2020] [Accepted: 02/11/2021] [Indexed: 01/01/2023]
Abstract
Despite almost 40 years having passed from the initial discovery of ubiquitin (Ub), fundamental questions related to its intracellular metabolism are still enigmatic. Here we utilized fluorescent tracking for monitoring ubiquitin turnover in mammalian cells, resulting in obtaining qualitatively new data. In the present study we report (1) short Ub half-life estimated as 4 h; (2) for a median of six Ub molecules per substrate as a dynamic equilibrium between Ub ligases and deubiquitinated enzymes (DUBs); (3) loss on average of one Ub molecule per four acts of engagement of polyubiquitinated substrate by the proteasome; (4) direct correlation between incorporation of Ub into the distinct type of chains and Ub half-life; and (5) critical influence of the single lysine residue K27 on the stability of the whole Ub molecule. Concluding, our data provide a comprehensive understanding of ubiquitin-proteasome system dynamics on the previously unreachable state of the art.
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Affiliation(s)
- Anna A Kudriaeva
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997 Moscow, Russian Federation
| | - Ido Livneh
- Technion Integrated Cancer Center, The Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, 3109602 Haifa, Israel
| | - Mikhail S Baranov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997 Moscow, Russian Federation; Pirogov Russian National Research Medical University, Ostrovitianov 1, 117997 Moscow, Russian Federation
| | - Rustam H Ziganshin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997 Moscow, Russian Federation
| | - Alexey E Tupikin
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Lavrentieva 8, 630090 Novosibirsk, Russian Federation
| | - Snizhana O Zaitseva
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997 Moscow, Russian Federation
| | - Marsel R Kabilov
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Lavrentieva 8, 630090 Novosibirsk, Russian Federation
| | - Aaron Ciechanover
- Technion Integrated Cancer Center, The Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, 3109602 Haifa, Israel
| | - Alexey A Belogurov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997 Moscow, Russian Federation; Lomonosov Moscow State University, Leninskie Gory, 119991 Moscow, Russian Federation.
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Abstract
The 26S proteasome is the most complex ATP-dependent protease machinery, of ~2.5 MDa mass, ubiquitously found in all eukaryotes. It selectively degrades ubiquitin-conjugated proteins and plays fundamentally indispensable roles in regulating almost all major aspects of cellular activities. To serve as the sole terminal "processor" for myriad ubiquitylation pathways, the proteasome evolved exceptional adaptability in dynamically organizing a large network of proteins, including ubiquitin receptors, shuttle factors, deubiquitinases, AAA-ATPase unfoldases, and ubiquitin ligases, to enable substrate selectivity and processing efficiency and to achieve regulation precision of a vast diversity of substrates. The inner working of the 26S proteasome is among the most sophisticated, enigmatic mechanisms of enzyme machinery in eukaryotic cells. Recent breakthroughs in three-dimensional atomic-level visualization of the 26S proteasome dynamics during polyubiquitylated substrate degradation elucidated an extensively detailed picture of its functional mechanisms, owing to progressive methodological advances associated with cryogenic electron microscopy (cryo-EM). Multiple sites of ubiquitin binding in the proteasome revealed a canonical mode of ubiquitin-dependent substrate engagement. The proteasome conformation in the act of substrate deubiquitylation provided insights into how the deubiquitylating activity of RPN11 is enhanced in the holoenzyme and is coupled to substrate translocation. Intriguingly, three principal modes of coordinated ATP hydrolysis in the heterohexameric AAA-ATPase motor were discovered to regulate intermediate functional steps of the proteasome, including ubiquitin-substrate engagement, deubiquitylation, initiation of substrate translocation and processive substrate degradation. The atomic dissection of the innermost working of the 26S proteasome opens up a new era in our understanding of the ubiquitin-proteasome system and has far-reaching implications in health and disease.
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Affiliation(s)
- Youdong Mao
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, 02215, Massachusetts, USA. .,School of Physics, Center for Quantitative Biology, Peking University, Beijing, 100871, China.
