1
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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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2
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Panagaki F, Tapia-Rojo R, Zhu T, Milmoe N, Paracuellos P, Board S, Mora M, Walker J, Rostkova E, Stannard A, Infante E, Garcia-Manyes S. Structural anisotropy results in mechano-directional transport of proteins across nuclear pores. NATURE PHYSICS 2024; 20:1180-1193. [PMID: 39036650 PMCID: PMC11254768 DOI: 10.1038/s41567-024-02438-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 02/08/2024] [Indexed: 07/23/2024]
Abstract
The nuclear pore complex regulates nucleocytoplasmic transport by means of a tightly synchronized suite of biochemical reactions. The physicochemical properties of the translocating cargos are emerging as master regulators of their shuttling dynamics. As well as being affected by molecular weight and surface-exposed amino acids, the kinetics of the nuclear translocation of protein cargos also depend on their nanomechanical properties, yet the mechanisms underpinning the mechanoselectivity of the nuclear pore complex are unclear. Here we show that proteins with locally soft regions in the vicinity of the nuclear-localization sequence exhibit higher nuclear-import rates, and that such mechanoselectivity is specifically impaired upon knocking down nucleoporin 153, a key protein in the nuclear pore complex. This allows us to design a short, easy-to-express and chemically inert unstructured peptide tag that accelerates the nuclear-import rate of stiff protein cargos. We also show that U2OS osteosarcoma cells expressing the peptide-tagged myocardin-related transcription factor import this mechanosensitive protein to the nucleus at higher rates and display faster motility. Locally unstructured regions lower the free-energy barrier of protein translocation and might offer a control mechanism for nuclear mechanotransduction.
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Affiliation(s)
- Fani Panagaki
- Single Molecule Mechanobiology Laboratory, The Francis Crick Institute, London, UK
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King’s College London, London, UK
| | - Rafael Tapia-Rojo
- Single Molecule Mechanobiology Laboratory, The Francis Crick Institute, London, UK
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King’s College London, London, UK
| | - Tong Zhu
- Single Molecule Mechanobiology Laboratory, The Francis Crick Institute, London, UK
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King’s College London, London, UK
| | - Natalie Milmoe
- Single Molecule Mechanobiology Laboratory, The Francis Crick Institute, London, UK
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King’s College London, London, UK
| | - Patricia Paracuellos
- Single Molecule Mechanobiology Laboratory, The Francis Crick Institute, London, UK
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King’s College London, London, UK
| | - Stephanie Board
- Single Molecule Mechanobiology Laboratory, The Francis Crick Institute, London, UK
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King’s College London, London, UK
| | - Marc Mora
- Single Molecule Mechanobiology Laboratory, The Francis Crick Institute, London, UK
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King’s College London, London, UK
| | - Jane Walker
- Single Molecule Mechanobiology Laboratory, The Francis Crick Institute, London, UK
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King’s College London, London, UK
| | - Elena Rostkova
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King’s College London, London, UK
| | - Andrew Stannard
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King’s College London, London, UK
| | - Elvira Infante
- Single Molecule Mechanobiology Laboratory, The Francis Crick Institute, London, UK
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King’s College London, London, UK
| | - Sergi Garcia-Manyes
- Single Molecule Mechanobiology Laboratory, The Francis Crick Institute, London, UK
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King’s College London, London, UK
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3
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Kasal MR, Kotamarthi HC, Johnson MM, Stephens HM, Lang MJ, Sauer RT, Baker TA. Lon degrades stable substrates slowly but with enhanced processivity, redefining the attributes of a successful AAA+ protease. Cell Rep 2023; 42:113061. [PMID: 37660294 PMCID: PMC10695633 DOI: 10.1016/j.celrep.2023.113061] [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: 03/02/2023] [Revised: 07/15/2023] [Accepted: 08/16/2023] [Indexed: 09/05/2023] Open
Abstract
Lon is a widely distributed AAA+ (ATPases associated with diverse cellular activities) protease known for degrading poorly folded and damaged proteins and is often classified as a weak protein unfoldase. Here, using a Lon-degron pair from Mesoplasma florum (MfLon and MfssrA, respectively), we perform ensemble and single-molecule experiments to elucidate the molecular mechanisms underpinning MfLon function. Notably, we find that MfLon unfolds and degrades stably folded substrates and that translocation of these unfolded polypeptides occurs with a ∼6-amino-acid step size. Moreover, the time required to hydrolyze one ATP corresponds to the dwell time between steps, indicating that one step occurs per ATP-hydrolysis-fueled "power stroke." Comparison of MfLon to related AAA+ enzymes now provides strong evidence that HCLR-clade enzymes function using a shared power-stroke mechanism and, surprisingly, that MfLon is more processive than ClpXP and ClpAP. We propose that ample unfoldase strength and substantial processivity are features that contribute to the Lon family's evolutionary success.
