1
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Carver A, Zhang B, Zhang X. Structures and mechanisms of AAA+ protein complexes in DNA processing. Curr Opin Struct Biol 2025; 92:103056. [PMID: 40334521 DOI: 10.1016/j.sbi.2025.103056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2025] [Revised: 04/09/2025] [Accepted: 04/10/2025] [Indexed: 05/09/2025]
Abstract
AAA+ proteins are a large family of ATPases involved in a myriad of cellular activities. Recent advances in AAA+ proteins, especially cryoEM structures of these proteins in complex with their substrates, have provided key insights into how they function. Here we review recent progress in structural studies and mechanistic understanding of AAA+ proteins involved in DNA processing, including gene transcription, DNA replication, repair/recombination and transposition. Using a few selected examples, we show how AAA+ proteins act on both DNA and protein peptides, which are often enclosed in the pores of AAA+ hexamers. We propose that using AAA+ proteins to translocate a peptide to partially unfold a substrate is an effective strategy in disassembling an assembled complex. Further, several studies show that although they often act as asymmetric hexamers in their active form, AAA+ proteins adopt a range of oligomers for their functions.
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Affiliation(s)
- Alexander Carver
- Section of Structural and Synthetic Biology, Faculty of Medicine, Imperial College London, South Kensington, London, SW7 2AZ, UK; Laboratory of DNA Processing Machines, The Francis Crick Institute, London, NW1 1AT, UK
| | - Bowen Zhang
- Section of Structural and Synthetic Biology, Faculty of Medicine, Imperial College London, South Kensington, London, SW7 2AZ, UK; Laboratory of DNA Processing Machines, The Francis Crick Institute, London, NW1 1AT, UK
| | - Xiaodong Zhang
- Section of Structural and Synthetic Biology, Faculty of Medicine, Imperial College London, South Kensington, London, SW7 2AZ, UK; Laboratory of DNA Processing Machines, The Francis Crick Institute, London, NW1 1AT, UK.
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2
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Dai Y, Wu D, Li N, Ma C, Zhang Y, Gao N. Cryo-EM structure of the AAA+ SPATA5 complex and its role in human cytoplasmic pre-60S maturation. Nat Commun 2025; 16:3806. [PMID: 40268917 PMCID: PMC12019325 DOI: 10.1038/s41467-025-58894-0] [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: 08/07/2024] [Accepted: 04/03/2025] [Indexed: 04/25/2025] Open
Abstract
Eukaryotic ribosome biogenesis is an energy-consuming process involving many ATPase-driven steps. In yeast, AAA+ protein Drg1 releases an assembly factor Rlp24, a placeholder for Rpl24, from pre-60S particles just exported to cytosol. The equivalent process in human cells involves SPATA5 (Drg1 homolog) and additional factors. However, the mechanistic details remain unclear. Here we reveal that SPATA5 forms a 4:2:2:2 complex with SPATA5L1, C1orf109, and CINP. This complex features an N-terminal ring made of C1orf109, CINP and NTDs of SPATA5/SPATA5L1, and two hexameric AAA+ ATPase rings. Intriguingly, a conserved cysteine C672 in the P-loop of SPATA5 is sulfinylated, generating an inactive conformation incompatible with ATP binding. We also obtained a cryo-EM structure of pre-60S-bound SPATA5 complex. Different from yeast, the recognition of the pre-60S particle is mediated by human-specific factor CINP, through two distinct sets of interactions: one with GTPBP4 and the other with ES27A. Taken together, these data provide structural basis for understanding the cytoplasmic maturation of the pre-60S, and reveal human-specific features that might be harnessed for therapeutic purposes.
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Affiliation(s)
- Yuhao Dai
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing, China
- Peking University-Tsinghua University-National Institute of Biological Sciences Joint Graduate Program, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Damu Wu
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing, China
- Peking University-Tsinghua University-National Institute of Biological Sciences Joint Graduate Program, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Ningning Li
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing, China
| | - Chengying Ma
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing, China
| | - Yunyang Zhang
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing, China.
| | - Ning Gao
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing, China.
- National Biomedical Imaging Center, Peking University, Beijing, China.
- Beijing Advanced Center of RNA Biology (BEACON), Peking University, Beijing, China.
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3
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Kahawatte S, Macke AC, St Clair C, Dima RI. A Major Disease-Related Point Mutation in Spastin Dramatically Alters the Dynamics and Allostery of the Motor. Biochemistry 2025; 64:1293-1307. [PMID: 40009545 DOI: 10.1021/acs.biochem.4c00693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2025]
Abstract
Spastin is a microtubule-severing AAA+ ATPase that is highly expressed in neuronal cells and plays a crucial role in axonal growth, branching, and regeneration. This machine oligomerizes into hexamers in the presence of ATP and microtubule carboxy-terminal tails (CTTs). Conformational changes in spastin hexamers, powered by ATP hydrolysis, apply forces to the microtubule, ultimately leading to the severing of the filament. Mutations disrupt the normal function of spastin, impairing its ability to sever microtubules effectively and leading to abnormal microtubule dynamics in neurons characteristic of the set of neurodegenerative disorders called hereditary spastic paraplegias (HSP). Experimental studies have identified the HSP-related R591S (Drosophila melanogaster numbering) mutation as playing a crucial role in spastin. Given its significant role in HSP, we employed a combination of molecular dynamics simulations with machine learning and graph network-based approaches to identify and quantify the perturbations caused by the R591S HSP mutation on spastin's dynamics and allostery with functional implications. We found that the functional hexamer, upon HSP-related mutation, loses the ability to execute the primary motion associated with the severing action. The study of allosteric changes upon the mutation showed that the regions that are most perturbed are those involved in the formation of the interprotomer contacts. The mutation induces rigidity in the allosteric networks of the motor, making it more likely to experience loss of function as applied perturbations would not be easily dissipated by passing through a variety of alternative paths as in the wild-type (WT) spastin.
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Affiliation(s)
- Shehani Kahawatte
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Amanda C Macke
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Carter St Clair
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
- Department of Chemistry, University of St. Francis, Joliet, Illinois 60435, United States
| | - Ruxandra I Dima
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
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4
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Jang J, Kang Y, Zofall M, Woo S, An S, Cho C, Grewal S, Lee JY, Song JJ. Abo1 ATPase facilitates the dissociation of FACT from chromatin. Nucleic Acids Res 2025; 53:gkae1229. [PMID: 39676666 PMCID: PMC11879132 DOI: 10.1093/nar/gkae1229] [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: 06/19/2024] [Revised: 10/29/2024] [Accepted: 11/27/2024] [Indexed: 12/17/2024] Open
Abstract
The histone chaperone FAcilitates Chromatin Transcription (FACT) is a heterodimeric complex consisting of Spt16 and Pob3, crucial for preserving nucleosome integrity during transcription and DNA replication. Loss of FACT leads to cryptic transcription and heterochromatin defects. FACT was shown to interact with Abo1, an AAA + family histone chaperone involved in nucleosome dynamics. Depletion of Abo1 causes FACT to stall at transcription start sites and mimics FACT mutants, indicating a functional association between Abo1 and FACT. However, the precise role of Abo1 in FACT function remains poorly understood. Here, we reveal that Abo1 directly interacts with FACT and facilitates the dissociation of FACT from nucleosome. Specifically, the N-terminal region of Abo1 utilizes its FACT-interacting helix to bind to the N-terminal domain of Spt16. In addition, using single-molecule fluorescence imaging, we discovered that Abo1 facilitates the ATP-dependent dissociation of FACT from nucleosomes. Furthermore, we demonstrate that the interaction between Abo1 and FACT is essential for maintaining heterochromatin in fission yeast. In summary, our findings suggest that Abo1 regulates FACT turnover in an ATP-dependent manner, proposing a model of histone chaperone recycling driven by inter-chaperone interactions.
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Affiliation(s)
- Juwon Jang
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), KI for the BioCentury, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Korea
| | - Yujin Kang
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, 50, UNIST-gil, Eonyang-eup, Ulju-gun, Ulsan, 44919, Korea
| | - Martin Zofall
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, 9000 Rockville Pike, Bethesda, MD 20892, USA
| | - Sangmin Woo
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), KI for the BioCentury, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Korea
| | - Soyeong An
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, 50, UNIST-gil, Eonyang-eup, Ulju-gun, Ulsan, 44919, Korea
| | - Carol Cho
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), KI for the BioCentury, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Korea
| | - Shiv Grewal
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, 9000 Rockville Pike, Bethesda, MD 20892, USA
| | - Ja Yil Lee
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, 50, UNIST-gil, Eonyang-eup, Ulju-gun, Ulsan, 44919, Korea
| | - Ji-Joon Song
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), KI for the BioCentury, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Korea
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Feng Y, Goncalves MM, Jitkova Y, Keszei AFA, Yan Y, Sarathy C, St-Germain J, Kenney TMG, Tcheng M, Trudel V, Mancini RS, Upadhyay R, Hurren R, Gronda M, Schultz M, Soriano K, Lees K, Pomroy NC, Currie SQW, Privé GG, Reed MA, Yudin AK, Penn LZ, Arrowsmith CH, Raught B, Mazhab-Jafari MT, Vahidi S, Schimmer AD. Serine phosphorylation facilitates protein degradation by the human mitochondrial ClpXP protease. Proc Natl Acad Sci U S A 2025; 122:e2422447122. [PMID: 39879245 PMCID: PMC11804671 DOI: 10.1073/pnas.2422447122] [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: 10/31/2024] [Accepted: 12/20/2024] [Indexed: 01/31/2025] Open
Abstract
ClpXP is a two-component mitochondrial matrix protease. The caseinolytic mitochondrial matrix peptidase chaperone subunit X (ClpX) recognizes and translocates protein substrates into the degradation chamber of the caseinolytic protease P (ClpP) for proteolysis. ClpXP degrades damaged respiratory chain proteins and is necessary for cancer cell survival. Despite the critical role of ClpXP in mitochondrial protein quality control, the specific degrons, or modifications that tag substrate proteins for degradation by human ClpXP, are still unknown. We demonstrated that phosphorylated serine (pSer) targets substrates to ClpX and facilitates their degradation by ClpXP in biochemical assays. In contrast, ClpP hyperactivated by the small-molecule drug ONC201 lost the preference for phosphorylated substrates. Hydrogen deuterium exchange mass spectrometry combined with biochemical assays showed that pSer binds the RKL loop of ClpX. ClpX variants with substitutions in the RKL loop failed to recognize phosphorylated substrates. In intact cells, ClpXP also preferentially degraded substrates with pSer. Moreover, ClpX substrates with the pSer were selectively found in aggregated mitochondrial proteins. Our work uncovers a mechanism for substrate recognition by ClpXP, with implications for targeting acute myeloid leukemia and other disorders involving ClpXP dysfunction.