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Molecular and cellular dynamics of the 26S proteasome. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2020; 1869:140583. [PMID: 33321258 DOI: 10.1016/j.bbapap.2020.140583] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 12/07/2020] [Accepted: 12/09/2020] [Indexed: 01/16/2023]
Abstract
In eukaryotic cells, the ubiquitin-proteasome system serves to remove proteins that are either dysfunctional or no longer needed. The 26S proteasome is a 2.5 MDa multisubunit complex comprising the 20S core particle, where degradation is executed, and one or two regulatory particles which prepare substrates for degradation. Whereas the 20S core particles of several species had been studied extensively by X-ray crystallography, the 26S holocomplex structure had remained elusive for a long time. Recent advances in single-particle cryo-electron microscopy have changed the situation and provided atomic resolution models of this intriguing molecular machine and its dynamics. Besides, cryo-electron tomography enables structural studies in situ, providing molecular resolution images of macromolecules inside pristinely preserved cellular environments. This has greatly contributed to our understanding of proteasome dynamics in the context of cells.
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Peck Justice SA, Barron MP, Qi GD, Wijeratne HRS, Victorino JF, Simpson ER, Vilseck JZ, Wijeratne AB, Mosley AL. Mutant thermal proteome profiling for characterization of missense protein variants and their associated phenotypes within the proteome. J Biol Chem 2020; 295:16219-16238. [PMID: 32878984 PMCID: PMC7705321 DOI: 10.1074/jbc.ra120.014576] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 08/17/2020] [Indexed: 12/20/2022] Open
Abstract
Temperature-sensitive (TS) missense mutants have been foundational for characterization of essential gene function. However, an unbiased approach for analysis of biochemical and biophysical changes in TS missense mutants within the context of their functional proteomes is lacking. We applied MS-based thermal proteome profiling (TPP) to investigate the proteome-wide effects of missense mutations in an application that we refer to as mutant thermal proteome profiling (mTPP). This study characterized global impacts of temperature sensitivity-inducing missense mutations in two different subunits of the 26S proteasome. The majority of alterations identified by RNA-Seq and global proteomics were similar between the mutants, which could suggest that a similar functional disruption is occurring in both missense variants. Results from mTPP, however, provide unique insights into the mechanisms that contribute to the TS phenotype in each mutant, revealing distinct changes that were not obtained using only steady-state transcriptome and proteome analyses. Computationally, multisite λ-dynamics simulations add clear support for mTPP experimental findings. This work shows that mTPP is a precise approach to measure changes in missense mutant-containing proteomes without the requirement for large amounts of starting material, specific antibodies against proteins of interest, and/or genetic manipulation of the biological system. Although experiments were performed under permissive conditions, mTPP provided insights into the underlying protein stability changes that cause dramatic cellular phenotypes observed at nonpermissive temperatures. Overall, mTPP provides unique mechanistic insights into missense mutation dysfunction and connection of genotype to phenotype in a rapid, nonbiased fashion.
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Affiliation(s)
- Sarah A Peck Justice
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Monica P Barron
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA; Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Guihong D Qi
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - H R Sagara Wijeratne
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - José F Victorino
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Ed R Simpson
- Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, Indiana, USA; Department of BioHealth Informatics, School of Informatics and Computing, Indiana University-Purdue University, Indianapolis, Indiana, USA; Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Jonah Z Vilseck
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA; Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Aruna B Wijeratne
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA.
| | - Amber L Mosley
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA; Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, Indiana, USA.
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Chen X, Dorris Z, Shi D, Huang RK, Khant H, Fox T, de Val N, Williams D, Zhang P, Walters KJ. Cryo-EM Reveals Unanchored M1-Ubiquitin Chain Binding at hRpn11 of the 26S Proteasome. Structure 2020; 28:1206-1217.e4. [PMID: 32783951 PMCID: PMC7642156 DOI: 10.1016/j.str.2020.07.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 07/06/2020] [Accepted: 07/22/2020] [Indexed: 12/17/2022]
Abstract
The 26S proteasome is specialized for regulated protein degradation and formed by a dynamic regulatory particle (RP) that caps a hollow cylindrical core particle (CP) where substrates are proteolyzed. Its diverse substrates unify as proteasome targets by ubiquitination. We used cryogenic electron microscopy (cryo-EM) to study how human 26S proteasome interacts with M1-linked hexaubiquitin (M1-Ub6) unanchored to a substrate and E3 ubiquitin ligase E6AP/UBE3A. Proteasome structures are available with model substrates extending through the RP ATPase ring and substrate-conjugated K63-linked ubiquitin chains present at inhibited deubiquitinating enzyme hRpn11 and the nearby ATPase hRpt4/hRpt5 coiled coil. In this study, we find M1-Ub6 at the hRpn11 site despite the absence of conjugated substrate, indicating that ubiquitin binding at this location does not require substrate interaction with the RP. Moreover, unanchored M1-Ub6 binds to this hRpn11 site of the proteasome with the CP gating residues in both the closed and opened conformational states.