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Affiliation(s)
- Meghann R Kasal
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | | | - Madeline M Johnson
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - Hannah M Stephens
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - Matthew J Lang
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - Robert T Sauer
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Tania A Baker
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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4
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González-Paz L, Lossada C, Hurtado-León ML, Fernández-Materán FV, Paz JL, Parvizi S, Cardenas Castillo RE, Romero F, Alvarado YJ. Intrinsic Dynamics of the ClpXP Proteolytic Machine Using Elastic Network Models. ACS OMEGA 2023; 8:7302-7318. [PMID: 36873006 PMCID: PMC9979342 DOI: 10.1021/acsomega.2c04347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Accepted: 10/25/2022] [Indexed: 06/18/2023]
Abstract
ClpXP complex is an ATP-dependent mitochondrial matrix protease that binds, unfolds, translocates, and subsequently degrades specific protein substrates. Its mechanisms of operation are still being debated, and several have been proposed, including the sequential translocation of two residues (SC/2R), six residues (SC/6R), and even long-pass probabilistic models. Therefore, it has been suggested to employ biophysical-computational approaches that can determine the kinetics and thermodynamics of the translocation. In this sense, and based on the apparent inconsistency between structural and functional studies, we propose to apply biophysical approaches based on elastic network models (ENM) to study the intrinsic dynamics of the theoretically most probable hydrolysis mechanism. The proposed models ENM suggest that the ClpP region is decisive for the stabilization of the ClpXP complex, contributing to the flexibility of the residues adjacent to the pore, favoring the increase in pore size and, therefore, with the energy of interaction of its residues with a larger portion of the substrate. It is predicted that the complex may undergo a stable configurational change once assembled and that the deformability of the system once assembled is oriented, to increase the rigidity of the domains of each region (ClpP and ClpX) and to gain flexibility of the pore. Our predictions could suggest under the conditions of this study the mechanism of the interaction of the system, of which the substrate passes through the unfolding of the pore in parallel with a folding of the bottleneck. The variations in the distance calculated by molecular dynamics could allow the passage of a substrate with a size equivalent to ∼3 residues. The theoretical behavior of the pore and the stability and energy of binding to the substrate based on ENM models suggest that in this system, there are thermodynamic, structural, and configurational conditions that allow a possible translocation mechanism that is not strictly sequential.
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Affiliation(s)
- Lenin González-Paz
- Facultad
Experimental de Ciencias (FEC), Departamento de Biología, Laboratorio
de Genética y Biología Molecular (LGBM), Universidad del Zulia (LUZ), 4001 Maracaibo, Zulia, República Bolivariana
de Venezuela
- Centro
de Biomedicina Molecular (CBM). Laboratorio de Biocomputación
(LB), Instituto Venezolano de Investigaciones
Científicas (IVIC), 4001 Maracaibo, Zulia, República Bolivariana de Venezuela
| | - Carla Lossada
- Centro
de Biomedicina Molecular (CBM). Laboratorio de Biocomputación
(LB), Instituto Venezolano de Investigaciones
Científicas (IVIC), 4001 Maracaibo, Zulia, República Bolivariana de Venezuela
| | - Maria Laura Hurtado-León
- Facultad
Experimental de Ciencias (FEC), Departamento de Biología, Laboratorio
de Genética y Biología Molecular (LGBM), Universidad del Zulia (LUZ), 4001 Maracaibo, Zulia, República Bolivariana
de Venezuela
| | - Francelys V. Fernández-Materán
- Centro
de Biomedicina Molecular (CBM). Laboratorio de Biocomputación
(LB), Instituto Venezolano de Investigaciones
Científicas (IVIC), 4001 Maracaibo, Zulia, República Bolivariana de Venezuela
| | - José Luis Paz
- Departamento
Académico de Química Inorgánica, Facultad de
Química e Ingeniería Química, Universidad Nacional Mayor de San Marcos, 15081 Lima, Perú
