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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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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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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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Shorter J, Southworth DR. Spiraling in Control: Structures and Mechanisms of the Hsp104 Disaggregase. Cold Spring Harb Perspect Biol 2019; 11:cshperspect.a034033. [PMID: 30745294 DOI: 10.1101/cshperspect.a034033] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Hsp104 is a hexameric AAA+ ATPase and protein disaggregase found in yeast, which couples ATP hydrolysis to the dissolution of diverse polypeptides trapped in toxic preamyloid oligomers, phase-transitioned gels, disordered aggregates, amyloids, and prions. Hsp104 shows plasticity in disaggregating diverse substrates, but how its hexameric architecture operates as a molecular machine has remained unclear. Here, we highlight structural advances made via cryoelectron microscopy (cryo-EM) that enhance our mechanistic understanding of Hsp104 and other related AAA+ translocases. Hsp104 hexamers are dynamic and adopt open "lock-washer" spiral states and closed ring structures that envelope polypeptide substrate inside the axial channel. ATP hydrolysis-driven conformational changes at the spiral seam ratchet substrate deeper into the channel. Remarkably, this mode of polypeptide translocation is reminiscent of models for how hexameric helicases unwind DNA and RNA duplexes. Thus, Hsp104 likely adapts elements of a deeply rooted, ring-translocase mechanism to the specialized task of protein disaggregation.
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Affiliation(s)
- James Shorter
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Daniel R Southworth
- Department of Biochemistry and Biophysics; and the Institute for Neurodegenerative Diseases, University of California San Francisco, San Francisco, California 94158
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Durie CL, Lin J, Scull NW, Mack KL, Jackrel ME, Sweeny EA, Castellano LM, Shorter J, Lucius AL. Hsp104 and Potentiated Variants Can Operate as Distinct Nonprocessive Translocases. Biophys J 2019; 116:1856-1872. [PMID: 31027887 DOI: 10.1016/j.bpj.2019.03.035] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 03/14/2019] [Accepted: 03/25/2019] [Indexed: 01/09/2023] Open
Abstract
Heat shock protein (Hsp) 104 is a hexameric ATPases associated with diverse cellular activities motor protein that enables cells to survive extreme stress. Hsp104 couples the energy of ATP binding and hydrolysis to solubilize proteins trapped in aggregated structures. The mechanism by which Hsp104 disaggregates proteins is not completely understood but may require Hsp104 to partially or completely translocate polypeptides across its central channel. Here, we apply transient state, single turnover kinetics to investigate the ATP-dependent translocation of soluble polypeptides by Hsp104 and Hsp104A503S, a potentiated variant developed to resolve misfolded conformers implicated in neurodegenerative disease. We establish that Hsp104 and Hsp104A503S can operate as nonprocessive translocases for soluble substrates, indicating a "partial threading" model of translocation. Remarkably, Hsp104A503S exhibits altered coupling of ATP binding to translocation and decelerated dissociation from polypeptide substrate compared to Hsp104. This altered coupling and prolonged substrate interaction likely increases entropic pulling forces, thereby enabling more effective aggregate dissolution by Hsp104A503S.
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Affiliation(s)
- Clarissa L Durie
- University of Alabama at Birmingham, Chemistry Department, Birmingham, Alabama
| | - JiaBei Lin
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Nathaniel W Scull
- University of Alabama at Birmingham, Chemistry Department, Birmingham, Alabama
| | - Korrie L Mack
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Meredith E Jackrel
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Elizabeth A Sweeny
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Laura M Castellano
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - James Shorter
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Aaron L Lucius
- University of Alabama at Birmingham, Chemistry Department, Birmingham, Alabama.
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Hydrogen exchange reveals Hsp104 architecture, structural dynamics, and energetics in physiological solution. Proc Natl Acad Sci U S A 2019; 116:7333-7342. [PMID: 30918129 DOI: 10.1073/pnas.1816184116] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Hsp104 is a large AAA+ molecular machine that can rescue proteins trapped in amorphous aggregates and stable amyloids by drawing substrate protein into its central pore. Recent cryo-EM studies image Hsp104 at high resolution. We used hydrogen exchange mass spectrometry analysis (HX MS) to resolve and characterize all of the functionally active and inactive elements of Hsp104, many not accessible to cryo-EM. At a global level, HX MS confirms the one noncanonical interprotomer interface in the Hsp104 hexamer as a marker for the spiraled conformation revealed by cryo-EM and measures its fast conformational cycling under ATP hydrolysis. Other findings enable reinterpretation of the apparent variability of the regulatory middle domain. With respect to detailed mechanism, HX MS determines the response of each Hsp104 structural element to the different bound adenosine nucleotides (ADP, ATP, AMPPNP, and ATPγS). They are distinguished most sensitively by the two Walker A nucleotide-binding segments. Binding of the ATP analog, ATPγS, tightly restructures the Walker A segments and drives the global open-to-closed/extended transition. The global transition carries part of the ATP/ATPγS-binding energy to the somewhat distant central pore. The pore constricts and the tyrosine and other pore-related loops become more tightly structured, which seems to reflect the energy-requiring directional pull that translocates the substrate protein. ATP hydrolysis to ADP allows Hsp104 to relax back to its lowest energy open state ready to restart the cycle.