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Affiliation(s)
- Xiang Chen
- Protein Processing Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Zachary Dorris
- Protein Processing Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA; Frederick High School, Frederick, MD 21702, USA
| | - Dan Shi
- Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Rick K Huang
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
| | - Htet Khant
- Center for Molecular Microscopy, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA; Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research Inc, Frederick, MD 21701, USA
| | - Tara Fox
- Center for Molecular Microscopy, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA; Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research Inc, Frederick, MD 21701, USA
| | - Natalia de Val
- Center for Molecular Microscopy, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA; Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research Inc, Frederick, MD 21701, USA
| | - Dewight Williams
- John M. Cowley Center for High Resolution Electron Microscopy, Arizona State University, Tempe, AZ 85287, USA
| | - Ping Zhang
- Kinase Complexes Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Kylie J Walters
- Protein Processing Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA.
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42
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Efficiency of the four proteasome subtypes to degrade ubiquitinated or oxidized proteins. Sci Rep 2020; 10:15765. [PMID: 32978409 PMCID: PMC7519072 DOI: 10.1038/s41598-020-71550-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 08/19/2020] [Indexed: 01/22/2023] Open
Abstract
The proteasome is responsible for selective degradation of proteins. It exists in mammalian cells under four main subtypes, which differ by the combination of their catalytic subunits: the standard proteasome (β1–β2–β5), the immunoproteasome (β1i–β2i–β5i) and the two intermediate proteasomes (β1–β2–β5i and β1i–β2–β5i). The efficiency of the four proteasome subtypes to degrade ubiquitinated or oxidized proteins remains unclear. Using cells expressing exclusively one proteasome subtype, we observed that ubiquitinated p21 and c-myc were degraded at similar rates, indicating that the four 26S proteasomes degrade ubiquitinated proteins equally well. Under oxidative stress, we observed a partial dissociation of 26S into 20S proteasomes, which can degrade non-ubiquitinated oxidized proteins. Oxidized calmodulin and hemoglobin were best degraded in vitro by the three β5i-containing 20S proteasomes, while their native forms were not degraded. Circular dichroism analyses indicated that ubiquitin-independent recognition of oxidized proteins by 20S proteasomes was triggered by the disruption of their structure. Accordingly, β5i-containing 20S proteasomes degraded unoxidized naturally disordered protein tau, while 26S proteasomes did not. Our results suggest that the three β5i-containing 20S proteasomes, namely the immunoproteasome and the two intermediate proteasomes, might help cells to eliminate proteins containing disordered domains, including those induced by oxidative stress.
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43
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Avestan MS, Javidi A, Ganote LP, Brown JM, Stan G. Kinetic effects in directional proteasomal degradation of the green fluorescent protein. J Chem Phys 2020; 153:105101. [DOI: 10.1063/5.0015191] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Affiliation(s)
| | - Alex Javidi
- Data Sciences, Janssen Research and Development, Spring House, Pennsylvania 19477, USA
| | | | | | - George Stan
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, USA
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44
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Tundo GR, Sbardella D, Santoro AM, Coletta A, Oddone F, Grasso G, Milardi D, Lacal PM, Marini S, Purrello R, Graziani G, Coletta M. The proteasome as a druggable target with multiple therapeutic potentialities: Cutting and non-cutting edges. Pharmacol Ther 2020; 213:107579. [PMID: 32442437 PMCID: PMC7236745 DOI: 10.1016/j.pharmthera.2020.107579] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 05/05/2020] [Indexed: 01/10/2023]
Abstract
Ubiquitin Proteasome System (UPS) is an adaptable and finely tuned system that sustains proteostasis network under a large variety of physiopathological conditions. Its dysregulation is often associated with the onset and progression of human diseases; hence, UPS modulation has emerged as a promising new avenue for the development of treatments of several relevant pathologies, such as cancer and neurodegeneration. The clinical interest in proteasome inhibition has considerably increased after the FDA approval in 2003 of bortezomib for relapsed/refractory multiple myeloma, which is now used in the front-line setting. Thereafter, two other proteasome inhibitors (carfilzomib and ixazomib), designed to overcome resistance to bortezomib, have been approved for treatment-experienced patients, and a variety of novel inhibitors are currently under preclinical and clinical investigation not only for haematological malignancies but also for solid tumours. However, since UPS collapse leads to toxic misfolded proteins accumulation, proteasome is attracting even more interest as a target for the care of neurodegenerative diseases, which are sustained by UPS impairment. Thus, conceptually, proteasome activation represents an innovative and largely unexplored target for drug development. According to a multidisciplinary approach, spanning from chemistry, biochemistry, molecular biology to pharmacology, this review will summarize the most recent available literature regarding different aspects of proteasome biology, focusing on structure, function and regulation of proteasome in physiological and pathological processes, mostly cancer and neurodegenerative diseases, connecting biochemical features and clinical studies of proteasome targeting drugs.