| | - Shayan Parvizi
- Pulmonary,
Critical Care and Sleep Medicine, Baylor
College of Medicine, Houston, Texas 77030, United States
| | | | - Freddy Romero
- Pulmonary,
Critical Care and Sleep Medicine, Baylor
College of Medicine, Houston, Texas 77030, United States
| | - Ysaias J. Alvarado
- Centro
de Biomedicina Molecular (CBM), Laboratorio de Química Biofísica
Teórica y Experimental (LQBTE), Instituto
Venezolano de Investigaciones Cientificas (IVIC), 4001 Maracaibo, Zulia, República Bolivariana de Venezuela
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5
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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: 2.0] [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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6
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Beedle AEM, Garcia-Manyes S. The role of single protein elasticity in mechanobiology. NATURE REVIEWS. MATERIALS 2023; 8:10-24. [PMID: 37469679 PMCID: PMC7614781 DOI: 10.1038/s41578-022-00488-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 09/07/2022] [Indexed: 07/21/2023]
Abstract
In addition to biochemical signals and genetic considerations, mechanical forces are rapidly emerging as a master regulator of human physiology. Yet the molecular mechanisms that regulate force-induced functionalities across a wide range of scales, encompassing the cell, tissue or organ levels, are comparatively not so well understood. With the advent, development and refining of single molecule nanomechanical techniques, enabling to exquisitely probe the conformational dynamics of individual proteins under the effect of a calibrated force, we have begun to acquire a comprehensive knowledge on the rich plethora of physicochemical principles that regulate the elasticity of single proteins. Here we review the major advances underpinning our current understanding of how the elasticity of single proteins regulates mechanosensing and mechanotransduction. We discuss the present limitations and future challenges of such a prolific and burgeoning field.
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Affiliation(s)
- Amy EM Beedle
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King’s College London, Strand, WC2R 2LS London, United Kingdom
- Institute for Bioengineering of Catalonia (IBEC), the Barcelona Institute of Technology (BIST), 08028 Barcelona, Spain
| | - Sergi Garcia-Manyes
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King’s College London, Strand, WC2R 2LS London, United Kingdom
- Single Molecule Mechanobiology Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, London, UK
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7
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Jonsson E, Htet ZM, Bard JA, Dong KC, Martin A. Ubiquitin modulates 26 S proteasome conformational dynamics and promotes substrate degradation. SCIENCE ADVANCES 2022; 8:eadd9520. [PMID: 36563145 PMCID: PMC9788759 DOI: 10.1126/sciadv.add9520] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 10/27/2022] [Indexed: 06/17/2023]
Abstract
The 26S proteasome recognizes thousands of appropriate protein substrates in eukaryotic cells through attached ubiquitin chains and uses its adenosine triphosphatase (ATPase) motor for mechanical unfolding and translocation into a proteolytic chamber. Here, we used single-molecule Förster resonance energy transfer measurements to monitor the conformational dynamics of the proteasome, observe individual substrates during their progression toward degradation, and elucidate how these processes are regulated by ubiquitin chains. Rapid transitions between engagement- and processing-competent proteasome conformations control substrate access to the ATPase motor. Ubiquitin chain binding functions as an allosteric regulator to slow these transitions, stabilize the engagement-competent state, and aid substrate capture to accelerate degradation initiation. Upon substrate engagement, the proteasome remains in processing-competent states for translocation and unfolding, except for apparent motor slips when encountering stably folded domains. Our studies revealed how ubiquitin chains allosterically regulate degradation initiation, which ensures substrate selectivity in a crowded cellular environment.
