1
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Mack KL, Kim H, Barbieri EM, Lin J, Braganza S, Jackrel ME, DeNizio JE, Yan X, Chuang E, Tariq A, Cupo RR, Castellano LM, Caldwell KA, Caldwell GA, Shorter J. Tuning Hsp104 specificity to selectively detoxify α-synuclein. Mol Cell 2023; 83:3314-3332.e9. [PMID: 37625404 PMCID: PMC10530207 DOI: 10.1016/j.molcel.2023.07.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 07/19/2023] [Accepted: 07/28/2023] [Indexed: 08/27/2023]
Abstract
Hsp104 is an AAA+ protein disaggregase that solubilizes and reactivates proteins trapped in aggregated states. We have engineered potentiated Hsp104 variants to mitigate toxic misfolding of α-synuclein, TDP-43, and FUS implicated in fatal neurodegenerative disorders. Though potent disaggregases, these enhanced Hsp104 variants lack substrate specificity and can have unfavorable off-target effects. Here, to lessen off-target effects, we engineer substrate-specific Hsp104 variants. By altering Hsp104 pore loops that engage substrate, we disambiguate Hsp104 variants that selectively suppress α-synuclein toxicity but not TDP-43 or FUS toxicity. Remarkably, α-synuclein-specific Hsp104 variants emerge that mitigate α-synuclein toxicity via distinct ATPase-dependent mechanisms involving α-synuclein disaggregation or detoxification of soluble α-synuclein conformers. Importantly, both types of α-synuclein-specific Hsp104 variant reduce dopaminergic neurodegeneration in a C. elegans model of Parkinson's disease more effectively than non-specific variants. We suggest that increasing the substrate specificity of enhanced disaggregases could be applied broadly to tailor therapeutics for neurodegenerative disease.
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Affiliation(s)
- Korrie L Mack
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Hanna Kim
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - Edward M Barbieri
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - JiaBei Lin
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Sylvanne Braganza
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Meredith E Jackrel
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jamie E DeNizio
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Xiaohui Yan
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - Edward Chuang
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Pharmacology Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Amber Tariq
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ryan R Cupo
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Pharmacology Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Laura M Castellano
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kim A Caldwell
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - Guy A Caldwell
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL 35487, USA.
| | - James Shorter
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Pharmacology Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.
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2
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Neves-da-Rocha J, Santos-Saboya MJ, Lopes MER, Rossi A, Martinez-Rossi NM. Insights and Perspectives on the Role of Proteostasis and Heat Shock Proteins in Fungal Infections. Microorganisms 2023; 11:1878. [PMID: 37630438 PMCID: PMC10456932 DOI: 10.3390/microorganisms11081878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 06/30/2023] [Accepted: 07/06/2023] [Indexed: 08/27/2023] Open
Abstract
Fungi are a diverse group of eukaryotic organisms that infect humans, animals, and plants. To successfully colonize their hosts, pathogenic fungi must continuously adapt to the host's unique environment, e.g., changes in temperature, pH, and nutrient availability. Appropriate protein folding, assembly, and degradation are essential for maintaining cellular homeostasis and survival under stressful conditions. Therefore, the regulation of proteostasis is crucial for fungal pathogenesis. The heat shock response (HSR) is one of the most important cellular mechanisms for maintaining proteostasis. It is activated by various stresses and regulates the activity of heat shock proteins (HSPs). As molecular chaperones, HSPs participate in the proteostatic network to control cellular protein levels by affecting their conformation, location, and degradation. In recent years, a growing body of evidence has highlighted the crucial yet understudied role of stress response circuits in fungal infections. This review explores the role of protein homeostasis and HSPs in fungal pathogenicity, including their contributions to virulence and host-pathogen interactions, as well as the concerted effects between HSPs and the main proteostasis circuits in the cell. Furthermore, we discuss perspectives in the field and the potential for targeting the components of these circuits to develop novel antifungal therapies.