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Affiliation(s)
- G R Tundo
- Department of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, Rome, Italy.
| | | | - A M Santoro
- CNR, Institute of Crystallography, Catania, Italy
| | - A Coletta
- Department of Chemistry, University of Aarhus, Aarhus, Denmark
| | - F Oddone
- IRCCS-Fondazione Bietti, Rome, Italy
| | - G Grasso
- Department of Chemical Sciences, University of Catania, Catania, Italy
| | - D Milardi
- CNR, Institute of Crystallography, Catania, Italy
| | - P M Lacal
- Laboratory of Molecular Oncology, IDI-IRCCS, Rome, Italy
| | - S Marini
- Department of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, Rome, Italy
| | - R Purrello
- Department of Chemical Sciences, University of Catania, Catania, Italy
| | - G Graziani
- Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy.
| | - M Coletta
- Department of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, Rome, Italy.
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45
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Scull NW, Lucius AL. Kinetic Analysis of AAA+ Translocases by Combined Fluorescence and Anisotropy Methods. Biophys J 2020; 119:1335-1350. [PMID: 32997959 DOI: 10.1016/j.bpj.2020.08.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 08/03/2020] [Accepted: 08/17/2020] [Indexed: 11/30/2022] Open
Abstract
The multitude of varied, energy-dependent processes that exist in the cell necessitate a diverse array of macromolecular machines to maintain homeostasis, allow for growth, and facilitate reproduction. ATPases associated with various cellular activity are a set of protein assemblies that function as molecular motors to couple the energy of nucleoside triphosphate binding and hydrolysis to mechanical movement along a polymer lattice. A recent boom in structural insights into these motors has led to structural hypotheses on how these motors fulfill their function. However, in many cases, we lack direct kinetic measurements of the dynamic processes these motors undergo as they transition between observed structural states. Consequently, there is a need for improved techniques for testing the structural hypotheses in solution. Here, we apply transient-state fluorescence anisotropy and total fluorescence stopped-flow methods to the analysis of polypeptide translocation catalyzed by these ATPase motors. We specifically focus on the Hsp100-Clp protein system of ClpA, which is a well-studied, model ATPases associated with various cellular activity system that has both eukaryotic and archaea homologs. Using this system, we show that we can reproduce previously established kinetic parameters from the simultaneous analysis of fluorescence anisotropy and total fluorescence and overcome previous limitations of our previous approach. Specifically, for the first time, to our knowledge, we obtain quantitative interpretations of the translocation of polypeptide substrates longer than 100 aa.
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Affiliation(s)
- Nathaniel W Scull
- Department of Chemistry, University of Alabama at Birmingham, Birmingham, Alabama
| | - Aaron L Lucius
- Department of Chemistry, University of Alabama at Birmingham, Birmingham, Alabama.
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46
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Majumder P, Baumeister W. Proteasomes: unfoldase-assisted protein degradation machines. Biol Chem 2020; 401:183-199. [PMID: 31665105 DOI: 10.1515/hsz-2019-0344] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Accepted: 10/02/2019] [Indexed: 01/05/2023]
Abstract
Proteasomes are the principal molecular machines for the regulated degradation of intracellular proteins. These self-compartmentalized macromolecular assemblies selectively degrade misfolded, mistranslated, damaged or otherwise unwanted proteins, and play a pivotal role in the maintenance of cellular proteostasis, in stress response, and numerous other processes of vital importance. Whereas the molecular architecture of the proteasome core particle (CP) is universally conserved, the unfoldase modules vary in overall structure, subunit complexity, and regulatory principles. Proteasomal unfoldases are AAA+ ATPases (ATPases associated with a variety of cellular activities) that unfold protein substrates, and translocate them into the CP for degradation. In this review, we summarize the current state of knowledge about proteasome - unfoldase systems in bacteria, archaea, and eukaryotes, the three domains of life.