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Affiliation(s)
- Erik Jonsson
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA
- California Institute for Quantitative Biosciences, University of California at Berkeley, Berkeley, CA 94720, USA
- Howard Hughes Medical Institute, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Zaw Min Htet
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA
- California Institute for Quantitative Biosciences, University of California at Berkeley, Berkeley, CA 94720, USA
- Howard Hughes Medical Institute, University of California at Berkeley, Berkeley, CA 94720, USA
| | | | - Ken C. Dong
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA
- California Institute for Quantitative Biosciences, University of California at Berkeley, Berkeley, CA 94720, USA
- Howard Hughes Medical Institute, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Andreas Martin
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA
- California Institute for Quantitative Biosciences, University of California at Berkeley, Berkeley, CA 94720, USA
- Howard Hughes Medical Institute, University of California at Berkeley, Berkeley, CA 94720, USA
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8
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Walker SD, Olivares AO. The activated ClpP peptidase forcefully grips a protein substrate. Biophys J 2022; 121:3907-3916. [PMID: 36045571 PMCID: PMC9674977 DOI: 10.1016/j.bpj.2022.08.042] [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: 04/29/2022] [Revised: 08/12/2022] [Accepted: 08/26/2022] [Indexed: 11/26/2022] Open
Abstract
ATPases associated with diverse cellular activities (AAA+) proteases power the maintenance of protein homeostasis by coupling ATP hydrolysis to mechanical protein unfolding, translocation, and ultimately degradation. Although ATPase activity drives a large portion of the mechanical work these molecular machines perform, how the peptidase contributes to the forceful denaturation and processive threading of substrates remains unknown. Here, using single-molecule optical trapping, we examine the mechanical activity of the caseinolytic peptidase P (ClpP) from Escherichia coli in the absence of a partner ATPase and in the presence of an activating small-molecule acyldepsipeptide. We demonstrate that ClpP grips protein substrate under mechanical loads exceeding 40 pN, which are greater than those observed for the AAA+ unfoldase ClpX and the AAA+ protease complexes ClpXP and ClpAP. We further characterize substrate-ClpP bond lifetimes and rupture forces under varying loads. We find that the resulting slip bond behavior does not depend on ClpP peptidase activity. In addition, we find that unloaded bond lifetimes between ClpP and protein substrate are on a timescale relevant to unfolding times (up to ∼160 s) for difficult to unfold model substrate proteins. These direct measurements of the substrate-peptidase bond under load define key properties required by AAA+ proteases to mechanically unfold and degrade protein substrates.
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Affiliation(s)
- Steven D Walker
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee; Chemical and Physical Biology Graduate Program, Vanderbilt University, Nashville, Tennessee
| | - Adrian O Olivares
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee.
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9
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Wang X, Simon SM, Coffino P. Single molecule microscopy reveals diverse actions of substrate sequences that impair ClpX AAA+ ATPase function. J Biol Chem 2022; 298:102457. [PMID: 36064000 PMCID: PMC9531181 DOI: 10.1016/j.jbc.2022.102457] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 08/25/2022] [Accepted: 08/26/2022] [Indexed: 10/28/2022] Open
Abstract
AAA+ (ATPases Associated with diverse cellular Activities) proteases unfold substrate proteins by pulling the substrate polypeptide through a narrow pore. To overcome the barrier to unfolding, substrates may require extended association with the ATPase. Failed unfolding attempts can lead to a slip of grip, which may result in substrate dissociation, but how substrate sequence affects slippage is unresolved. Here, we measured single molecule dwell time using total internal reflection fluorescence microscopy, scoring time-dependent dissociation of engaged substrates from bacterial AAA+ ATPase unfoldase/translocase ClpX. Substrates comprising a stable domain resistant to unfolding and a C-terminal unstructured tail, tagged with a degron for initiating translocase insertion, were used to determine dwell time in relation to tail length and composition. We found greater tail length promoted substrate retention during futile unfolding. Additionally, we tested two tail compositions known to frustrate unfolding. A poly-glycine tract (polyG) promoted release, but only when adjacent to the folded domain, whereas glycine-alanine repeats (GAr) did not promote release. A high complexity motif containing polar and charged residues also promoted release. We further investigated the impact of these and related motifs on substrate degradation rates and ATP consumption, using the unfoldase-protease complex ClpXP. Here, substrate domain stability modulates the effects of substrate tail sequences. polyG and GAr are both inhibitory for unfolding, but act in different ways. GAr motifs only negatively affected degradation of highly stable substrates, which is accompanied by reduced ClpXP ATPase activity. Together, our results specify substrate characteristics that affect unfolding and degradation by ClpXP.