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Affiliation(s)
- João Neves-da-Rocha
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14049-900, SP, Brazil; (M.J.S.-S.); (M.E.R.L.); (A.R.)
| | | | | | | | - Nilce M. Martinez-Rossi
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14049-900, SP, Brazil; (M.J.S.-S.); (M.E.R.L.); (A.R.)
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3
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Knier AS, Davis EE, Buchholz HE, Dorweiler JE, Flannagan LE, Manogaran AL. The yeast molecular chaperone, Hsp104, influences transthyretin aggregate formation. Front Mol Neurosci 2022; 15:1050472. [PMID: 36590917 PMCID: PMC9802906 DOI: 10.3389/fnmol.2022.1050472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 10/19/2022] [Indexed: 12/23/2022] Open
Abstract
Patients with the fatal disorder Transthyretin Amyloidosis (ATTR) experience polyneuropathy through the progressive destruction of peripheral nervous tissue. In these patients, the transthyretin (TTR) protein dissociates from its functional tetrameric structure, misfolds, and aggregates into extracellular amyloid deposits that are associated with disease progression. These aggregates form large fibrillar structures as well as shorter oligomeric aggregates that are suspected to be cytotoxic. Several studies have shown that these extracellular TTR aggregates enter the cell and accumulate intracellularly, which is associated with increased proteostasis response. However, there are limited experimental models to study how proteostasis influences internalized TTR aggregates. Here, we use a humanized yeast system to recapitulate intracellular TTR aggregating protein in vivo. The yeast molecular chaperone Hsp104 is a disaggregase that has been shown to fragment amyloidogenic aggregates associated with certain yeast prions and reduce protein aggregation associated with human neurogenerative diseases. In yeast, we found that TTR forms both SDS-resistant oligomers and SDS-sensitive large molecular weight complexes. In actively dividing cultures, Hsp104 has no impact on oligomeric or large aggregate populations, yet overexpression of Hsp104 is loosely associated with an increase in overall aggregate size. Interestingly, a potentiating mutation in the middle domain of Hsp104 consistently results in an increase in overall TTR aggregate size. These data suggest a novel approach to aggregate management, where the Hsp104 variant shifts aggregate populations away from toxic oligomeric species to more inert larger aggregates. In aged cultures Hsp104 overexpression has no impact on TTR aggregation profiles suggesting that these chaperone approaches to shift aggregate populations are not effective with age, possibly due to proteostasis decline.
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4
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Cupo RR, Rizo AN, Braun GA, Tse E, Chuang E, Gupta K, Southworth DR, Shorter J. Unique structural features govern the activity of a human mitochondrial AAA+ disaggregase, Skd3. Cell Rep 2022; 40:111408. [PMID: 36170828 PMCID: PMC9584538 DOI: 10.1016/j.celrep.2022.111408] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 06/02/2022] [Accepted: 09/01/2022] [Indexed: 11/27/2022] Open
Abstract
The AAA+ protein, Skd3 (human CLPB), solubilizes proteins in the mitochondrial intermembrane space, which is critical for human health. Skd3 variants with defective protein-disaggregase activity cause severe congenital neutropenia (SCN) and 3-methylglutaconic aciduria type 7 (MGCA7). How Skd3 disaggregates proteins remains poorly understood. Here, we report a high-resolution structure of a Skd3-substrate complex. Skd3 adopts a spiral hexameric arrangement that engages substrate via pore-loop interactions in the nucleotide-binding domain (NBD). Substrate-bound Skd3 hexamers stack head-to-head via unique, adaptable ankyrin-repeat domain (ANK)-mediated interactions to form dodecamers. Deleting the ANK linker region reduces dodecamerization and disaggregase activity. We elucidate apomorphic features of the Skd3 NBD and C-terminal domain that regulate disaggregase activity. We also define how Skd3 subunits collaborate to disaggregate proteins. Importantly, SCN-linked subunits sharply inhibit disaggregase activity, whereas MGCA7-linked subunits do not. These advances illuminate Skd3 structure and mechanism, explain SCN and MGCA7 inheritance patterns, and suggest therapeutic strategies.