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Affiliation(s)
- Yue Feng
- Princess Margaret Cancer Centre, University Health Network, Toronto, ONM5G 1L7, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ONM5G 1L7, Canada
| | - Monica M. Goncalves
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ONN1G 2W1, Canada
| | - Yulia Jitkova
- Princess Margaret Cancer Centre, University Health Network, Toronto, ONM5G 1L7, Canada
| | | | - Yongran Yan
- Princess Margaret Cancer Centre, University Health Network, Toronto, ONM5G 1L7, Canada
| | - Chaitra Sarathy
- Princess Margaret Cancer Centre, University Health Network, Toronto, ONM5G 1L7, Canada
| | - Jonathan St-Germain
- Princess Margaret Cancer Centre, University Health Network, Toronto, ONM5G 1L7, Canada
| | - Tristan M. G. Kenney
- Princess Margaret Cancer Centre, University Health Network, Toronto, ONM5G 1L7, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ONM5G 1L7, Canada
| | - Matthew Tcheng
- Princess Margaret Cancer Centre, University Health Network, Toronto, ONM5G 1L7, Canada
| | - Vincent Trudel
- Department of Chemistry, University of Toronto, Toronto, ONM5S 3H6, Canada
| | - Ross S. Mancini
- Krembil Brain Institute, University Health Network, Toronto, ONM5T 1M8, Canada
| | - Rahul Upadhyay
- Krembil Brain Institute, University Health Network, Toronto, ONM5T 1M8, Canada
| | - Rose Hurren
- Princess Margaret Cancer Centre, University Health Network, Toronto, ONM5G 1L7, Canada
| | - Marcela Gronda
- Princess Margaret Cancer Centre, University Health Network, Toronto, ONM5G 1L7, Canada
| | - Matthew Schultz
- Princess Margaret Cancer Centre, University Health Network, Toronto, ONM5G 1L7, Canada
| | - Kaylen Soriano
- Princess Margaret Cancer Centre, University Health Network, Toronto, ONM5G 1L7, Canada
| | - Kaitlin Lees
- Princess Margaret Cancer Centre, University Health Network, Toronto, ONM5G 1L7, Canada
| | - Neil C. Pomroy
- Princess Margaret Cancer Centre, University Health Network, Toronto, ONM5G 1L7, Canada
| | - S. Quinn W. Currie
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ONN1G 2W1, Canada
| | - Gilbert G. Privé
- Princess Margaret Cancer Centre, University Health Network, Toronto, ONM5G 1L7, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ONM5G 1L7, Canada
| | - Mark A. Reed
- Department of Chemistry, University of Toronto, Toronto, ONM5S 3H6, Canada
- Krembil Brain Institute, University Health Network, Toronto, ONM5T 1M8, Canada
- Department of Pharmacology & Toxicology, University of Toronto, Toronto, ONM5S 1A8, Canada
| | - Andrei K. Yudin
- Department of Chemistry, University of Toronto, Toronto, ONM5S 3H6, Canada
| | - Linda Z. Penn
- Princess Margaret Cancer Centre, University Health Network, Toronto, ONM5G 1L7, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ONM5G 1L7, Canada
| | - Cheryl H. Arrowsmith
- Princess Margaret Cancer Centre, University Health Network, Toronto, ONM5G 1L7, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ONM5G 1L7, Canada
- Structural Genomics Consortium, University of Toronto, Toronto, ONM5G 1L7, Canada
| | - Brian Raught
- Princess Margaret Cancer Centre, University Health Network, Toronto, ONM5G 1L7, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ONM5G 1L7, Canada
| | - Mohammad T. Mazhab-Jafari
- Princess Margaret Cancer Centre, University Health Network, Toronto, ONM5G 1L7, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ONM5G 1L7, Canada
| | - Siavash Vahidi
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ONN1G 2W1, Canada
| | - Aaron D. Schimmer
- Princess Margaret Cancer Centre, University Health Network, Toronto, ONM5G 1L7, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ONM5G 1L7, Canada
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6
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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 2025; 26:104-122. [PMID: 39362999 PMCID: PMC11772106 DOI: 10.1038/s41580-024-00778-0] [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] [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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Liao F, Yu G, Zhang C, Liu Z, Li X, He Q, Yin H, Liu X, Li Z, Zhang H. Structural basis for the concerted antiphage activity in the SIR2-HerA system. Nucleic Acids Res 2024; 52:11336-11348. [PMID: 39217465 PMCID: PMC11472057 DOI: 10.1093/nar/gkae750] [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: 11/26/2023] [Revised: 08/07/2024] [Accepted: 08/19/2024] [Indexed: 09/04/2024] Open
Abstract
Recently, a novel two-gene bacterial defense system against phages, encoding a SIR2 NADase and a HerA ATPase/helicase, has been identified. However, the molecular mechanism of the bacterial SIR2-HerA immune system remains unclear. Here, we determine the cryo-EM structures of SIR2, HerA and their complex from Paenibacillus sp. 453MF in different functional states. The SIR2 proteins oligomerize into a dodecameric ring-shaped structure consisting of two layers of interlocked hexamers, in which each subunit exhibits an auto-inhibited conformation. Distinct from the canonical AAA+ proteins, HerA hexamer alone in this antiphage system adopts a split spiral arrangement, which is stabilized by a unique C-terminal extension. SIR2 and HerA proteins assemble into a ∼1.1 MDa torch-shaped complex to fight against phage infection. Importantly, disruption of the interactions between SIR2 and HerA largely abolishes the antiphage activity. Interestingly, binding alters the oligomer state of SIR2, switching from a dodecamer to a tetradecamer state. The formation of the SIR2-HerA binary complex activates NADase and nuclease activities in SIR2 and ATPase and helicase activities in HerA. Together, our study not only provides a structural basis for the functional communications between SIR2 and HerA proteins, but also unravels a novel concerted antiviral mechanism through NAD+ degradation, ATP hydrolysis, and DNA cleavage.
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Affiliation(s)
- Fumeng Liao
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, International Joint Laboratory of Ocular Diseases (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Tianjin Key Laboratory of Cellular Homeostasis and Disease, School of Basic Medical Sciences, Tianjin Medical University, Tianjin 300070, China
| | - Guimei Yu
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, International Joint Laboratory of Ocular Diseases (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Tianjin Key Laboratory of Cellular Homeostasis and Disease, School of Basic Medical Sciences, Tianjin Medical University, Tianjin 300070, China
| | - Chendi Zhang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Zhikun Liu
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, International Joint Laboratory of Ocular Diseases (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Tianjin Key Laboratory of Cellular Homeostasis and Disease, School of Basic Medical Sciences, Tianjin Medical University, Tianjin 300070, China
| | - Xuzichao Li
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, International Joint Laboratory of Ocular Diseases (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Tianjin Key Laboratory of Cellular Homeostasis and Disease, School of Basic Medical Sciences, Tianjin Medical University, Tianjin 300070, China
| | - Qiuqiu He
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, International Joint Laboratory of Ocular Diseases (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Tianjin Key Laboratory of Cellular Homeostasis and Disease, School of Basic Medical Sciences, Tianjin Medical University, Tianjin 300070, China
| | - Hang Yin
- Department of Pharmacology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin 300070, China
| | - Xiang Liu
- State Key Laboratory of Medicinal Chemical Biology, Frontiers Science Center for Cell Responses, College of Life Sciences, Nankai University, Tianjin, China
| | - Zhuang Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Heng Zhang
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, International Joint Laboratory of Ocular Diseases (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Tianjin Key Laboratory of Cellular Homeostasis and Disease, School of Basic Medical Sciences, Tianjin Medical University, Tianjin 300070, China
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8
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Banwait JK, Islam L, Lucius AL. Single turnover transient state kinetics reveals processive protein unfolding catalyzed by Escherichia coli ClpB. eLife 2024; 13:RP99052. [PMID: 39374121 PMCID: PMC11458177 DOI: 10.7554/elife.99052] [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] [Indexed: 10/09/2024] Open
Abstract
Escherichia coli ClpB and Saccharomyces cerevisiae Hsp104 are AAA+ motor proteins essential for proteome maintenance and thermal tolerance. ClpB and Hsp104 have been proposed to extract a polypeptide from an aggregate and processively translocate the chain through the axial channel of its hexameric ring structure. However, the mechanism of translocation and if this reaction is processive remains disputed. We reported that Hsp104 and ClpB are non-processive on unfolded model substrates. Others have reported that ClpB is able to processively translocate a mechanically unfolded polypeptide chain at rates over 240 amino acids (aa) per second. Here, we report the development of a single turnover stopped-flow fluorescence strategy that reports on processive protein unfolding catalyzed by ClpB. We show that when translocation catalyzed by ClpB is challenged by stably folded protein structure, the motor enzymatically unfolds the substrate at a rate of ~0.9 aa s-1 with a kinetic step-size of ~60 amino acids at sub-saturating [ATP]. We reconcile the apparent controversy by defining enzyme catalyzed protein unfolding and translocation as two distinct reactions with different mechanisms of action. We propose a model where slow unfolding followed by fast translocation represents an important mechanistic feature that allows the motor to rapidly translocate up to the next folded region or rapidly dissociate if no additional fold is encountered.
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Affiliation(s)
| | - Liana Islam
- Department of Chemistry, University of Alabama at BirminghamBirminghamUnited States
| | - Aaron L Lucius
- Department of Chemistry, University of Alabama at BirminghamBirminghamUnited States
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9
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Cooney I, Schubert HL, Cedeno K, Fisher ON, Carson R, Price JC, Hill CP, Shen PS. Visualization of the Cdc48 AAA+ ATPase protein unfolding pathway. Nat Commun 2024; 15:7505. [PMID: 39209885 PMCID: PMC11362554 DOI: 10.1038/s41467-024-51835-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Accepted: 08/20/2024] [Indexed: 09/04/2024] Open
Abstract
The Cdc48 AAA+ ATPase is an abundant and essential enzyme that unfolds substrates in multiple protein quality control pathways. The enzyme includes two conserved AAA+ ATPase motor domains, D1 and D2, that assemble as hexameric rings with D1 stacked above D2. Here, we report an ensemble of native structures of Cdc48 affinity purified from budding yeast lysate in complex with the adaptor Shp1 in the act of unfolding substrate. Our analysis reveals a continuum of structural snapshots that spans the entire translocation cycle. These data uncover elements of Shp1-Cdc48 interactions and support a 'hand-over-hand' mechanism in which the sequential movement of individual subunits is closely coordinated. D1 hydrolyzes ATP and disengages from substrate prior to D2, while D2 rebinds ATP and re-engages with substrate prior to D1, thereby explaining the dominant role played by the D2 motor in substrate translocation/unfolding.
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Affiliation(s)
- Ian Cooney
- Department of Biochemistry, University of Utah, Salt Lake City, UT, USA
| | - Heidi L Schubert
- Department of Biochemistry, University of Utah, Salt Lake City, UT, USA
| | - Karina Cedeno
- Department of Biochemistry, University of Utah, Salt Lake City, UT, USA
| | - Olivia N Fisher
- Department of Biochemistry, University of Utah, Salt Lake City, UT, USA
| | - Richard Carson
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, USA
| | - John C Price
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, USA
| | - Christopher P Hill
- Department of Biochemistry, University of Utah, Salt Lake City, UT, USA.
| | - Peter S Shen
- Department of Biochemistry, University of Utah, Salt Lake City, UT, USA.
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10
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Bohl V, Mogk A. When the going gets tough, the tough get going-Novel bacterial AAA+ disaggregases provide extreme heat resistance. Environ Microbiol 2024; 26:e16677. [PMID: 39039821 DOI: 10.1111/1462-2920.16677] [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: 04/29/2024] [Accepted: 07/05/2024] [Indexed: 07/24/2024]
Abstract
Heat stress can lead to protein misfolding and aggregation, potentially causing cell death due to the loss of essential proteins. Bacteria, being particularly exposed to environmental stress, are equipped with disaggregases that rescue these aggregated proteins. The bacterial Hsp70 chaperone DnaK and the ATPase associated with diverse cellular activities protein ClpB form the canonical disaggregase in bacteria. While this combination operates effectively during physiological heat stress, it is ineffective against massive aggregation caused by temperature-based sterilization protocols used in the food industry and clinics. This leaves bacteria unprotected against these thermal processes. However, bacteria that can withstand extreme, man-made stress conditions have emerged. These bacteria possess novel ATPase associated with diverse cellular activities disaggregases, ClpG and ClpL, which are key players in extreme heat resistance. These disaggregases, present in selected Gram-negative or Gram-positive bacteria, respectively, function superiorly by exhibiting increased thermal stability and enhanced threading power compared to DnaK/ClpB. This enables ClpG and ClpL to operate at extreme temperatures and process large and tight protein aggregates, thereby contributing to heat resistance. The genes for ClpG and ClpL are often encoded on mobile genomic islands or conjugative plasmids, allowing for their rapid spread among bacteria via horizontal gene transfer. This threatens the efficiency of sterilization protocols. In this review, we describe the various bacterial disaggregases identified to date, characterizing their commonalities and the specific features that enable these novel disaggregases to provide stress protection against extreme stress conditions.
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Affiliation(s)
- Valentin Bohl
- Faculty of Biosciences, Center for Molecular Biology of Heidelberg University (ZMBH), Heidelberg, Germany
| | - Axel Mogk
- Faculty of Biosciences, Center for Molecular Biology of Heidelberg University (ZMBH), Heidelberg, Germany
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11
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Mindrebo JT, Lander GC. Structural and mechanistic studies on human LONP1 redefine the hand-over-hand translocation mechanism. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.24.600538. [PMID: 38979310 PMCID: PMC11230189 DOI: 10.1101/2024.06.24.600538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
AAA+ enzymes use energy from ATP hydrolysis to remodel diverse cellular targets. Structures of substrate-bound AAA+ complexes suggest that these enzymes employ a conserved hand-over-hand mechanism to thread substrates through their central pore. However, the fundamental aspects of the mechanisms governing motor function and substrate processing within specific AAA+ families remain unresolved. We used cryo-electron microscopy to structurally interrogate reaction intermediates from in vitro biochemical assays to inform the underlying regulatory mechanisms of the human mitochondrial AAA+ protease, LONP1. Our results demonstrate that substrate binding allosterically regulates proteolytic activity, and that LONP1 can adopt a configuration conducive to substrate translocation even when the ATPases are bound to ADP. These results challenge the conventional understanding of the hand-over-hand translocation mechanism, giving rise to an alternative model that aligns more closely with biochemical and biophysical data on related enzymes like ClpX, ClpA, the 26S proteasome, and Lon protease.