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Affiliation(s)
- Xiao Wang
- Laboratory of Cellular Biophysics, The Rockefeller University, New York, New York, USA
| | - Sanford M Simon
- Laboratory of Cellular Biophysics, The Rockefeller University, New York, New York, USA
| | - Philip Coffino
- Laboratory of Cellular Biophysics, The Rockefeller University, New York, New York, USA.
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10
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Morehouse JP, Baker TA, Sauer RT. FtsH degrades dihydrofolate reductase by recognizing a partially folded species. Protein Sci 2022; 31:e4410. [PMID: 36630366 PMCID: PMC9601784 DOI: 10.1002/pro.4410] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 07/21/2022] [Accepted: 07/24/2022] [Indexed: 01/14/2023]
Abstract
AAA+ proteolytic machines play essential roles in maintaining and rebalancing the cellular proteome in response to stress, developmental cues, and environmental changes. Of the five AAA+ proteases in Escherichia coli, FtsH is unique in its attachment to the inner membrane and its function in degrading both membrane and cytosolic proteins. E. coli dihydrofolate reductase (DHFR) is a stable and biophysically well-characterized protein, which a previous study found resisted FtsH degradation despite the presence of an ssrA degron. By contrast, we find that FtsH degrades DHFR fused to a long peptide linker and ssrA tag. Surprisingly, we also find that FtsH degrades DHFR with shorter linkers and ssrA tag, and without any linker or tag. Thus, FtsH must be able to recognize a sequence element or elements within DHFR. We find that FtsH degradation of DHFR is noncanonical in the sense that it does not rely upon recognition of an unstructured polypeptide at or near the N-terminus or C-terminus of the substrate. Results using peptide-array experiments, mutant DHFR proteins, and fusion proteins suggest that FtsH recognizes an internal sequence in a species of DHFR that is partially unfolded. Overall, our findings provide insight into substrate recognition by FtsH and indicate that its degradation capacity is broader than previously reported.
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Affiliation(s)
- Juhee P. Morehouse
- Department of BiologyMassachusetts Institute of TechnologyCambridgeMassachusettsUSA
| | - Tania A. Baker
- Department of BiologyMassachusetts Institute of TechnologyCambridgeMassachusettsUSA
| | - Robert T. Sauer
- Department of BiologyMassachusetts Institute of TechnologyCambridgeMassachusettsUSA
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11
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Andreu I, Granero-Moya I, Garcia-Manyes S, Roca-Cusachs P. Understanding the role of mechanics in nucleocytoplasmic transport. APL Bioeng 2022; 6:020901. [PMID: 35783457 PMCID: PMC9246425 DOI: 10.1063/5.0076034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 02/03/2022] [Indexed: 01/26/2023] Open
Abstract
Cell nuclei are submitted to mechanical forces, which in turn affect nuclear and cell functions. Recent evidence shows that a crucial mechanically regulated nuclear function is nucleocytoplasmic transport, mediated by nuclear pore complexes (NPCs). Mechanical regulation occurs at two levels: first, by force application to the nucleus, which increases NPC permeability likely through NPC stretch. Second, by the mechanical properties of the transported proteins themselves, as mechanically labile proteins translocate through NPCs faster than mechanically stiff ones. In this perspective, we discuss this evidence and the associated mechanisms by which mechanics can regulate the nucleo-cytoplasmic partitioning of proteins. Finally, we analyze how mechanical regulation of nucleocytoplasmic transport can provide a systematic approach to the study of mechanobiology and open new avenues both in fundamental and applied research.
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Affiliation(s)
- Ion Andreu
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Technology (BIST), 08028 Barcelona, Spain
| | | | - Sergi Garcia-Manyes
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, King's College London, WC2R 2LS London, United Kingdom; Single Molecule Mechanobiology Laboratory, The Francis Crick Institute, NW1 1AT London, United Kingdom
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12
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Abstract
The p97 AAA+ATPase is an essential and abundant regulator of protein homeostasis that plays a central role in unfolding ubiquitylated substrates. Here we report two cryo-EM structures of human p97 in complex with its p47 adaptor. One of the conformations is six-fold symmetric, corresponds to previously reported structures of p97, and lacks bound substrate. The other structure adopts a helical conformation, displays substrate running in an extended conformation through the pore of the p97 hexamer, and resembles structures reported for other AAA unfoldases. These findings support the model that p97 utilizes a "hand-over-hand" mechanism in which two residues of the substrate are translocated for hydrolysis of two ATPs, one in each of the two p97 AAA ATPase rings. Proteomics analysis supports the model that one p97 complex can bind multiple substrate adaptors or binding partners, and can process substrates with multiple types of ubiquitin modification.