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Affiliation(s)
- Ryan R Cupo
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA, USA; Pharmacology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Alexandrea N Rizo
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA; Graduate Program in Chemical Biology, University of Michigan, Ann Arbor, MI, USA
| | - Gabriel A Braun
- Chemistry and Chemical Biology Graduate Program, Institute for Neurodegenerative Diseases, University of California, San Francisco, San Francisco, CA, USA
| | - Eric Tse
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA
| | - Edward Chuang
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA, USA; Pharmacology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Kushol Gupta
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA, USA
| | - Daniel R Southworth
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA.
| | - James Shorter
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA, USA; Pharmacology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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5
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Riven I, Mazal H, Iljina M, Haran G. Fast dynamics shape the function of the
AAA
+ machine
ClpB
: lessons from single‐molecule
FRET
spectroscopy. FEBS J 2022. [DOI: 10.1111/febs.16539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 05/04/2022] [Accepted: 05/30/2022] [Indexed: 12/01/2022]
Affiliation(s)
- Inbal Riven
- 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
| | - Marija Iljina
- 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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6
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AAA+ proteins: one motor, multiple ways to work. Biochem Soc Trans 2022; 50:895-906. [PMID: 35356966 DOI: 10.1042/bst20200350] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [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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7
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Ryan JJ, Bao A, Bell B, Ling C, Jackrel ME. Drivers of Hsp104 potentiation revealed by scanning mutagenesis of the middle domain. Protein Sci 2021; 30:1667-1685. [PMID: 34010483 DOI: 10.1002/pro.4126] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 05/11/2021] [Accepted: 05/18/2021] [Indexed: 01/03/2023]
Abstract
Hsp104, a yeast protein disaggregase, can be potentiated via numerous missense mutations at disparate locations throughout the coiled-coil middle domain (MD). Potentiated Hsp104 variants can counter the toxicity and misfolding of TDP-43, FUS, and α-synuclein, proteins which are implicated in neurodegenerative disorders. However, potentiated MD variants typically exhibit off-target toxicity. Further, it has remained confounding how numerous degenerate mutations confer potentiation, hampering engineering of therapeutic Hsp104 variants. Here, we sought to comprehensively define the key drivers of Hsp104 potentiation. Using scanning mutagenesis, we iteratively studied the effects of modulation at each position in the Hsp104 MD. Screening this library to identify enhanced variants reveals that missense mutations at 26% of positions in the MD yield variants that counter FUS toxicity. Modulation of the helix 2-helix 3/4 MD interface potentiates Hsp104, whereas mutations in the analogous helix 1-2 interface do not. Surprisingly, we find that there is a higher likelihood of enhancing Hsp104 activity against human disease substrates than impairing Hsp104 native function. We find that single mutations can broadly destabilize the MD structure and lead to functional potentiation, suggesting this may be a common mechanism conferring Hsp104 potentiation. Using this approach, we have demonstrated that modulation of the MD can yield engineered variants with decreased off-target effects.
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Affiliation(s)
- Jeremy J Ryan
- Department of Chemistry, Washington University, St. Louis, Missouri, USA
| | - Aaron Bao
- Department of Chemistry, Washington University, St. Louis, Missouri, USA
| | - Braxton Bell
- Department of Chemistry, Washington University, St. Louis, Missouri, USA
| | - Cendi Ling
- Department of Chemistry, Washington University, St. Louis, Missouri, USA
| | - Meredith E Jackrel
- Department of Chemistry, Washington University, St. Louis, Missouri, USA
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8
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Glynn SE, Kardon JR, Mueller-Cajar O, Cho C. AAA+ proteins: converging mechanisms, diverging functions. Nat Struct Mol Biol 2020; 27:515-518. [PMID: 32461632 DOI: 10.1038/s41594-020-0444-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Steven E Glynn
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, USA.
| | - Julia R Kardon
- Department of Biochemistry, Brandeis University, Waltham, MA, USA.
| | - Oliver Mueller-Cajar
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.
| | - Carol Cho
- Research Center for Natural Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea.