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Affiliation(s)
- Jeffrey T. Mindrebo
- Department of Integrative Structural and Computational Biology, Scripps Research; La Jolla, CA, USA
| | - Gabriel C. Lander
- Department of Integrative Structural and Computational Biology, Scripps Research; La Jolla, CA, USA
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12
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Zhan J, Zeher A, Huang R, Tang WK, Jenkins LM, Xia D. Conformations of Bcs1L undergoing ATP hydrolysis suggest a concerted translocation mechanism for folded iron-sulfur protein substrate. Nat Commun 2024; 15:4655. [PMID: 38821922 PMCID: PMC11143374 DOI: 10.1038/s41467-024-49029-y] [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: 10/10/2023] [Accepted: 05/20/2024] [Indexed: 06/02/2024] Open
Abstract
The human AAA-ATPase Bcs1L translocates the fully assembled Rieske iron-sulfur protein (ISP) precursor across the mitochondrial inner membrane, enabling respiratory Complex III assembly. Exactly how the folded substrate is bound to and released from Bcs1L has been unclear, and there has been ongoing debate as to whether subunits of Bcs1L act in sequence or in unison hydrolyzing ATP when moving the protein cargo. Here, we captured Bcs1L conformations by cryo-EM during active ATP hydrolysis in the presence or absence of ISP substrate. In contrast to the threading mechanism widely employed by AAA proteins in substrate translocation, subunits of Bcs1L alternate uniformly between ATP and ADP conformations without detectable intermediates that have different, co-existing nucleotide states, indicating that the subunits act in concert. We further show that the ISP can be trapped by Bcs1 when its subunits are all in the ADP-bound state, which we propose to be released in the apo form.
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Affiliation(s)
- Jingyu Zhan
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Allison Zeher
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
- NIH Intramural Cryo-EM Consortium (NICE), Bethesda, MD, USA
| | - Rick Huang
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
- NIH Intramural Cryo-EM Consortium (NICE), Bethesda, MD, USA
| | - Wai Kwan Tang
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Lisa M Jenkins
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Di Xia
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA.
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13
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Skowyra ML, Feng P, Rapoport TA. Towards solving the mystery of peroxisomal matrix protein import. Trends Cell Biol 2024; 34:388-405. [PMID: 37743160 PMCID: PMC10957506 DOI: 10.1016/j.tcb.2023.08.005] [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: 06/12/2023] [Revised: 08/21/2023] [Accepted: 08/25/2023] [Indexed: 09/26/2023]
Abstract
Peroxisomes are vital metabolic organelles that import their lumenal (matrix) enzymes from the cytosol using mobile receptors. Surprisingly, the receptors can even import folded proteins, but the underlying mechanism has been a mystery. Recent results reveal how import receptors shuttle cargo into peroxisomes. The cargo-bound receptors move from the cytosol across the peroxisomal membrane completely into the matrix by a mechanism that resembles transport through the nuclear pore. The receptors then return to the cytosol through a separate retrotranslocation channel, leaving the cargo inside the organelle. This cycle concentrates imported proteins within peroxisomes, and the energy for cargo import is supplied by receptor export. Peroxisomal protein import thus fundamentally differs from other previously known mechanisms for translocating proteins across membranes.
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Affiliation(s)
- Michael L Skowyra
- Howard Hughes Medical Institute and Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
| | - Peiqiang Feng
- Howard Hughes Medical Institute and Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
| | - Tom A Rapoport
- Howard Hughes Medical Institute and Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA.
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14
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Krishnamoorthy V, Foglizzo M, Dilley RL, Wu A, Datta A, Dutta P, Campbell LJ, Degtjarik O, Musgrove LJ, Calabrese AN, Zeqiraj E, Greenberg RA. The SPATA5-SPATA5L1 ATPase complex directs replisome proteostasis to ensure genome integrity. Cell 2024; 187:2250-2268.e31. [PMID: 38554706 PMCID: PMC11055677 DOI: 10.1016/j.cell.2024.03.002] [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: 02/02/2023] [Revised: 12/27/2023] [Accepted: 03/02/2024] [Indexed: 04/02/2024]
Abstract
Ubiquitin-dependent unfolding of the CMG helicase by VCP/p97 is required to terminate DNA replication. Other replisome components are not processed in the same fashion, suggesting that additional mechanisms underlie replication protein turnover. Here, we identify replisome factor interactions with a protein complex composed of AAA+ ATPases SPATA5-SPATA5L1 together with heterodimeric partners C1orf109-CINP (55LCC). An integrative structural biology approach revealed a molecular architecture of SPATA5-SPATA5L1 N-terminal domains interacting with C1orf109-CINP to form a funnel-like structure above a cylindrically shaped ATPase motor. Deficiency in the 55LCC complex elicited ubiquitin-independent proteotoxicity, replication stress, and severe chromosome instability. 55LCC showed ATPase activity that was specifically enhanced by replication fork DNA and was coupled to cysteine protease-dependent cleavage of replisome substrates in response to replication fork damage. These findings define 55LCC-mediated proteostasis as critical for replication fork progression and genome stability and provide a rationale for pathogenic variants seen in associated human neurodevelopmental disorders.
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Affiliation(s)
- Vidhya Krishnamoorthy
- Department of Cancer Biology, Penn Center for Genome Integrity, Basser Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6160, USA
| | - Martina Foglizzo
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Robert L Dilley
- Department of Cancer Biology, Penn Center for Genome Integrity, Basser Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6160, USA.
| | - Angela Wu
- Department of Cancer Biology, Penn Center for Genome Integrity, Basser Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6160, USA
| | - Arindam Datta
- Department of Cancer Biology, Penn Center for Genome Integrity, Basser Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6160, USA
| | - Parul Dutta
- Department of Cancer Biology, Penn Center for Genome Integrity, Basser Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6160, USA
| | - Lisa J Campbell
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Oksana Degtjarik
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Laura J Musgrove
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Antonio N Calabrese
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Elton Zeqiraj
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.
| | - Roger A Greenberg
- Department of Cancer Biology, Penn Center for Genome Integrity, Basser Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6160, USA.
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15
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Marcus K, Huang Y, Subramanian S, Gee CL, Gorday K, Ghaffari-Kashani S, Luo XR, Zheng L, O'Donnell M, Subramaniam S, Kuriyan J. Autoinhibition of a clamp-loader ATPase revealed by deep mutagenesis and cryo-EM. Nat Struct Mol Biol 2024; 31:424-435. [PMID: 38177685 PMCID: PMC10950542 DOI: 10.1038/s41594-023-01177-3] [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: 07/10/2023] [Accepted: 11/08/2023] [Indexed: 01/06/2024]
Abstract
Clamp loaders are AAA+ ATPases that facilitate high-speed DNA replication. In eukaryotic and bacteriophage clamp loaders, ATP hydrolysis requires interactions between aspartate residues in one protomer, present in conserved 'DEAD-box' motifs, and arginine residues in adjacent protomers. We show that functional defects resulting from a DEAD-box mutation in the T4 bacteriophage clamp loader can be compensated by widely distributed single mutations in the ATPase domain. Using cryo-EM, we discovered an unsuspected inactive conformation of the clamp loader, in which DNA binding is blocked and the catalytic sites are disassembled. Mutations that restore function map to regions of conformational change upon activation, suggesting that these mutations may increase DNA affinity by altering the energetic balance between inactive and active states. Our results show that there are extensive opportunities for evolution to improve catalytic efficiency when an inactive intermediate is involved.
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Affiliation(s)
- Kendra Marcus
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Yongjian Huang
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Subu Subramanian
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Christine L Gee
- Howard Hughes Medical Institute, University of California, Berkeley, CA, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Kent Gorday
- Biophysics Graduate Group, University of California, Berkeley, CA, USA
| | - Sam Ghaffari-Kashani
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Xiao Ran Luo
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Lisa Zheng
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Michael O'Donnell
- Howard Hughes Medical Institute, The Rockefeller University, New York, NY, USA
| | - Sriram Subramaniam
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
| | - John Kuriyan
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA.
- Department of Chemistry, Vanderbilt University, Nashville, TN, USA.
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16
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Iljina M, Mazal H, Dayananda A, Zhang Z, Stan G, Riven I, Haran G. Single-molecule FRET probes allosteric effects on protein-translocating pore loops of a AAA+ machine. Biophys J 2024; 123:374-388. [PMID: 38196191 PMCID: PMC10870172 DOI: 10.1016/j.bpj.2024.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 11/07/2023] [Accepted: 01/02/2024] [Indexed: 01/11/2024] Open
Abstract
AAA+ proteins (ATPases associated with various cellular activities) comprise a family of powerful ring-shaped ATP-dependent translocases that carry out numerous vital substrate-remodeling functions. ClpB is a AAA+ protein disaggregation machine that forms a two-tiered hexameric ring, with flexible pore loops protruding into its center and binding to substrate proteins. It remains unknown whether these pore loops contribute only passively to substrate-protein threading or have a more active role. Recently, we have applied single-molecule FRET spectroscopy to directly measure the dynamics of substrate-binding pore loops in ClpB. We have reported that the three pore loops of ClpB (PL1-3) undergo large-scale fluctuations on the microsecond timescale that are likely to be mechanistically important for disaggregation. Here, using single-molecule FRET, we study the allosteric coupling between the pore loops and the two nucleotide-binding domains of ClpB (NBD1-2). By mutating the conserved Walker B motifs within the NBDs to abolish ATP hydrolysis, we demonstrate how the nucleotide state of each NBD tunes pore-loop dynamics. This effect is surprisingly long-ranged; in particular, PL2 and PL3 respond differentially to a Walker B mutation in either NBD1 or NBD2, as well as to mutations in both. We characterize the conformational dynamics of pore loops and the allosteric paths connecting NBDs to pore loops by molecular dynamics simulations and find that both principal motions and allosteric paths can be altered by changing the ATPase state of ClpB. Remarkably, PL3, which is highly conserved in AAA+ machines, is found to favor an upward conformation when only NBD1 undergoes ATP hydrolysis but a downward conformation when NBD2 is active. These results explicitly demonstrate a significant long-range allosteric effect of ATP hydrolysis sites on pore-loop dynamics. Pore loops are therefore established as active participants that undergo ATP-dependent conformational changes to translocate substrate proteins through the central pores of AAA+ machines.
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Affiliation(s)
- Marija Iljina
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Hisham Mazal
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Ashan Dayananda
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio
| | - Zhaocheng Zhang
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio
| | - George Stan
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio.
| | - Inbal Riven
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Gilad Haran
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel.
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17
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Ali BA, Judy RM, Chowdhury S, Jacobsen NK, Castanzo DT, Carr KL, Richardson CD, Lander GC, Martin A, Gardner BM. The N1 domain of the peroxisomal AAA-ATPase Pex6 is required for Pex15 binding and proper assembly with Pex1. J Biol Chem 2024; 300:105504. [PMID: 38036174 PMCID: PMC10777020 DOI: 10.1016/j.jbc.2023.105504] [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: 09/08/2023] [Revised: 11/07/2023] [Accepted: 11/17/2023] [Indexed: 12/02/2023] Open
Abstract
The heterohexameric ATPases associated with diverse cellular activities (AAA)-ATPase Pex1/Pex6 is essential for the formation and maintenance of peroxisomes. Pex1/Pex6, similar to other AAA-ATPases, uses the energy from ATP hydrolysis to mechanically thread substrate proteins through its central pore, thereby unfolding them. In related AAA-ATPase motors, substrates are recruited through binding to the motor's N-terminal domains or N terminally bound cofactors. Here, we use structural and biochemical techniques to characterize the function of the N1 domain in Pex6 from budding yeast, Saccharomyces cerevisiae. We found that although Pex1/ΔN1-Pex6 is an active ATPase in vitro, it does not support Pex1/Pex6 function at the peroxisome in vivo. An X-ray crystal structure of the isolated Pex6 N1 domain shows that the Pex6 N1 domain shares the same fold as the N-terminal domains of PEX1, CDC48, and NSF, despite poor sequence conservation. Integrating this structure with a cryo-EM reconstruction of Pex1/Pex6, AlphaFold2 predictions, and biochemical assays shows that Pex6 N1 mediates binding to both the peroxisomal membrane tether Pex15 and an extended loop from the D2 ATPase domain of Pex1 that influences Pex1/Pex6 heterohexamer stability. Given the direct interactions with both Pex15 and the D2 ATPase domains, the Pex6 N1 domain is poised to coordinate binding of cofactors and substrates with Pex1/Pex6 ATPase activity.
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Affiliation(s)
- Bashir A Ali
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, California, USA
| | - Ryan M Judy
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, California, USA
| | - Saikat Chowdhury
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California, USA; Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, USA; CSIR-Centre for Cellular and Molecular Biology, Hyderabad, Telangana, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh, India
| | - Nicole K Jacobsen
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, California, USA
| | - Dominic T Castanzo
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, California, USA
| | - Kaili L Carr
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, California, USA
| | - Chris D Richardson
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, California, USA
| | - Gabriel C Lander
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California, USA
| | - Andreas Martin
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, California, USA; California Institute for Quantitative Biosciences, University of California at Berkeley, Berkeley, California, USA; Howard Hughes Medical Institute, University of California at Berkeley, Berkeley, California, USA
| | - Brooke M Gardner
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, California, USA.