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Affiliation(s)
- Parijat Majumder
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany
| | - Wolfgang Baumeister
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany
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47
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Shin JY, Muniyappan S, Tran NN, Park H, Lee SB, Lee BH. Deubiquitination Reactions on the Proteasome for Proteasome Versatility. Int J Mol Sci 2020; 21:E5312. [PMID: 32726943 PMCID: PMC7432943 DOI: 10.3390/ijms21155312] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 07/21/2020] [Accepted: 07/23/2020] [Indexed: 12/17/2022] Open
Abstract
The 26S proteasome, a master player in proteolysis, is the most complex and meticulously contextured protease in eukaryotic cells. While capable of hosting thousands of discrete substrates due to the selective recognition of ubiquitin tags, this protease complex is also dynamically checked through diverse regulatory mechanisms. The proteasome's versatility ensures precise control over active proteolysis, yet prevents runaway or futile degradation of many essential cellular proteins. Among the multi-layered processes regulating the proteasome's proteolysis, deubiquitination reactions are prominent because they not only recycle ubiquitins, but also impose a critical checkpoint for substrate degradation on the proteasome. Of note, three distinct classes of deubiquitinating enzymes-USP14, RPN11, and UCH37-are associated with the 19S subunits of the human proteasome. Recent biochemical and structural studies suggest that these enzymes exert dynamic influence over proteasome output with limited redundancy, and at times act in opposition. Such distinct activities occur spatially on the proteasome, temporally through substrate processing, and differentially for ubiquitin topology. Therefore, deubiquitinating enzymes on the proteasome may fine-tune the degradation depending on various cellular contexts and for dynamic proteolysis outcomes. Given that the proteasome is among the most important drug targets, the biology of proteasome-associated deubiquitination should be further elucidated for its potential targeting in human diseases.
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Affiliation(s)
- Ji Yeong Shin
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea; (J.Y.S.); (S.M.); (N.-N.T.); (H.P.)
- Protein Dynamics-based Proteotoxicity Control Lab, Basic Research Lab, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea;
- Center for Cell Fate Reprogramming & Control, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
| | - Srinivasan Muniyappan
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea; (J.Y.S.); (S.M.); (N.-N.T.); (H.P.)
| | - Non-Nuoc Tran
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea; (J.Y.S.); (S.M.); (N.-N.T.); (H.P.)
- Protein Dynamics-based Proteotoxicity Control Lab, Basic Research Lab, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea;
- Center for Cell Fate Reprogramming & Control, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
| | - Hyeonjeong Park
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea; (J.Y.S.); (S.M.); (N.-N.T.); (H.P.)
- Protein Dynamics-based Proteotoxicity Control Lab, Basic Research Lab, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea;
| | - Sung Bae Lee
- Protein Dynamics-based Proteotoxicity Control Lab, Basic Research Lab, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea;
- Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
| | - Byung-Hoon Lee
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea; (J.Y.S.); (S.M.); (N.-N.T.); (H.P.)
- Protein Dynamics-based Proteotoxicity Control Lab, Basic Research Lab, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea;
- Center for Cell Fate Reprogramming & Control, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
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48
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Aichem A, Groettrup M. The ubiquitin-like modifier FAT10 - much more than a proteasome-targeting signal. J Cell Sci 2020; 133:133/14/jcs246041. [PMID: 32719056 DOI: 10.1242/jcs.246041] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Human leukocyte antigen (HLA)-F adjacent transcript 10 (FAT10) also called ubiquitin D (UBD) is a member of the ubiquitin-like modifier (ULM) family. The FAT10 gene is localized in the MHC class I locus and FAT10 protein expression is mainly restricted to cells and organs of the immune system. In all other cell types and tissues, FAT10 expression is highly inducible by the pro-inflammatory cytokines interferon (IFN)-γ and tumor necrosis factor (TNF). Besides ubiquitin, FAT10 is the only ULM which directly targets its substrates for degradation by the 26S proteasome. This poses the question as to why two ULMs sharing the proteasome-targeting function have evolved and how they differ from each other. This Review summarizes the current knowledge of the special structure of FAT10 and highlights its differences from ubiquitin. We discuss how these differences might result in differential outcomes concerning proteasomal degradation mechanisms and non-covalent target interactions. Moreover, recent insights about the structural and functional impact of FAT10 interacting with specific non-covalent interaction partners are reviewed.