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Durie CL, Duran EC, Lucius AL. Escherichia coli DnaK Allosterically Modulates ClpB between High- and Low-Peptide Affinity States. Biochemistry 2018; 57:3665-3675. [PMID: 29812913 DOI: 10.1021/acs.biochem.8b00045] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
ClpB and DnaKJE provide protection to Escherichia coli cells during extreme environmental stress. Together, this co-chaperone system can resolve protein aggregates, restoring misfolded proteins to their native form and function in solubilizing damaged proteins for removal by the cell's proteolytic systems. DnaK is the component of the KJE system that directly interacts with ClpB. There are many hypotheses for how DnaK affects ClpB-catalyzed disaggregation, each with some experimental support. Here, we build on our recent work characterizing the molecular mechanism of ClpB-catalyzed polypeptide translocation by developing a stopped-flow FRET assay that allows us to detect ClpB's movement on model polypeptide substrates in the absence or presence of DnaK. We find that DnaK induces ClpB to dissociate from the polypeptide substrate. We propose that DnaK acts as a peptide release factor, binding ClpB and causing the ClpB conformation to change to a low-peptide affinity state. Such a role for DnaK would allow ClpB to rebind to another portion of an aggregate and continue nonprocessive translocation to disrupt the aggregate.
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Affiliation(s)
- Clarissa L Durie
- Department of Chemistry , University of Alabama at Birmingham , Birmingham , Alabama 35294-1240 , United States
| | - Elizabeth C Duran
- Department of Chemistry , University of Alabama at Birmingham , Birmingham , Alabama 35294-1240 , United States
| | - Aaron L Lucius
- Department of Chemistry , University of Alabama at Birmingham , Birmingham , Alabama 35294-1240 , United States
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Duran EC, Weaver CL, Lucius AL. Comparative Analysis of the Structure and Function of AAA+ Motors ClpA, ClpB, and Hsp104: Common Threads and Disparate Functions. Front Mol Biosci 2017; 4:54. [PMID: 28824920 PMCID: PMC5540906 DOI: 10.3389/fmolb.2017.00054] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 07/13/2017] [Indexed: 11/25/2022] Open
Abstract
Cellular proteostasis involves not only the expression of proteins in response to environmental needs, but also the timely repair or removal of damaged or unneeded proteins. AAA+ motor proteins are critically involved in these pathways. Here, we review the structure and function of AAA+ proteins ClpA, ClpB, and Hsp104. ClpB and Hsp104 rescue damaged proteins from toxic aggregates and do not partner with any protease. ClpA functions as the regulatory component of the ATP dependent protease complex ClpAP, and also remodels inactive RepA dimers into active monomers in the absence of the protease. Because ClpA functions both with and without a proteolytic component, it is an ideal system for developing strategies that address one of the major challenges in the study of protein remodeling machines: how do we observe a reaction in which the substrate protein does not undergo covalent modification? Here, we review experimental designs developed for the examination of polypeptide translocation catalyzed by the AAA+ motors in the absence of proteolytic degradation. We propose that transient state kinetic methods are essential for the examination of elementary kinetic mechanisms of these motor proteins. Furthermore, rigorous kinetic analysis must also account for the thermodynamic properties of these complicated systems that reside in a dynamic equilibrium of oligomeric states, including the biologically active hexamer.
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Affiliation(s)
- Elizabeth C Duran
- Department of Chemistry, University of Alabama at BirminghamBirmingham, AL, United States
| | - Clarissa L Weaver
- Department of Chemistry, University of Alabama at BirminghamBirmingham, AL, United States
| | - Aaron L Lucius
- Department of Chemistry, University of Alabama at BirminghamBirmingham, AL, United States
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