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18
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Luthuli SD, Shonhai A. The multi-faceted roles of R2TP complex span across regulation of gene expression, translation, and protein functional assembly. Biophys Rev 2023; 15:1951-1965. [PMID: 38192347 PMCID: PMC10771493 DOI: 10.1007/s12551-023-01127-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 08/27/2023] [Indexed: 01/10/2024] Open
Abstract
Macromolecular complexes play essential roles in various cellular processes. The assembly of macromolecular assemblies within the cell must overcome barriers imposed by a crowded cellular environment which is characterized by an estimated concentration of biological macromolecules amounting to 100-450 g/L that take up approximately 5-40% of the cytoplasmic volume. The formation of the macromolecular assemblies is facilitated by molecular chaperones in cooperation with their co-chaperones. The R2TP protein complex has emerged as a co-chaperone of Hsp90 that plays an important role in macromolecular assembly. The R2TP complex is composed of a heterodimer of RPAP3:P1H1DI that is in turn complexed to members of the ATPase associated with diverse cellular activities (AAA +), RUVBL1 and RUVBL2 (R1 and R2) families. What makes the R2TP co-chaperone complex particularly important is that it is involved in a wide variety of cellular processes including gene expression, translation, co-translational complex assembly, and posttranslational protein complex formation. The functional versatility of the R2TP co-chaperone complex makes it central to cellular development; hence, it is implicated in various human diseases. In addition, their roles in the development of infectious disease agents has become of interest. In the current review, we discuss the roles of these proteins as co-chaperones regulating Hsp90 and its partnership with Hsp70. Furthermore, we highlight the structure-function features of the individual proteins within the R2TP complex and describe their roles in various cellular processes.
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Affiliation(s)
- Sifiso Duncan Luthuli
- Department of Biochemistry and Microbiology, University of Venda, Thohoyandou, South Africa
| | - Addmore Shonhai
- Department of Biochemistry and Microbiology, University of Venda, Thohoyandou, South Africa
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19
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Petkov R, Camp AH, Isaacson RL, Torpey JH. Targeting bacterial degradation machinery as an antibacterial strategy. Biochem J 2023; 480:1719-1731. [PMID: 37916895 PMCID: PMC10657178 DOI: 10.1042/bcj20230191] [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: 05/16/2023] [Revised: 09/01/2023] [Accepted: 09/05/2023] [Indexed: 11/03/2023]
Abstract
The exploitation of a cell's natural degradation machinery for therapeutic purposes is an exciting research area in its infancy with respect to bacteria. Here, we review current strategies targeting the ClpCP system, which is a proteolytic degradation complex essential in the biology of many bacterial species of scientific interest. Strategies include using natural product antibiotics or acyldepsipeptides to initiate the up- or down-regulation of ClpCP activity. We also examine exciting recent forays into BacPROTACs to trigger the degradation of specific proteins of interest through the hijacking of the ClpCP machinery. These strategies represent an important emerging avenue for combatting antimicrobial resistance.
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Affiliation(s)
- Radoslav Petkov
- Department of Chemistry, King's College London, Britannia House, 7 Trinity Street, London SE1 1DB, U.K
| | - Amy H. Camp
- Department of Biological Sciences, Mount Holyoke College, 50 College Street, South Hadley, Massachusetts 01075, U.S.A
| | - Rivka L. Isaacson
- Department of Chemistry, King's College London, Britannia House, 7 Trinity Street, London SE1 1DB, U.K
| | - James H. Torpey
- Department of Chemistry, King's College London, Britannia House, 7 Trinity Street, London SE1 1DB, U.K
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20
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Katikaridis P, Simon B, Jenne T, Moon S, Lee C, Hennig J, Mogk A. Structural basis of aggregate binding by the AAA+ disaggregase ClpG. J Biol Chem 2023; 299:105336. [PMID: 37827289 PMCID: PMC10641755 DOI: 10.1016/j.jbc.2023.105336] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Revised: 09/17/2023] [Accepted: 09/26/2023] [Indexed: 10/14/2023] Open
Abstract
Severe heat stress causes massive loss of essential proteins by aggregation, necessitating a cellular activity that rescues aggregated proteins. This activity is executed by ATP-dependent, ring-forming, hexameric AAA+ disaggregases. Little is known about the recognition principles of stress-induced protein aggregates. How can disaggregases specifically target aggregated proteins, while avoiding binding to soluble non-native proteins? Here, we determined by NMR spectroscopy the core structure of the aggregate-targeting N1 domain of the bacterial AAA+ disaggregase ClpG, which confers extreme heat resistance to bacteria. N1 harbors a Zn2+-coordination site that is crucial for structural integrity and disaggregase functionality. We found that conserved hydrophobic N1 residues located on a β-strand are crucial for aggregate targeting and disaggregation activity. Analysis of mixed hexamers consisting of full-length and N1-truncated subunits revealed that a minimal number of four N1 domains must be present in a AAA+ ring for high-disaggregation activity. We suggest that multiple N1 domains increase substrate affinity through avidity effects. These findings define the recognition principle of a protein aggregate by a disaggregase, involving simultaneous contacts with multiple hydrophobic substrate patches located in close vicinity on an aggregate surface. This binding mode ensures selectivity for aggregated proteins while sparing soluble, non-native protein structures from disaggregase activity.
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Affiliation(s)
- Panagiotis Katikaridis
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany; German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Bernd Simon
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL) Heidelberg, Heidelberg, Germany; Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, Connecticut, USA
| | - Timo Jenne
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany; German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Seongjoon Moon
- Department of Biological Sciences, Ajou University, Suwon, South Korea
| | - Changhan Lee
- Department of Biological Sciences, Ajou University, Suwon, South Korea
| | - Janosch Hennig
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL) Heidelberg, Heidelberg, Germany; Division of Biophysical Chemistry, University of Bayreuth, Bayreuth, Germany.
| | - Axel Mogk
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany; German Cancer Research Center (DKFZ), Heidelberg, Germany.
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21
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Stanton DA, Ellis EA, Cruse MR, Jedlinski R, Kraut DA. The importance of proteasome grip depends on substrate stability. Biochem Biophys Res Commun 2023; 677:162-167. [PMID: 37591185 DOI: 10.1016/j.bbrc.2023.08.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 08/11/2023] [Indexed: 08/19/2023]
Abstract
The 26S proteasome is responsible for the unfolding and degradation of intracellular proteins in eukaryotes. A hexameric ring of ATPases (Rpt1-Rpt6) grabs onto substrates and unfolds them by pulling them through a central pore and translocating them into the 20S degradation chamber. A set of pore loops containing a so-called aromatic paddle motif in each Rpt subunit is believed to be important for the proteasome's ability to unfold and translocate substrates. Based on structural and mechanistic experiments, paddles from adjacent Rpt subunits, which are arrayed in a spiral staircase conformation, grip and pull on the substrate in a hand-over-hand type mechanism, disengaging at the bottom of the staircase and re-engaging at the top. We tested the contribution of the aromatic paddles to unfolding substrates of differing stabilities by mutating the paddles singly or in combination. For an easy-to-unfold substrate (a circular permutant of green fluorescent protein; GFP), mutations had little effect on degradation rates. For a substrate with moderate stability (enhanced GFP), there were modest effects of individual mutations on GFP unfolding rates, and alternating aromatic paddle mutants had a larger detrimental effect on unfolding than sequential mutants. For a more stable substrate (superfolder GFP), unfolding is overall slower, and multiple simultaneous mutations essentially prevent unfolding. Our results highlight the context-dependent need for grip during unfolding, support the hand-over-hand model for substrate unfolding and translocation, and suggest that for hard-to-unfold substrates, it is important to have simultaneous strong contacts to the substrate for unfolding to occur. The results also suggest a kinetic proofreading model, where substrates that cannot be easily unfolded are instead clipped, removing the initiation region and preventing futile unfolding attempts.
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Affiliation(s)
- Destini A Stanton
- Department of Chemistry, Villanova University, Villanova, PA, 19085, USA
| | - Emily A Ellis
- Department of Chemistry, Villanova University, Villanova, PA, 19085, USA
| | - Mariah R Cruse
- Department of Chemistry, Villanova University, Villanova, PA, 19085, USA
| | - Rafael Jedlinski
- Department of Chemistry, Villanova University, Villanova, PA, 19085, USA
| | - Daniel A Kraut
- Department of Chemistry, Villanova University, Villanova, PA, 19085, USA.
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22
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Pan Y, Zhan J, Jiang Y, Xia D, Scheuring S. A concerted ATPase cycle of the protein transporter AAA-ATPase Bcs1. Nat Commun 2023; 14:6369. [PMID: 37821516 PMCID: PMC10567702 DOI: 10.1038/s41467-023-41806-5] [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: 03/16/2023] [Accepted: 09/18/2023] [Indexed: 10/13/2023] Open
Abstract
Bcs1, a homo-heptameric transmembrane AAA-ATPase, facilitates folded Rieske iron-sulfur protein translocation across the inner mitochondrial membrane. Structures in different nucleotide states (ATPγS, ADP, apo) provided conformational snapshots, but the kinetics and structural transitions of the ATPase cycle remain elusive. Here, using high-speed atomic force microscopy (HS-AFM) and line scanning (HS-AFM-LS), we characterized single-molecule Bcs1 ATPase cycling. While the ATP conformation had ~5600 ms lifetime, independent of the ATP-concentration, the ADP/apo conformation lifetime was ATP-concentration dependent and reached ~320 ms at saturating ATP-concentration, giving a maximum turnover rate of 0.17 s-1. Importantly, Bcs1 ATPase cycle conformational changes occurred in concert. Furthermore, we propose that the transport mechanism involves opening the IMS gate through energetically costly straightening of the transmembrane helices, potentially driving rapid gate resealing. Overall, our results establish a concerted ATPase cycle mechanism in Bcs1, distinct from other AAA-ATPases that use a hand-over-hand mechanism.
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Affiliation(s)
- Yangang Pan
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY, USA
| | - Jingyu Zhan
- Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Yining Jiang
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY, USA
- Biochemistry & Structural Biology, Cell & Developmental Biology, and Molecular Biology (BCMB) Program, Weill Cornell Graduate School of Biomedical Sciences, New York, USA
| | - Di Xia
- Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Simon Scheuring
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY, USA.
- Department of Physiology & Biophysics, Weill Cornell Medical College, New York, NY, USA.
- Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, NY, USA.
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23
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Wald J, Marlovits TC. Holliday junction branch migration driven by AAA+ ATPase motors. Curr Opin Struct Biol 2023; 82:102650. [PMID: 37604043 DOI: 10.1016/j.sbi.2023.102650] [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: 03/20/2023] [Revised: 06/09/2023] [Accepted: 06/11/2023] [Indexed: 08/23/2023]
Abstract
Holliday junctions are key intermediate DNA structures during genetic recombination. One of the first Holliday junction-processing protein complexes to be discovered was the well conserved RuvAB branch migration complex present in bacteria that mediates an ATP-dependent movement of the Holliday junction (branch migration). Although the RuvAB complex served as a paradigm for the processing of the Holliday junction, due to technical limitations the detailed structure and underlying mechanism of the RuvAB branch migration complex has until now remained unclear. Recently, structures of a reconstituted RuvAB complex actively-processing a Holliday junction were resolved using time-resolved cryo-electron microscopy. These structures showed distinct conformational states at different stages of the migration process. These structures made it possible to propose an integrated model for RuvAB Holliday junction branch migration. Furthermore, they revealed unexpected insights into the highly coordinated and regulated mechanisms of the nucleotide cycle powering substrate translocation in the hexameric AAA+ RuvB ATPase. Here, we review these latest advances and describe areas for future research.
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Affiliation(s)
- Jiri Wald
- Centre for Structural Systems Biology, Notkestraße 85, 22607 Hamburg, Germany; Institute of Structural and Systems Biology, University Medical Center Hamburg-Eppendorf, Notkestraße 85, 22607 Hamburg, Germany; Deutsches Elektronen Synchrotron (DESY), Notkestraße 85, 22607 Hamburg, Germany
| | - Thomas C Marlovits
- Centre for Structural Systems Biology, Notkestraße 85, 22607 Hamburg, Germany; Institute of Structural and Systems Biology, University Medical Center Hamburg-Eppendorf, Notkestraße 85, 22607 Hamburg, Germany; Deutsches Elektronen Synchrotron (DESY), Notkestraße 85, 22607 Hamburg, Germany.
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24
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Rüttermann M, Koci M, Lill P, Geladas ED, Kaschani F, Klink BU, Erdmann R, Gatsogiannis C. Structure of the peroxisomal Pex1/Pex6 ATPase complex bound to a substrate. Nat Commun 2023; 14:5942. [PMID: 37741838 PMCID: PMC10518020 DOI: 10.1038/s41467-023-41640-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 09/12/2023] [Indexed: 09/25/2023] Open
Abstract
The double-ring AAA+ ATPase Pex1/Pex6 is required for peroxisomal receptor recycling and is essential for peroxisome formation. Pex1/Pex6 mutations cause severe peroxisome associated developmental disorders. Despite its pathophysiological importance, mechanistic details of the heterohexamer are not yet available. Here, we report cryoEM structures of Pex1/Pex6 from Saccharomyces cerevisiae, with an endogenous protein substrate trapped in the central pore of the catalytically active second ring (D2). Pairs of Pex1/Pex6(D2) subdomains engage the substrate via a staircase of pore-1 loops with distinct properties. The first ring (D1) is catalytically inactive but undergoes significant conformational changes resulting in alternate widening and narrowing of its pore. These events are fueled by ATP hydrolysis in the D2 ring and disengagement of a "twin-seam" Pex1/Pex6(D2) heterodimer from the staircase. Mechanical forces are propagated in a unique manner along Pex1/Pex6 interfaces that are not available in homo-oligomeric AAA-ATPases. Our structural analysis reveals the mechanisms of how Pex1 and Pex6 coordinate to achieve substrate translocation.