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9
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Scull NW, Lucius AL. Kinetic Analysis of AAA+ Translocases by Combined Fluorescence and Anisotropy Methods. Biophys J 2020; 119:1335-1350. [PMID: 32997959 DOI: 10.1016/j.bpj.2020.08.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 08/03/2020] [Accepted: 08/17/2020] [Indexed: 11/30/2022] Open
Abstract
The multitude of varied, energy-dependent processes that exist in the cell necessitate a diverse array of macromolecular machines to maintain homeostasis, allow for growth, and facilitate reproduction. ATPases associated with various cellular activity are a set of protein assemblies that function as molecular motors to couple the energy of nucleoside triphosphate binding and hydrolysis to mechanical movement along a polymer lattice. A recent boom in structural insights into these motors has led to structural hypotheses on how these motors fulfill their function. However, in many cases, we lack direct kinetic measurements of the dynamic processes these motors undergo as they transition between observed structural states. Consequently, there is a need for improved techniques for testing the structural hypotheses in solution. Here, we apply transient-state fluorescence anisotropy and total fluorescence stopped-flow methods to the analysis of polypeptide translocation catalyzed by these ATPase motors. We specifically focus on the Hsp100-Clp protein system of ClpA, which is a well-studied, model ATPases associated with various cellular activity system that has both eukaryotic and archaea homologs. Using this system, we show that we can reproduce previously established kinetic parameters from the simultaneous analysis of fluorescence anisotropy and total fluorescence and overcome previous limitations of our previous approach. Specifically, for the first time, to our knowledge, we obtain quantitative interpretations of the translocation of polypeptide substrates longer than 100 aa.
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Affiliation(s)
- Nathaniel W Scull
- Department of Chemistry, University of Alabama at Birmingham, Birmingham, Alabama
| | - Aaron L Lucius
- Department of Chemistry, University of Alabama at Birmingham, Birmingham, Alabama.
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10
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Structural and kinetic basis for the regulation and potentiation of Hsp104 function. Proc Natl Acad Sci U S A 2020; 117:9384-9392. [PMID: 32277033 DOI: 10.1073/pnas.1921968117] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Hsp104 provides a valuable model for the many essential proteostatic functions performed by the AAA+ superfamily of protein molecular machines. We developed and used a powerful hydrogen exchange mass spectrometry (HX MS) analysis that can provide positionally resolved information on structure, dynamics, and energetics of the Hsp104 molecular machinery, even during functional cycling. HX MS reveals that the ATPase cycle is rate-limited by ADP release from nucleotide-binding domain 1 (NBD1). The middle domain (MD) serves to regulate Hsp104 activity by slowing ADP release. Mutational potentiation accelerates ADP release, thereby increasing ATPase activity. It reduces time in the open state, thereby decreasing substrate protein loss. During active cycling, Hsp104 transits repeatedly between whole hexamer closed and open states. Under diverse conditions, the shift of open/closed balance can lead to premature substrate loss, normal processing, or the generation of a strong pulling force. HX MS exposes the mechanisms of these functions at near-residue resolution.