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13
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Sauer RT, Fei X, Bell TA, Baker TA. Structure and function of ClpXP, a AAA+ proteolytic machine powered by probabilistic ATP hydrolysis. Crit Rev Biochem Mol Biol 2022; 57:188-204. [PMID: 34923891 PMCID: PMC9871882 DOI: 10.1080/10409238.2021.1979461] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
ClpXP is an archetypical AAA+ protease, consisting of ClpX and ClpP. ClpX is an ATP-dependent protein unfoldase and polypeptide translocase, whereas ClpP is a self-compartmentalized peptidase. ClpXP is currently the only AAA+ protease for which high-resolution structures exist, the molecular basis of recognition for a protein substrate is understood, extensive biochemical and genetic analysis have been performed, and single-molecule optical trapping has allowed direct visualization of the kinetics of substrate unfolding and translocation. In this review, we discuss our current understanding of ClpXP structure and function, evaluate competing sequential and probabilistic mechanisms of ATP hydrolysis, and highlight open questions for future exploration.
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Affiliation(s)
- Robert T. Sauer
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Xue Fei
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Tristan A. Bell
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Tania A. Baker
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
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14
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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: 25] [Impact Index Per Article: 12.5] [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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15
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Khan YA, White KI, Brunger AT. The AAA+ superfamily: a review of the structural and mechanistic principles of these molecular machines. Crit Rev Biochem Mol Biol 2021; 57:156-187. [PMID: 34632886 DOI: 10.1080/10409238.2021.1979460] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
ATPases associated with diverse cellular activities (AAA+ proteins) are a superfamily of proteins found throughout all domains of life. The hallmark of this family is a conserved AAA+ domain responsible for a diverse range of cellular activities. Typically, AAA+ proteins transduce chemical energy from the hydrolysis of ATP into mechanical energy through conformational change, which can drive a variety of biological processes. AAA+ proteins operate in a variety of cellular contexts with diverse functions including disassembly of SNARE proteins, protein quality control, DNA replication, ribosome assembly, and viral replication. This breadth of function illustrates both the importance of AAA+ proteins in health and disease and emphasizes the importance of understanding conserved mechanisms of chemo-mechanical energy transduction. This review is divided into three major portions. First, the core AAA+ fold is presented. Next, the seven different clades of AAA+ proteins and structural details and reclassification pertaining to proteins in each clade are described. Finally, two well-known AAA+ proteins, NSF and its close relative p97, are reviewed in detail.
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Affiliation(s)
- Yousuf A Khan
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA.,Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA.,Department of Structural Biology, Stanford University, Stanford, CA, USA.,Department of Photon Science, Stanford University, Stanford, CA, USA.,Center for Biomedical Informatics Research, Stanford University, Stanford, CA, USA
| | - K Ian White
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA.,Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA.,Department of Structural Biology, Stanford University, Stanford, CA, USA.,Department of Photon Science, Stanford University, Stanford, CA, USA.,Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Axel T Brunger
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA.,Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA.,Department of Structural Biology, Stanford University, Stanford, CA, USA.,Department of Photon Science, Stanford University, Stanford, CA, USA.,Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
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16
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Harwood CR, Kikuchi Y. The ins and outs of Bacillus proteases: activities, functions and commercial significance. FEMS Microbiol Rev 2021; 46:6354784. [PMID: 34410368 PMCID: PMC8767453 DOI: 10.1093/femsre/fuab046] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 08/17/2021] [Indexed: 12/23/2022] Open
Abstract
Because the majority of bacterial species divide by binary fission, and do not have distinguishable somatic and germline cells, they could be considered to be immortal. However, bacteria ‘age’ due to damage to vital cell components such as DNA and proteins. DNA damage can often be repaired using efficient DNA repair mechanisms. However, many proteins have a functional ‘shelf life’; some are short lived, while others are relatively stable. Specific degradation processes are built into the life span of proteins whose activities are required to fulfil a specific function during a prescribed period of time (e.g. cell cycle, differentiation process, stress response). In addition, proteins that are irreparably damaged or that have come to the end of their functional life span need to be removed by quality control proteases. Other proteases are involved in performing a variety of specific functions that can be broadly divided into three categories: processing, regulation and feeding. This review presents a systematic account of the proteases of Bacillus subtilis and their activities. It reviews the proteases found in, or associated with, the cytoplasm, the cell membrane, the cell wall and the external milieu. Where known, the impacts of the deletion of particular proteases are discussed, particularly in relation to industrial applications.