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Affiliation(s)
- Maximilian Rüttermann
- Institute for Medical Physics and Biophysics, University Münster, Münster, Germany
- Center for Soft Nanoscience (SoN), University Münster, Münster, Germany
| | - Michelle Koci
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Pascal Lill
- Institute for Medical Physics and Biophysics, University Münster, Münster, Germany
- Center for Soft Nanoscience (SoN), University Münster, Münster, Germany
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Ermis Dionysios Geladas
- Institute for Medical Physics and Biophysics, University Münster, Münster, Germany
- Center for Soft Nanoscience (SoN), University Münster, Münster, Germany
| | - Farnusch Kaschani
- Analytics Core Facility Essen, Center of Medical Biotechnology (ZMB), Faculty of Biology, University of Duisburg-Essen, Essen, Germany
| | - Björn Udo Klink
- Institute for Medical Physics and Biophysics, University Münster, Münster, Germany
- Center for Soft Nanoscience (SoN), University Münster, Münster, Germany
| | - Ralf Erdmann
- Institute for Biochemistry and Pathobiochemistry, Department of Systems Biochemistry, Ruhr-University Bochum, Bochum, Germany
| | - Christos Gatsogiannis
- Institute for Medical Physics and Biophysics, University Münster, Münster, Germany.
- Center for Soft Nanoscience (SoN), University Münster, Münster, Germany.
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany.
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25
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Ali BA, Judy RM, Chowdhury S, Jacobsen NK, Castanzo DT, Carr KL, Richardson CD, Lander GC, Martin A, Gardner BM. The Pex6 N1 domain is required for Pex15 binding and proper assembly with Pex1. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.15.557798. [PMID: 37745580 PMCID: PMC10516024 DOI: 10.1101/2023.09.15.557798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
The heterohexameric AAA-ATPase Pex1/Pex6 is essential for the formation and maintenance of peroxisomes. Pex1/Pex6, similar to other AAA-ATPases, uses the energy from ATP hydrolysis to mechanically thread substrate proteins through its central pore, thereby unfolding them. In related AAA-ATPase motors, substrates are recruited through binding to the motor's N-terminal domains or N-terminally bound co-factors. Here we use structural and biochemical techniques to characterize the function of the N1 domain in Pex6 from budding yeast, S. cerevisiae. We found that although Pex1/ΔN1-Pex6 is an active ATPase in vitro, it does not support Pex1/Pex6 function at the peroxisome in vivo. An X-ray crystal structure of the isolated Pex6 N1 domain shows that the Pex6 N1 domain shares the same fold as the N terminal domains of PEX1, CDC48, or NSF, despite poor sequence conservation. Integrating this structure with a cryo-EM reconstruction of Pex1/Pex6, AlphaFold2 predictions, and biochemical assays shows that Pex6 N1 mediates binding to both the peroxisomal membrane tether Pex15 and an extended loop from the D2 ATPase domain of Pex1 that influences Pex1/Pex6 heterohexamer stability. Given the direct interactions with both Pex15 and the D2 ATPase domains, the Pex6 N1 domain is poised to coordinate binding of co-factors and substrates with Pex1/Pex6 ATPase activity.
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Affiliation(s)
- Bashir A Ali
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA, USA
| | - Ryan M Judy
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA, USA
| | - Saikat Chowdhury
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
- Department of Biochemistry and Cell Biology, Stony Brook University, 100 Nicolls Road, Stony Brook, NY 11794, USA
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, Telangana 500007, India. Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India
| | - Nicole K Jacobsen
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA, USA
| | - Dominic T Castanzo
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Kaili L Carr
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Chris D Richardson
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA, USA
| | - Gabriel C Lander
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, 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
| | - Brooke M Gardner
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA, USA
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26
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Abstract
Peroxisomes are involved in a multitude of metabolic and catabolic pathways, as well as the innate immune system. Their dysfunction is linked to severe peroxisome-specific diseases, as well as cancer and neurodegenerative diseases. To ensure the ability of peroxisomes to fulfill their many roles in the organism, more than 100 different proteins are post-translationally imported into the peroxisomal membrane and matrix, and their functionality must be closely monitored. In this Review, we briefly discuss the import of peroxisomal membrane proteins, and we emphasize an updated view of both classical and alternative peroxisomal matrix protein import pathways. We highlight different quality control pathways that ensure the degradation of dysfunctional peroxisomal proteins. Finally, we compare peroxisomal matrix protein import with other systems that transport folded proteins across membranes, in particular the twin-arginine translocation (Tat) system and the nuclear pore.
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Affiliation(s)
- Markus Rudowitz
- Systems Biochemistry , Institute of Biochemistry and Pathobiochemistry, Faculty of Medicine, Ruhr University Bochum, Universitätsstr. 150, 44801 Bochum, Germany
| | - Ralf Erdmann
- Systems Biochemistry , Institute of Biochemistry and Pathobiochemistry, Faculty of Medicine, Ruhr University Bochum, Universitätsstr. 150, 44801 Bochum, Germany
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27
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Rish AD, Shen Z, Chen Z, Zhang N, Zheng Q, Fu TM. Molecular mechanisms of Holliday junction branch migration catalyzed by an asymmetric RuvB hexamer. Nat Commun 2023; 14:3549. [PMID: 37322069 PMCID: PMC10272136 DOI: 10.1038/s41467-023-39250-6] [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: 09/22/2022] [Accepted: 06/01/2023] [Indexed: 06/17/2023] Open
Abstract
The Holliday junction (HJ) is a DNA intermediate of homologous recombination, involved in many fundamental physiological processes. RuvB, an ATPase motor protein, drives branch migration of the Holliday junction with a mechanism that had yet to be elucidated. Here we report two cryo-EM structures of RuvB, providing a comprehensive understanding of HJ branch migration. RuvB assembles into a spiral staircase, ring-like hexamer, encircling dsDNA. Four protomers of RuvB contact the DNA backbone with a translocation step size of 2 nucleotides. The variation of nucleotide-binding states in RuvB supports a sequential model for ATP hydrolysis and nucleotide recycling, which occur at separate, singular positions. RuvB's asymmetric assembly also explains the 6:4 stoichiometry between the RuvB/RuvA complex, which coordinates HJ migration in bacteria. Taken together, we provide a mechanistic understanding of HJ branch migration facilitated by RuvB, which may be universally shared by prokaryotic and eukaryotic organisms.
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Affiliation(s)
- Anthony D Rish
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, OH, 43210, USA
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, 43210, USA
- Center for Cancer Metabolism, The Ohio State University Comprehensive Cancer Center, Columbus, OH, 43210, USA
| | - Zhangfei Shen
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, 43210, USA
- Center for Cancer Metabolism, The Ohio State University Comprehensive Cancer Center, Columbus, OH, 43210, USA
| | - Zhenhang Chen
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, 43210, USA
- Center for Cancer Metabolism, The Ohio State University Comprehensive Cancer Center, Columbus, OH, 43210, USA
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Nan Zhang
- Center for Cancer Metabolism, The Ohio State University Comprehensive Cancer Center, Columbus, OH, 43210, USA
- Department of Radiation Oncology, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Qingfei Zheng
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, OH, 43210, USA
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, 43210, USA
- Center for Cancer Metabolism, The Ohio State University Comprehensive Cancer Center, Columbus, OH, 43210, USA
- Department of Radiation Oncology, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Tian-Min Fu
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, OH, 43210, USA.
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, 43210, USA.
- Center for Cancer Metabolism, The Ohio State University Comprehensive Cancer Center, Columbus, OH, 43210, USA.
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28
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Abstract
Internal motions in proteins take place on a broad range of time- and space-scales. The potential roles of these dynamics in the biochemical functions of proteins have intrigued biophysicists for many years, and multiple mechanisms to couple motions to function have been proposed. Some of these mechanisms have relied on equilibrium concepts. For example, the modulation of dynamics was proposed to change the entropy of a protein, hence affecting processes such as binding. This so-called dynamic allostery scenario has been demonstrated in several recent experiments. Perhaps even more intriguing may be models that involve out-of-equilibrium operation, which by necessity require the input of energy. We discuss several recent experimental studies that expose such potential mechanisms for coupling dynamics and function. In Brownian ratchets, for example, directional motion is promoted by switching a protein between two free energy surfaces. An additional example involves the effect of microsecond domain-closure dynamics of an enzyme on its much slower chemical cycle. These observations lead us to propose a novel two-time-scale paradigm for the activity of protein machines: fast equilibrium fluctuations take place on the microsecond-millisecond time scale, while on a slower time scale, free energy is invested in order to push the system out of equilibrium and drive functional transitions. Motions on the two time scales affect each other and are essential for the overall function of these machines.
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Affiliation(s)
- Gilad Haran
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Inbal Riven
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 7610001, Israel
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29
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Gupta A, Lentzsch AM, Siegel A, Yu Z, Chio US, Cheng Y, Shan SO. Dodecamer assembly of a metazoan AAA + chaperone couples substrate extraction to refolding. SCIENCE ADVANCES 2023; 9:eadf5336. [PMID: 37163603 PMCID: PMC10171807 DOI: 10.1126/sciadv.adf5336] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 04/04/2023] [Indexed: 05/12/2023]
Abstract
Ring-forming AAA+ chaperones solubilize protein aggregates and protect organisms from proteostatic stress. In metazoans, the AAA+ chaperone Skd3 in the mitochondrial intermembrane space (IMS) is critical for human health and efficiently refolds aggregated proteins, but its underlying mechanism is poorly understood. Here, we show that Skd3 harbors both disaggregase and protein refolding activities enabled by distinct assembly states. High-resolution structures of Skd3 hexamers in distinct conformations capture ratchet-like motions that mediate substrate extraction. Unlike previously described disaggregases, Skd3 hexamers further assemble into dodecameric cages in which solubilized substrate proteins can attain near-native states. Skd3 mutants defective in dodecamer assembly retain disaggregase activity but are impaired in client refolding, linking the disaggregase and refolding activities to the hexameric and dodecameric states of Skd3, respectively. We suggest that Skd3 is a combined disaggregase and foldase, and this property is particularly suited to meet the complex proteostatic demands in the mitochondrial IMS.
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Affiliation(s)
- Arpit Gupta
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Alfred M. Lentzsch
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Alex Siegel
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Zanlin Yu
- Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, CA 94158, USA
| | - Un Seng Chio
- Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, CA 94158, USA
| | - Yifan Cheng
- Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, CA 94158, USA
- Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, CA 94158, USA
| | - Shu-ou Shan
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
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30
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Valimehr S, Sethi A, Shukla M, Bhattacharyya S, Kazemi M, Rouiller I. Molecular Mechanisms Driving and Regulating the AAA+ ATPase VCP/p97, an Important Therapeutic Target for Treating Cancer, Neurological and Infectious Diseases. Biomolecules 2023; 13:biom13050737. [PMID: 37238606 DOI: 10.3390/biom13050737] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 03/15/2023] [Accepted: 04/13/2023] [Indexed: 05/28/2023] Open
Abstract
p97/VCP, a highly conserved type II ATPase associated with diverse cellular activities (AAA+ ATPase), is an important therapeutic target in the treatment of neurodegenerative diseases and cancer. p97 performs a variety of functions in the cell and facilitates virus replication. It is a mechanochemical enzyme that generates mechanical force from ATP-binding and hydrolysis to perform several functions, including unfolding of protein substrates. Several dozens of cofactors/adaptors interact with p97 and define the multifunctionality of p97. This review presents the current understanding of the molecular mechanism of p97 during the ATPase cycle and its regulation by cofactors and small-molecule inhibitors. We compare detailed structural information obtained in different nucleotide states in the presence and absence of substrates and inhibitors. We also review how pathogenic gain-of-function mutations modify the conformational changes of p97 during the ATPase cycle. Overall, the review highlights how the mechanistic knowledge of p97 helps in designing pathway-specific modulators and inhibitors.