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11
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Sweeny EA, Tariq A, Gurpinar E, Go MS, Sochor MA, Kan ZY, Mayne L, Englander SW, Shorter J. Structural and mechanistic insights into Hsp104 function revealed by synchrotron X-ray footprinting. J Biol Chem 2020; 295:1517-1538. [PMID: 31882541 PMCID: PMC7008382 DOI: 10.1074/jbc.ra119.011577] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 12/23/2019] [Indexed: 01/11/2023] Open
Abstract
Hsp104 is a hexameric AAA+ ring translocase, which drives protein disaggregation in nonmetazoan eukaryotes. Cryo-EM structures of Hsp104 have suggested potential mechanisms of substrate translocation, but precisely how Hsp104 hexamers disaggregate proteins remains incompletely understood. Here, we employed synchrotron X-ray footprinting to probe the solution-state structures of Hsp104 monomers in the absence of nucleotide and Hsp104 hexamers in the presence of ADP or ATPγS (adenosine 5'-O-(thiotriphosphate)). Comparing side-chain solvent accessibilities between these three states illuminated aspects of Hsp104 structure and guided design of Hsp104 variants to probe the disaggregase mechanism in vitro and in vivo We established that Hsp104 hexamers switch from a more-solvated state in ADP to a less-solvated state in ATPγS, consistent with switching from an open spiral to a closed ring visualized by cryo-EM. We pinpointed critical N-terminal domain (NTD), NTD-nucleotide-binding domain 1 (NBD1) linker, NBD1, and middle domain (MD) residues that enable intrinsic disaggregase activity and Hsp70 collaboration. We uncovered NTD residues in the loop between helices A1 and A2 that can be substituted to enhance disaggregase activity. We elucidated a novel potentiated Hsp104 MD variant, Hsp104-RYD, which suppresses α-synuclein, fused in sarcoma (FUS), and TDP-43 toxicity. We disambiguated a secondary pore-loop in NBD1, which collaborates with the NTD and NBD1 tyrosine-bearing pore-loop to drive protein disaggregation. Finally, we defined Leu-601 in NBD2 as crucial for Hsp104 hexamerization. Collectively, our findings unveil new facets of Hsp104 structure and mechanism. They also connect regions undergoing large changes in solvation to functionality, which could have profound implications for protein engineering.
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Affiliation(s)
- Elizabeth A Sweeny
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104; Biochemistry and Molecular Biophysics Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania 19104.
| | - Amber Tariq
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Esin Gurpinar
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Michelle S Go
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Matthew A Sochor
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104; Biochemistry and Molecular Biophysics Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Zhong-Yuan Kan
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104; Johnson Research Foundation, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Leland Mayne
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104; Johnson Research Foundation, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - S Walter Englander
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104; Biochemistry and Molecular Biophysics Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania 19104; Johnson Research Foundation, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - James Shorter
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104; Biochemistry and Molecular Biophysics Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania 19104.
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12
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Avellaneda MJ, Franke KB, Sunderlikova V, Bukau B, Mogk A, Tans SJ. Processive extrusion of polypeptide loops by a Hsp100 disaggregase. Nature 2020; 578:317-320. [PMID: 31996849 DOI: 10.1038/s41586-020-1964-y] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 12/03/2019] [Indexed: 01/13/2023]
Abstract
The ability to reverse protein aggregation is vital to cells1,2. Hsp100 disaggregases such as ClpB and Hsp104 are proposed to catalyse this reaction by translocating polypeptide loops through their central pore3,4. This model of disaggregation is appealing, as it could explain how polypeptides entangled within aggregates can be extracted and subsequently refolded with the assistance of Hsp704,5. However, the model is also controversial, as the necessary motor activity has not been identified6-8 and recent findings indicate non-processive mechanisms such as entropic pulling or Brownian ratcheting9,10. How loop formation would be accomplished is also obscure. Indeed, cryo-electron microscopy studies consistently show single polypeptide strands in the Hsp100 pore11,12. Here, by following individual ClpB-substrate complexes in real time, we unambiguously demonstrate processive translocation of looped polypeptides. We integrate optical tweezers with fluorescent-particle tracking to show that ClpB translocates both arms of the loop simultaneously and switches to single-arm translocation when encountering obstacles. ClpB is notably powerful and rapid; it exerts forces of more than 50 pN at speeds of more than 500 residues per second in bursts of up to 28 residues. Remarkably, substrates refold while exiting the pore, analogous to co-translational folding. Our findings have implications for protein-processing phenomena including ubiquitin-mediated remodelling by Cdc48 (or its mammalian orthologue p97)13 and degradation by the 26S proteasome14.
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Affiliation(s)
| | - Kamila B Franke
- Center for Molecular Biology of Heidelberg University, German Cancer Research Center, Heidelberg, Germany
| | | | - Bernd Bukau
- Center for Molecular Biology of Heidelberg University, German Cancer Research Center, Heidelberg, Germany
| | - Axel Mogk
- Center for Molecular Biology of Heidelberg University, German Cancer Research Center, Heidelberg, Germany
| | - Sander J Tans
- AMOLF, Amsterdam, The Netherlands. .,Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, The Netherlands.
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