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Affiliation(s)
- Annette Aichem
- Biotechnology Institute Thurgau at the University of Konstanz, CH-8280 Kreuzlingen, Switzerland.,Division of Immunology, Department of Biology, University of Konstanz, D-78457 Konstanz, Germany
| | - Marcus Groettrup
- Biotechnology Institute Thurgau at the University of Konstanz, CH-8280 Kreuzlingen, Switzerland .,Division of Immunology, Department of Biology, University of Konstanz, D-78457 Konstanz, Germany
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49
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Saha A, Oanca G, Mondal D, Warshel A. Exploring the Proteolysis Mechanism of the Proteasomes. J Phys Chem B 2020; 124:5626-5635. [PMID: 32498514 DOI: 10.1021/acs.jpcb.0c04435] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The proteasome is a key protease in the eukaryotic cells which is responsible for various important cellular processes such as the control of the cell cycle, immune responses, protein homeostasis, inflammation, apoptosis, and the response to proteotoxic stress. Acting as a major molecular machine for protein degradation, proteasome first identifies damaged or obsolete regulatory proteins by attaching ubiquitin chains and subsequently utilizes conserved pore loops of the heterohexameric ring of AAA+ (ATPases associated with diverse cellular activities) to pull and mechanically unfold and translocate the misfolded protein to the active site for proteolysis. A detailed knowledge of the reaction mechanism for this proteasomal proteolysis is of central importance, both for fundamental understanding and for drug discovery. The present study investigates the mechanism of the proteolysis by the proteasome with full consideration of the protein's flexibility and its impact on the reaction free energy. Major attention is paid to the role of the protein electrostatics in determining the activation barriers. The reaction mechanism is studied by considering a small artificial fluorogenic peptide substrate (Suc-LLVY-AMC) and evaluating the activation barriers and reaction free energies for the acylation and deacylation steps, by using the empirical valence bond method. Our results shed light on the proteolysis mechanism and thus should be important for further studies of the proteasome action.
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Affiliation(s)
- Arjun Saha
- Department of Chemistry, University of Southern California, 418 SGM Building, 3620 McClintock Ave., Los Angeles, California 90089-1062, United States
| | - Gabriel Oanca
- Department of Chemistry, University of Southern California, 418 SGM Building, 3620 McClintock Ave., Los Angeles, California 90089-1062, United States
| | - Dibyendu Mondal
- Department of Chemistry, University of Southern California, 418 SGM Building, 3620 McClintock Ave., Los Angeles, California 90089-1062, United States
| | - Arieh Warshel
- Department of Chemistry, University of Southern California, 418 SGM Building, 3620 McClintock Ave., Los Angeles, California 90089-1062, United States
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50
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Site-specific ubiquitination affects protein energetics and proteasomal degradation. Nat Chem Biol 2020; 16:866-875. [PMID: 32483380 DOI: 10.1038/s41589-020-0556-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 04/05/2020] [Accepted: 04/26/2020] [Indexed: 11/09/2022]
Abstract
Changes in the cellular environment modulate protein energy landscapes to drive important biology, with consequences for signaling, allostery and other vital processes. The effects of ubiquitination are particularly important because of their potential influence on degradation by the 26S proteasome. Moreover, proteasomal engagement requires unstructured initiation regions that many known proteasome substrates lack. To assess the energetic effects of ubiquitination and how these manifest at the proteasome, we developed a generalizable strategy to produce isopeptide-linked ubiquitin within structured regions of a protein. The effects on the energy landscape vary from negligible to dramatic, depending on the protein and site of ubiquitination. Ubiquitination at sensitive sites destabilizes the native structure and increases the rate of proteasomal degradation. In well-folded proteins, ubiquitination can even induce the requisite unstructured regions needed for proteasomal engagement. Our results indicate a biophysical role of site-specific ubiquitination as a potential regulatory mechanism for energy-dependent substrate degradation.
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