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Affiliation(s)
- Sepideh Valimehr
- Department of Biochemistry & Pharmacology, The University of Melbourne, Melbourne, VIC 3010, Australia
- Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC 3010, Australia
- Bio21 Ian Holmes Imaging Centre, Department of Biochemistry & Pharmacology, The University of Melbourne, Melbourne, VIC 3010, Australia
- ARC Centre for Cryo-Electron Microscopy of Membrane Proteins, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Ashish Sethi
- Department of Biochemistry & Pharmacology, The University of Melbourne, Melbourne, VIC 3010, Australia
- Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC 3010, Australia
- Australian Nuclear Science Technology Organisation, The Australian Synchrotron, 800 Blackburn Rd, Clayton, VIC 3168, Australia
| | - Manjari Shukla
- Department of Bioscience and Bioengineering, Indian Institute of Technology Jodhpur, Jodhpur 342030, Rajasthan, India
| | - Sudipta Bhattacharyya
- Department of Bioscience and Bioengineering, Indian Institute of Technology Jodhpur, Jodhpur 342030, Rajasthan, India
| | - Mohsen Kazemi
- Department of Biochemistry & Pharmacology, The University of Melbourne, Melbourne, VIC 3010, Australia
- Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC 3010, Australia
- ARC Centre for Cryo-Electron Microscopy of Membrane Proteins, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Isabelle Rouiller
- Department of Biochemistry & Pharmacology, The University of Melbourne, Melbourne, VIC 3010, Australia
- Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC 3010, Australia
- ARC Centre for Cryo-Electron Microscopy of Membrane Proteins, The University of Melbourne, Melbourne, VIC 3010, Australia
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31
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Kelly MS, Macke AC, Kahawatte S, Stump JE, Miller AR, Dima RI. The quaternary question: Determining allostery in spastin through dynamics classification learning and bioinformatics. J Chem Phys 2023; 158:125102. [PMID: 37003743 DOI: 10.1063/5.0139273] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023] Open
Abstract
The nanomachine from the ATPases associated with various cellular activities superfamily, called spastin, severs microtubules during cellular processes. To characterize the functionally important allostery in spastin, we employed methods from evolutionary information, to graph-based networks, to machine learning applied to atomistic molecular dynamics simulations of spastin in its monomeric and the functional hexameric forms, in the presence or absence of ligands. Feature selection, using machine learning approaches, for transitions between spastin states recognizes all the regions that have been proposed as allosteric or functional in the literature. The analysis of the composition of the Markov State Model macrostates in the spastin monomer, and the analysis of the direction of change in the top machine learning features for the transitions, indicate that the monomer favors the binding of ATP, which primes the regions involved in the formation of the inter-protomer interfaces for binding to other protomer(s). Allosteric path analysis of graph networks, built based on the cross-correlations between residues in simulations, shows that perturbations to a hub specific for the pre-hydrolysis hexamer propagate throughout the structure by passing through two obligatory regions: the ATP binding pocket, and pore loop 3, which connects the substrate binding site to the ATP binding site. Our findings support a model where the changes in the terminal protomers due to the binding of ligands play an active role in the force generation in spastin. The secondary structures in spastin, which are found to be highly degenerative within the network paths, are also critical for feature transitions of the classification models, which can guide the design of allosteric effectors to enhance or block allosteric signaling.
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Affiliation(s)
- Maria S Kelly
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, USA
| | - Amanda C Macke
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, USA
| | - Shehani Kahawatte
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, USA
| | - Jacob E Stump
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, USA
| | - Abigail R Miller
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, USA
| | - Ruxandra I Dima
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, USA
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32
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Zhan J, Xia D. Bcs1, a novel target for fungicide. Front Chem 2023; 11:1146753. [PMID: 36993815 PMCID: PMC10040684 DOI: 10.3389/fchem.2023.1146753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 03/03/2023] [Indexed: 03/14/2023] Open
Abstract
The mitochondrial respiratory chain has long been a primary target for the development of fungicides for its indispensable role in various cellular functions including energy metabolism. Over the years, a wide range of natural and synthetic fungicides and pesticides targeting the respiratory chain complexes have been discovered or developed and used in agriculture and in medicine, which brought considerable economic gains but was also accompanied by the emergence of resistance to these compounds. To delay and overcome the onset of resistance, novel targets for fungicides development are actively being pursued. Mitochondrial AAA protein Bcs1 is necessary for the biogenesis of respiratory chain Complex III, also known as cyt bc1 complex, by delivering the last essential iron-sulfur protein subunit in its folded form to the cyt bc1 precomplex. Although no report on the phenotypes of knock-out Bcs1 has been reported in animals, pathogenic Bcs1 mutations cause Complex III deficiency and respiratory growth defects, which makes it a promising new target for the development of fungicides. Recent Cryo-EM and X-ray structures of mouse and yeast Bcs1 revealed the basic oligomeric states of Bcs1, shed light on the translocation mechanism of its substrate ISP, and provided the basis for structure-based drug design. This review summarizes the recent progress made on understanding the structure and function of Bcs1, proposes the use of Bcs1 as an antifungal target, and provides novel prospects for fungicides design by targeting Bcs1.
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Waheeda K, Kitchel H, Wang Q, Chiu PL. Molecular mechanism of Rubisco activase: Dynamic assembly and Rubisco remodeling. Front Mol Biosci 2023; 10:1125922. [PMID: 36845545 PMCID: PMC9951593 DOI: 10.3389/fmolb.2023.1125922] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 01/31/2023] [Indexed: 02/12/2023] Open
Abstract
Ribulose-1,5-bisphosphate (RuBP) carboxylase-oxygenase (Rubisco) enzyme is the limiting step of photosynthetic carbon fixation, and its activation is regulated by its co-evolved chaperone, Rubisco activase (Rca). Rca removes the intrinsic sugar phosphate inhibitors occupying the Rubisco active site, allowing RuBP to split into two 3-phosphoglycerate (3PGA) molecules. This review summarizes the evolution, structure, and function of Rca and describes the recent findings regarding the mechanistic model of Rubisco activation by Rca. New knowledge in these areas can significantly enhance crop engineering techniques used to improve crop productivity.
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Affiliation(s)
- Kazi Waheeda
- School of Molecular Sciences, Arizona State University, Tempe, AZ, United States
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, AZ, United States
| | - Heidi Kitchel
- School of Molecular Sciences, Arizona State University, Tempe, AZ, United States
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, AZ, United States
| | - Quan Wang
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Po-Lin Chiu
- School of Molecular Sciences, Arizona State University, Tempe, AZ, United States
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, AZ, United States
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Wu D, Liu Y, Dai Y, Wang G, Lu G, Chen Y, Li N, Lin J, Gao N. Comprehensive structural characterization of the human AAA+ disaggregase CLPB in the apo- and substrate-bound states reveals a unique mode of action driven by oligomerization. PLoS Biol 2023; 21:e3001987. [PMID: 36745679 PMCID: PMC9934407 DOI: 10.1371/journal.pbio.3001987] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 02/16/2023] [Accepted: 01/04/2023] [Indexed: 02/07/2023] Open
Abstract
The human AAA+ ATPase CLPB (SKD3) is a protein disaggregase in the mitochondrial intermembrane space (IMS) and functions to promote the solubilization of various mitochondrial proteins. Loss-of-function CLPB mutations are associated with a few human diseases with neutropenia and neurological disorders. Unlike canonical AAA+ proteins, CLPB contains a unique ankyrin repeat domain (ANK) at its N-terminus. How CLPB functions as a disaggregase and the role of its ANK domain are currently unclear. Herein, we report a comprehensive structural characterization of human CLPB in both the apo- and substrate-bound states. CLPB assembles into homo-tetradecamers in apo-state and is remodeled into homo-dodecamers upon substrate binding. Conserved pore-loops (PLs) on the ATPase domains form a spiral staircase to grip and translocate the substrate in a step-size of 2 amino acid residues. The ANK domain is not only responsible for maintaining the higher-order assembly but also essential for the disaggregase activity. Interactome analysis suggests that the ANK domain may directly interact with a variety of mitochondrial substrates. These results reveal unique properties of CLPB as a general disaggregase in mitochondria and highlight its potential as a target for the treatment of various mitochondria-related diseases.
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Affiliation(s)
- Damu Wu
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing, China
| | - Yan Liu
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yuhao Dai
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing, China
- Academy of Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Guopeng Wang
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing, China
| | - Guoliang Lu
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yan Chen
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing, China
| | - Ningning Li
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing, China
- Changping Laboratory, Beijing, China
| | - Jinzhong Lin
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Zhongshan Hospital, Fudan University, Shanghai, China
- * E-mail: (JL); (NG)
| | - Ning Gao
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing, China
- Changping Laboratory, Beijing, China
- National Biomedical Imaging Center, Peking University, Beijing, China
- * E-mail: (JL); (NG)
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Mukherjee S, Mepperi J, Sahu P, Barman DK, Kotamarthi HC. Single-Molecule Optical Tweezers As a Tool for Delineating the Mechanisms of Protein-Processing Mechanoenzymes. ACS OMEGA 2023; 8:87-97. [PMID: 36643560 PMCID: PMC9835622 DOI: 10.1021/acsomega.2c06044] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 12/06/2022] [Indexed: 06/17/2023]
Abstract
Mechanoenzymes convert chemical energy from the hydrolysis of nucleotide triphosphates to mechanical energy for carrying out cellular functions ranging from DNA unwinding to protein degradation. Protein-processing mechanoenzymes either remodel the protein structures or translocate them across cellular compartments in an energy-dependent manner. Optical-tweezer-based single-molecule force spectroscopy assays have divulged information on details of chemo-mechanical coupling, directed motion, as well as mechanical forces these enzymes are capable of generating. In this review, we introduce the working principles of optical tweezers as a single-molecule force spectroscopy tool and assays developed to decipher the properties such as unfolding kinetics, translocation velocities, and step sizes by protein remodeling mechanoenzymes. We focus on molecular motors involved in protein degradation and disaggregation, i.e., ClpXP, ClpAP, and ClpB, and insights provided by single-molecule assays on kinetics and stepping dynamics during protein unfolding and translocation. Cellular activities such as protein synthesis, folding, and translocation across membranes are also energy dependent, and the recent single-molecule studies decoding the role of mechanical forces on these processes have been discussed.
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36
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Macke AC, Kelly MS, Varikoti RA, Mullen S, Groves D, Forbes C, Dima RI. Microtubule Severing Enzymes Oligomerization and Allostery: A Tale of Two Domains. J Phys Chem B 2022; 126:10569-10586. [PMID: 36475672 DOI: 10.1021/acs.jpcb.2c05288] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Severing proteins are nanomachines from the AAA+ (ATPases associated with various cellular activities) superfamily whose function is to remodel the largest cellular filaments, microtubules. The standard AAA+ machines adopt hexameric ring structures for functional reasons, while being primarily monomeric in the absence of the nucleotide. Both major severing proteins, katanin and spastin, are believed to follow this trend. However, studies proposed that they populate lower-order oligomers in the presence of cofactors, which are functionally relevant. Our simulations show that the preferred oligomeric assembly is dependent on the binding partners and on the type of severing protein. Essential dynamics analysis predicts that the stability of an oligomer is dependent on the strength of the interface between the helical bundle domain (HBD) of a monomer and the convex face of the nucleotide binding domain (NBD) of a neighboring monomer. Hot spots analysis found that the region consisting of the HBD tip and the C-terminal (CT) helix is the only common element between the allosteric networks responding to nucleotide, substrate, and intermonomer binding. Clustering analysis indicates the existence of multiple pathways for the transition between the secondary structure of the HBD tip in monomers and the structure(s) it adopts in oligomers.
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Affiliation(s)
- Amanda C Macke
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Maria S Kelly
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Rohith Anand Varikoti
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Sarah Mullen
- Department of Chemistry, The College of Wooster, Wooster, Ohio 44691, United States
- Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Daniel Groves
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Clare Forbes
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Ruxandra I Dima
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
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37
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Lee G, Kim RS, Lee SB, Lee S, Tsai FT. Deciphering the mechanism and function of Hsp100 unfoldases from protein structure. Biochem Soc Trans 2022; 50:1725-1736. [PMID: 36454589 PMCID: PMC9784670 DOI: 10.1042/bst20220590] [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: 10/10/2022] [Revised: 11/11/2022] [Accepted: 11/15/2022] [Indexed: 12/02/2022]
Abstract
Hsp100 chaperones, also known as Clp proteins, constitute a family of ring-forming ATPases that differ in 3D structure and cellular function from other stress-inducible molecular chaperones. While the vast majority of ATP-dependent molecular chaperones promote the folding of either the nascent chain or a newly imported polypeptide to reach its native conformation, Hsp100 chaperones harness metabolic energy to perform the reverse and facilitate the unfolding of a misfolded polypeptide or protein aggregate. It is now known that inside cells and organelles, different Hsp100 members are involved in rescuing stress-damaged proteins from a previously aggregated state or in recycling polypeptides marked for degradation. Protein degradation is mediated by a barrel-shaped peptidase that physically associates with the Hsp100 hexamer to form a two-component system. Notable examples include the ClpA:ClpP (ClpAP) and ClpX:ClpP (ClpXP) proteases that resemble the ring-forming FtsH and Lon proteases, which unlike ClpAP and ClpXP, feature the ATP-binding and proteolytic domains in a single polypeptide chain. Recent advances in electron cryomicroscopy (cryoEM) together with single-molecule biophysical studies have now provided new mechanistic insight into the structure and function of this remarkable group of macromolecular machines.
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Affiliation(s)
- Grace Lee
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030, USA
- Rice University, Houston, Texas 77005, USA
| | - Rebecca S. Kim
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Sang Bum Lee
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Sukyeong Lee
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030, USA
- Advanced Technology Core for Macromolecular X-ray Crystallography, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Francis T.F. Tsai
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030, USA
- Advanced Technology Core for Macromolecular X-ray Crystallography, Baylor College of Medicine, Houston, Texas 77030, USA
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030, USA
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas 77030, USA
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38
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SV40 T-antigen uses a DNA shearing mechanism to initiate origin unwinding. Proc Natl Acad Sci U S A 2022; 119:e2216240119. [PMID: 36442086 PMCID: PMC9894130 DOI: 10.1073/pnas.2216240119] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Duplication of DNA genomes requires unwinding of the double-strand (ds) DNA so that each single strand (ss) can be copied by a DNA polymerase. The genomes of eukaryotic cells are unwound by two ring-shaped hexameric helicases that initially encircle dsDNA but transition to ssDNA for function as replicative helicases. How the duplex is initially unwound, and the role of the two helicases in this process, is poorly understood. We recently described an initiation mechanism for eukaryotes in which the two helicases are directed inward toward one another and shear the duplex open by pulling on opposite strands of the duplex while encircling dsDNA [L. D. Langston, M. E. O'Donnell, eLife 8, e46515 (2019)]. Two head-to-head T-Antigen helicases are long known to be loaded at the SV40 origin. We show here that T-Antigen tracks head (N-tier) first on ssDNA, opposite the direction proposed for decades. We also find that SV40 T-Antigen tracks directionally while encircling dsDNA and mainly tracks on one strand of the duplex in the same orientation as during ssDNA translocation. Further, two inward directed T-Antigen helicases on dsDNA are able to melt a 150-bp duplex. These findings explain the "rabbit ear" DNA loops observed at the SV40 origin by electron microscopy and reconfigure how the DNA loops emerge from the double hexamer relative to earlier models. Thus, the mechanism of DNA shearing by two opposing helicases is conserved in a eukaryotic viral helicase and may be widely used to initiate origin unwinding of dsDNA genomes.
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Ma C, Wu D, Chen Q, Gao N. Structural dynamics of AAA + ATPase Drg1 and mechanism of benzo-diazaborine inhibition. Nat Commun 2022; 13:6765. [PMID: 36351914 PMCID: PMC9646744 DOI: 10.1038/s41467-022-34511-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 10/27/2022] [Indexed: 11/11/2022] Open
Abstract
The type II AAA + ATPase Drg1 is a ribosome assembly factor, functioning to release Rlp24 from the pre-60S particle just exported from nucleus, and its activity in can be inhibited by a drug molecule diazaborine. However, molecular mechanisms of Drg1-mediated Rlp24 removal and diazaborine-mediated inhibition are not fully understood. Here, we report Drg1 structures in different nucleotide-binding and benzo-diazaborine treated states. Drg1 hexamers transits between two extreme conformations (planar or helical arrangement of protomers). By forming covalent adducts with ATP molecules in both ATPase domain, benzo-diazaborine locks Drg1 hexamers in a symmetric and non-productive conformation to inhibits both inter-protomer and inter-ring communication of Drg1 hexamers. We also obtained a substrate-engaged mutant Drg1 structure, in which conserved pore-loops form a spiral staircase to interact with the polypeptide through a sequence-independent manner. Structure-based mutagenesis data highlight the functional importance of the pore-loop, the D1-D2 linker and the inter-subunit signaling motif of Drg1, which share similar regulatory mechanisms with p97. Our results suggest that Drg1 may function as an unfoldase that threads a substrate protein within the pre-60S particle.
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Affiliation(s)
- Chengying Ma
- grid.11135.370000 0001 2256 9319State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, 100871 Beijing, China ,Changping Laboratory, 102206 Beijing, China
| | - Damu Wu
- grid.11135.370000 0001 2256 9319State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, 100871 Beijing, China
| | - Qian Chen
- grid.11135.370000 0001 2256 9319State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, 100871 Beijing, China
| | - Ning Gao
- grid.11135.370000 0001 2256 9319State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, 100871 Beijing, China ,Changping Laboratory, 102206 Beijing, China ,grid.11135.370000 0001 2256 9319National Biomedical Imaging Center, Peking University, 100871 Beijing, China
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40
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Kocaman S, Lo YH, Krahn JM, Sobhany M, Dandey VP, Petrovich ML, Etigunta SK, Williams JG, Deterding LJ, Borgnia MJ, Stanley RE. Communication network within the essential AAA-ATPase Rix7 drives ribosome assembly. PNAS NEXUS 2022; 1:pgac118. [PMID: 36090660 PMCID: PMC9437592 DOI: 10.1093/pnasnexus/pgac118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/08/2022] [Indexed: 02/06/2023]
Abstract
Rix7 is an essential AAA+ ATPase that functions during the early stages of ribosome biogenesis. Rix7 is composed of three domains including an N-terminal domain (NTD) and two AAA+ domains (D1 and D2) that assemble into an asymmetric stacked hexamer. It was recently established that Rix7 is a presumed protein translocase that removes substrates from preribosomes by translocating them through its central pore. However, how the different domains of Rix7 coordinate their activities within the overall hexameric structure was unknown. We captured cryo-electron microscopy (EM) structures of single and double Walker B variants of full length Rix7. The disordered NTD was not visible in the cryo-EM reconstructions, but cross-linking mass spectrometry revealed that the NTD can associate with the central channel in vitro. Deletion of the disordered NTD enabled us to obtain a structure of the Rix7 hexamer to 2.9 Å resolution, providing high resolution details of critical motifs involved in substrate translocation and interdomain communication. This structure coupled with cell-based assays established that the linker connecting the D1 and D2 domains as well as the pore loops lining the central channel are essential for formation of the large ribosomal subunit. Together, our work shows that Rix7 utilizes a complex communication network to drive ribosome biogenesis.
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Affiliation(s)
- Seda Kocaman
- Department of Health and Human Services, Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Yu-Hua Lo
- Department of Health and Human Services, Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Juno M Krahn
- Department of Health and Human Services, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Mack Sobhany
- Department of Health and Human Services, Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Venkata P Dandey
- Department of Health and Human Services, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Matthew L Petrovich
- Department of Health and Human Services, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Suhas K Etigunta
- Department of Health and Human Services, Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Jason G Williams
- Department of Health and Human Services, Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Leesa J Deterding
- Department of Health and Human Services, Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Mario J Borgnia
- Department of Health and Human Services, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Robin E Stanley
- Department of Health and Human Services, Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
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Wald J, Fahrenkamp D, Goessweiner-Mohr N, Lugmayr W, Ciccarelli L, Vesper O, Marlovits TC. Mechanism of AAA+ ATPase-mediated RuvAB-Holliday junction branch migration. Nature 2022; 609:630-639. [PMID: 36002576 PMCID: PMC9477746 DOI: 10.1038/s41586-022-05121-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 07/18/2022] [Indexed: 12/12/2022]
Abstract
The Holliday junction is a key intermediate formed during DNA recombination across all kingdoms of life1. In bacteria, the Holliday junction is processed by two homo-hexameric AAA+ ATPase RuvB motors, which assemble together with the RuvA-Holliday junction complex to energize the strand-exchange reaction2. Despite its importance for chromosome maintenance, the structure and mechanism by which this complex facilitates branch migration are unknown. Here, using time-resolved cryo-electron microscopy, we obtained structures of the ATP-hydrolysing RuvAB complex in seven distinct conformational states, captured during assembly and processing of a Holliday junction. Five structures together resolve the complete nucleotide cycle and reveal the spatiotemporal relationship between ATP hydrolysis, nucleotide exchange and context-specific conformational changes in RuvB. Coordinated motions in a converter formed by DNA-disengaged RuvB subunits stimulate hydrolysis and nucleotide exchange. Immobilization of the converter enables RuvB to convert the ATP-contained energy into a lever motion, which generates the pulling force driving the branch migration. We show that RuvB motors rotate together with the DNA substrate, which, together with a progressing nucleotide cycle, forms the mechanistic basis for DNA recombination by continuous branch migration. Together, our data decipher the molecular principles of homologous recombination by the RuvAB complex, elucidate discrete and sequential transition-state intermediates for chemo-mechanical coupling of hexameric AAA+ motors and provide a blueprint for the design of state-specific compounds targeting AAA+ motors.
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Affiliation(s)
- Jiri Wald
- Institute of Structural and Systems Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
- Centre for Structural Systems Biology, Hamburg, Germany.
- Deutsches Elektronen Synchrotron (DESY), Hamburg, Germany.
- Institute of Molecular Biotechnology GmbH (IMBA), Austrian Academy of Sciences, Vienna, Austria.
- Research Institute of Molecular Pathology (IMP), Vienna, Austria.
| | - Dirk Fahrenkamp
- Institute of Structural and Systems Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
- Centre for Structural Systems Biology, Hamburg, Germany.
- Deutsches Elektronen Synchrotron (DESY), Hamburg, Germany.
| | - Nikolaus Goessweiner-Mohr
- Institute of Structural and Systems Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany
- Deutsches Elektronen Synchrotron (DESY), Hamburg, Germany
- Institute of Molecular Biotechnology GmbH (IMBA), Austrian Academy of Sciences, Vienna, Austria
- Research Institute of Molecular Pathology (IMP), Vienna, Austria
- Institute of Biophysics, Johannes Kepler University (JKU), Linz, Austria
| | - Wolfgang Lugmayr
- Institute of Structural and Systems Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany
- Deutsches Elektronen Synchrotron (DESY), Hamburg, Germany
- Institute of Molecular Biotechnology GmbH (IMBA), Austrian Academy of Sciences, Vienna, Austria
- Research Institute of Molecular Pathology (IMP), Vienna, Austria
| | - Luciano Ciccarelli
- Institute of Structural and Systems Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany
- Institute of Molecular Biotechnology GmbH (IMBA), Austrian Academy of Sciences, Vienna, Austria
- Research Institute of Molecular Pathology (IMP), Vienna, Austria
- GlaxoSmithKline Vaccines, Siena, Italy
| | - Oliver Vesper
- Institute of Structural and Systems Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany
- Deutsches Elektronen Synchrotron (DESY), Hamburg, Germany
- Institute of Molecular Biotechnology GmbH (IMBA), Austrian Academy of Sciences, Vienna, Austria
- Research Institute of Molecular Pathology (IMP), Vienna, Austria
| | - Thomas C Marlovits
- Institute of Structural and Systems Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
- Centre for Structural Systems Biology, Hamburg, Germany.
- Deutsches Elektronen Synchrotron (DESY), Hamburg, Germany.
- Institute of Molecular Biotechnology GmbH (IMBA), Austrian Academy of Sciences, Vienna, Austria.
- Research Institute of Molecular Pathology (IMP), Vienna, Austria.
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Prattes M, Grishkovskaya I, Hodirnau VV, Hetzmannseder C, Zisser G, Sailer C, Kargas V, Loibl M, Gerhalter M, Kofler L, Warren AJ, Stengel F, Haselbach D, Bergler H. Visualizing maturation factor extraction from the nascent ribosome by the AAA-ATPase Drg1. Nat Struct Mol Biol 2022; 29:942-953. [PMID: 36097293 PMCID: PMC9507969 DOI: 10.1038/s41594-022-00832-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 08/03/2022] [Indexed: 11/23/2022]
Abstract
The AAA-ATPase Drg1 is a key factor in eukaryotic ribosome biogenesis that initiates cytoplasmic maturation of the large ribosomal subunit. Drg1 releases the shuttling maturation factor Rlp24 from pre-60S particles shortly after nuclear export, a strict requirement for downstream maturation. The molecular mechanism of release remained elusive. Here, we report a series of cryo-EM structures that captured the extraction of Rlp24 from pre-60S particles by Saccharomyces cerevisiae Drg1. These structures reveal that Arx1 and the eukaryote-specific rRNA expansion segment ES27 form a joint docking platform that positions Drg1 for efficient extraction of Rlp24 from the pre-ribosome. The tips of the Drg1 N domains thereby guide the Rlp24 C terminus into the central pore of the Drg1 hexamer, enabling extraction by a hand-over-hand translocation mechanism. Our results uncover substrate recognition and processing by Drg1 step by step and provide a comprehensive mechanistic picture of the conserved modus operandi of AAA-ATPases.
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Affiliation(s)
- Michael Prattes
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Irina Grishkovskaya
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter, Vienna, Austria
| | | | | | - Gertrude Zisser
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Carolin Sailer
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Vasileios Kargas
- Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Cambridge, UK
- Wellcome Trust-Medical Research Council Stem Cell Institute, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, Cambridge, UK
- Department of Haematology, University of Cambridge School of Clinical Medicine, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, Cambridge, UK
| | - Mathias Loibl
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | | | - Lisa Kofler
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Alan J Warren
- Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Cambridge, UK
- Wellcome Trust-Medical Research Council Stem Cell Institute, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, Cambridge, UK
- Department of Haematology, University of Cambridge School of Clinical Medicine, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, Cambridge, UK
| | - Florian Stengel
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - David Haselbach
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter, Vienna, Austria.
| | - Helmut Bergler
- Institute of Molecular Biosciences, University of Graz, Graz, Austria.
- BioTechMed-Graz, Graz, Austria.
- Field of Excellence BioHealth - University of Graz, Graz, Austria.
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43
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Cooperativity in ATP Hydrolysis by MopR Is Modulated by Its Signal Reception Domain and by Its Protein and Phenol Concentrations. J Bacteriol 2022; 204:e0017922. [PMID: 35862728 PMCID: PMC9380524 DOI: 10.1128/jb.00179-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The NtrC family of AAA+ proteins are bacterial transcriptional regulators that control σ54-dependent RNA polymerase transcription under certain stressful conditions. MopR, which is a member of this family, is responsive to phenol and stimulates its degradation. Biochemical studies to understand the role of ATP and phenol in oligomerization and allosteric regulation, which are described here, show that MopR undergoes concentration-dependent oligomerization in which dimers assemble into functional hexamers. The oligomerization occurs in a nucleation-dependent manner with a tetrameric intermediate. Additionally, phenol binding is shown to be responsible for shifting MopR's equilibrium from a repressed state (high affinity toward ATP) to a functionally active, derepressed state with low-affinity for ATP. Based on these findings, we propose a model for allosteric regulation of MopR. IMPORTANCE The NtrC family of bacterial transcriptional regulators are enzymes with a modular architecture that harbor a signal sensing domain followed by a AAA+ domain. MopR, a NtrC family member, responds to phenol and activates phenol adaptation pathways that are transcribed by σ54-dependent RNA polymerases. Our results show that for efficient ATP hydrolysis, MopR assembles as functional hexamers and that this activity of MopR is regulated by its effector (phenol), ATP, and protein concentration. Our findings, and the kinetic methods we employ, should be useful in dissecting the allosteric mechanisms of other AAA+ proteins, in general, and NtrC family members in particular.
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44
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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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45
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Sharma N, Osman C. Yme2, a putative RNA recognition motif and AAA+ domain containing protein, genetically interacts with the mitochondrial protein export machinery. Biol Chem 2022; 403:807-817. [PMID: 35100666 PMCID: PMC9284673 DOI: 10.1515/hsz-2021-0398] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 01/19/2022] [Indexed: 02/04/2023]
Abstract
The mitochondrial respiratory chain is composed of nuclear as well as mitochondrial-encoded subunits. A variety of factors mediate co-translational integration of mtDNA-encoded proteins into the inner membrane. In Saccharomyces cerevisiae, Mdm38 and Mba1 are ribosome acceptors that recruit the mitochondrial ribosome to the inner membrane, where the insertase Oxa1, facilitates membrane integration of client proteins. The protein Yme2 has previously been shown to be localized in the inner mitochondrial membrane and has been implicated in mitochondrial protein biogenesis, but its mode of action remains unclear. Here, we show that multiple copies of Yme2 assemble into a high molecular weight complex. Using a combination of bioinformatics and mutational analyses, we find that Yme2 possesses an RNA recognition motif (RRM), which faces the mitochondrial matrix and a AAA+ domain that is located in the intermembrane space. We further show that YME2 genetically interacts with MDM38, MBA1 and OXA1, which links the function of Yme2 to the mitochondrial protein biogenesis machinery.
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Affiliation(s)
- Nupur Sharma
- Faculty of Biology, Ludwig Maximilian University Munich, D-82152Planegg-Martinsried, Germany
- Graduate School of Life Sciences, Ludwig Maximilian University Munich, D-82152Planegg-Martinsried, Germany
| | - Christof Osman
- Faculty of Biology, Ludwig Maximilian University Munich, D-82152Planegg-Martinsried, Germany
- Graduate School of Life Sciences, Ludwig Maximilian University Munich, D-82152Planegg-Martinsried, Germany
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46
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Judy RM, Sheedy CJ, Gardner BM. Insights into the Structure and Function of the Pex1/Pex6 AAA-ATPase in Peroxisome Homeostasis. Cells 2022; 11:2067. [PMID: 35805150 PMCID: PMC9265785 DOI: 10.3390/cells11132067] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 06/25/2022] [Accepted: 06/26/2022] [Indexed: 02/01/2023] Open
Abstract
The AAA-ATPases Pex1 and Pex6 are required for the formation and maintenance of peroxisomes, membrane-bound organelles that harbor enzymes for specialized metabolism. Together, Pex1 and Pex6 form a heterohexameric AAA-ATPase capable of unfolding substrate proteins via processive threading through a central pore. Here, we review the proposed roles for Pex1/Pex6 in peroxisome biogenesis and degradation, discussing how the unfolding of potential substrates contributes to peroxisome homeostasis. We also consider how advances in cryo-EM, computational structure prediction, and mechanisms of related ATPases are improving our understanding of how Pex1/Pex6 converts ATP hydrolysis into mechanical force. Since mutations in PEX1 and PEX6 cause the majority of known cases of peroxisome biogenesis disorders such as Zellweger syndrome, insights into Pex1/Pex6 structure and function are important for understanding peroxisomes in human health and disease.
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Affiliation(s)
| | | | - Brooke M. Gardner
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA 93106, USA; (R.M.J.); (C.J.S.)
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47
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Taylor G, Frommherz Y, Katikaridis P, Layer D, Sinning I, Carroni M, Weber-Ban E, Mogk A. Antibacterial peptide CyclomarinA creates toxicity by deregulating the Mycobacterium tuberculosis ClpC1/ClpP1P2 protease. J Biol Chem 2022; 298:102202. [PMID: 35768046 PMCID: PMC9305358 DOI: 10.1016/j.jbc.2022.102202] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 06/16/2022] [Accepted: 06/17/2022] [Indexed: 11/18/2022] Open
Abstract
The ring-forming AAA+ hexamer ClpC1 associates with the peptidase ClpP1P2 to form a central, ATP-driven protease in Mycobacterium tuberculosis (Mtb). ClpC1 is essential for Mtb viability and has been identified as the target of antibacterial peptides like CyclomarinA (CymA) that exhibit strong toxicity towards Mtb. The mechanistic actions of these drugs are poorly understood, but seem diverse, as they have different effects on ClpC1's ATPase and proteolytic activities. Here, we dissected how ClpC1 activity is controlled and how this control is deregulated by CymA. We show that ClpC1 exists in diverse activity states correlating with its assembly. The basal activity of ClpC1 is low, as it predominantly exists in an inactive, non-hexameric resting state. We show CymA stimulates ClpC1 activity by promoting formation of super-complexes composed of multiple ClpC1 hexameric rings, enhancing ClpC1/ClpP1P2 degradation activity towards a diverse range of substrates. Both the ClpC1 resting state and the CymA-induced alternative assembly state rely on interactions between the ClpC1 coiled-coil middle domains (MDs). Accordingly, we found mutation of the conserved aromatic F444 residue located at the MD tip blocks MD interactions and prevents assembly into higher order complexes, thereby leading to constitutive ClpC1 hexamer formation. We demonstrate this assembly state exhibits the highest ATPase and proteolytic activities, yet its heterologous expression in Escherichia coli is toxic, indicating that the formation of such a state must be tightly controlled. Taken together, these findings define the basis of control of ClpC1 activity and show how ClpC1 overactivation by an antibacterial drug generates toxicity.
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Affiliation(s)
- Gabrielle Taylor
- ETH Zurich, Institute of Molecular Biology and Biophysics, Zurich, Switzerland
| | - Yannick Frommherz
- Center for Molecular Biology of the University of Heidelberg (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany; Division of Chaperones and Proteases, Division of Chaperones and Proteases, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany
| | - Panagiotis Katikaridis
- Center for Molecular Biology of the University of Heidelberg (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany; Division of Chaperones and Proteases, Division of Chaperones and Proteases, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany
| | - Dominik Layer
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany
| | - Irmgard Sinning
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany
| | - Marta Carroni
- Swedish Cryo-EM Facility, Science for Life Laboratory Stockholm University, Solna, Sweden
| | - Eilika Weber-Ban
- ETH Zurich, Institute of Molecular Biology and Biophysics, Zurich, Switzerland.
| | - Axel Mogk
- Center for Molecular Biology of the University of Heidelberg (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany; Division of Chaperones and Proteases, Division of Chaperones and Proteases, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany.
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48
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Lin J, Shorter J, Lucius AL. AAA+ proteins: one motor, multiple ways to work. Biochem Soc Trans 2022; 50:895-906. [PMID: 35356966 PMCID: PMC9115847 DOI: 10.1042/bst20200350] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 03/14/2022] [Accepted: 03/15/2022] [Indexed: 12/15/2022]
Abstract
Numerous ATPases associated with diverse cellular activities (AAA+) proteins form hexameric, ring-shaped complexes that function via ATPase-coupled translocation of substrates across the central channel. Cryo-electron microscopy of AAA+ proteins processing substrate has revealed non-symmetric, staircase-like hexameric structures that indicate a sequential clockwise/2-residue step translocation model for these motors. However, for many of the AAA+ proteins that share similar structural features, their translocation properties have not yet been experimentally determined. In the cases where translocation mechanisms have been determined, a two-residue translocation step-size has not been resolved. In this review, we explore Hsp104, ClpB, ClpA and ClpX as examples to review the experimental methods that have been used to examine, in solution, the translocation mechanisms employed by AAA+ motor proteins. We then ask whether AAA+ motors sharing similar structural features can have different translocation mechanisms. Finally, we discuss whether a single AAA+ motor can adopt multiple translocation mechanisms that are responsive to different challenges imposed by the substrate or the environment. We suggest that AAA+ motors adopt more than one translocation mechanism and are tuned to switch to the most energetically efficient mechanism when constraints are applied.
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Affiliation(s)
- JiaBei Lin
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, U.S.A
| | - James Shorter
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, U.S.A
| | - Aaron L. Lucius
- Department of Chemistry, University of Alabama at Birmingham, Birmingham, AL, U.S.A
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49
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Cryo-EM structure of transmembrane AAA+ protease FtsH in the ADP state. Commun Biol 2022; 5:257. [PMID: 35322207 PMCID: PMC8943139 DOI: 10.1038/s42003-022-03213-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 03/01/2022] [Indexed: 11/08/2022] Open
Abstract
AAA+ proteases regulate numerous physiological and cellular processes through tightly regulated proteolytic cleavage of protein substrates driven by ATP hydrolysis. FtsH is the only known family of membrane-anchored AAA+ proteases essential for membrane protein quality control. Although a spiral staircase rotation mechanism for substrate translocation across the FtsH pore has been proposed, the detailed conformational changes among various states have not been clear due to absence of FtsH structures in these states. We report here the cryo-EM structure for Thermotoga maritima FtsH (TmFtsH) in a fully ADP-bound symmetric state. Comparisons of the ADP-state structure with its apo-state and a substrate-engaged yeast YME1 structure show conformational changes in the ATPase domains, rather than the protease domains. A reconstruction of the full-length TmFtsH provides structural insights for the dynamic transmembrane and the periplasmic domains. Our structural analyses expand the understanding of conformational switches between different nucleotide states in ATP hydrolysis by FtsH.
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50
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Mabanglo MF, Houry WA. Recent structural insights into the mechanism of ClpP protease regulation by AAA+ chaperones and small molecules. J Biol Chem 2022; 298:101781. [PMID: 35245501 PMCID: PMC9035409 DOI: 10.1016/j.jbc.2022.101781] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 02/17/2022] [Accepted: 02/18/2022] [Indexed: 11/19/2022] Open
Abstract
ClpP is a highly conserved serine protease that is a critical enzyme in maintaining protein homeostasis and is an important drug target in pathogenic bacteria and various cancers. In its functional form, ClpP is a self-compartmentalizing protease composed of two stacked heptameric rings that allow protein degradation to occur within the catalytic chamber. ATPase chaperones such as ClpX and ClpA are hexameric ATPases that form larger complexes with ClpP and are responsible for the selection and unfolding of protein substrates prior to their degradation by ClpP. Although individual structures of ClpP and ATPase chaperones have offered mechanistic insights into their function and regulation, their structures together as a complex have only been recently determined to high resolution. Here, we discuss the cryoelectron microscopy structures of ClpP-ATPase complexes and describe findings previously inaccessible from individual Clp structures, including how a hexameric ATPase and a tetradecameric ClpP protease work together in a functional complex. We then discuss the consensus mechanism for substrate unfolding and translocation derived from these structures, consider alternative mechanisms, and present their strengths and limitations. Finally, new insights into the allosteric control of ClpP gained from studies using small molecules and gain or loss-of-function mutations are explored. Overall, this review aims to underscore the multilayered regulation of ClpP that may present novel ideas for structure-based drug design.
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Affiliation(s)
- Mark F Mabanglo
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Walid A Houry
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada; Department of Chemistry, University of Toronto, Toronto, Ontario, Canada.
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