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Affiliation(s)
- Colin R Harwood
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University NE2 4AX, Newcastle upon Tyne, UK
| | - Yoshimi Kikuchi
- Research Institute for Bioscience Products & Fine Chemicals, Ajinomoto Co., Inc., Kawasaki 210-8681, JAPAN
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17
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Jones EC, Uphoff S. Single-molecule imaging of LexA degradation in Escherichia coli elucidates regulatory mechanisms and heterogeneity of the SOS response. Nat Microbiol 2021; 6:981-990. [PMID: 34183814 PMCID: PMC7611437 DOI: 10.1038/s41564-021-00930-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 05/27/2021] [Indexed: 12/20/2022]
Abstract
The bacterial SOS response stands as a paradigm of gene networks controlled by a master transcriptional regulator. Self-cleavage of the SOS repressor, LexA, induces a wide range of cell functions that are critical for survival and adaptation when bacteria experience stress conditions1, including DNA repair2, mutagenesis3,4, horizontal gene transfer5–7, filamentous growth, and the induction of bacterial toxins8–12, toxin-antitoxin systems13, virulence factors6,14, and prophages15–17. SOS induction is also implicated in biofilm formation and antibiotic persistence11,18–20. Considering the fitness burden of these functions, it is surprising that the expression of LexA-regulated genes is highly variable across cells10,21–23 and that cell subpopulations induce the SOS response spontaneously even in the absence of stress exposure9,11,12,16,24,25. Whether this reflects a population survival strategy or a regulatory inaccuracy is unclear, as are the mechanisms underlying SOS heterogeneity. Here, we developed a single-molecule imaging approach based on a HaloTag fusion to directly monitor LexA inside live Escherichia coli cells, demonstrating the existence of 3 main states of LexA: DNA-bound stationary molecules, free LexA and degraded LexA species. These analyses elucidate the mechanisms by which DNA-binding and degradation of LexA regulate the SOS response in vivo. We show that self-cleavage of LexA occurs frequently throughout the population during unperturbed growth, rather than being restricted to a subpopulation of cells, which causes substantial cell-to-cell variation in LexA abundances. LexA variability underlies SOS gene expression heterogeneity and triggers spontaneous SOS pulses, which enhance bacterial survival in anticipation of stress.
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Affiliation(s)
- Emma C Jones
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Stephan Uphoff
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom.
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18
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Abstract
Multiple gram-negative bacteria encode type III secretion systems (T3SS) that allow them to inject effector proteins directly into host cells to facilitate colonization. To be secreted, effector proteins must be at least partially unfolded to pass through the narrow needle-like channel (diameter <2 nm) of the T3SS. Fusion of effector proteins to tightly packed proteins-such as GFP, ubiquitin, or dihydrofolate reductase (DHFR)-impairs secretion and results in obstruction of the T3SS. Prior observation that unfolding can become rate-limiting for secretion has led to the model that T3SS effector proteins have low thermodynamic stability, facilitating their secretion. Here, we first show that the unfolding free energy ([Formula: see text]) of two Salmonella effector proteins, SptP and SopE2, are 6.9 and 6.0 kcal/mol, respectively, typical for globular proteins and similar to published [Formula: see text] for GFP, ubiquitin, and DHFR. Next, we mechanically unfolded individual SptP and SopE2 molecules by atomic force microscopy (AFM)-based force spectroscopy. SptP and SopE2 unfolded at low force (F unfold ≤ 17 pN at 100 nm/s), making them among the most mechanically labile proteins studied to date by AFM. Moreover, their mechanical compliance is large, as measured by the distance to the transition state (Δx ‡ = 1.6 and 1.5 nm for SptP and SopE2, respectively). In contrast, prior measurements of GFP, ubiquitin, and DHFR show them to be mechanically robust (F unfold > 80 pN) and brittle (Δx ‡ < 0.4 nm). These results suggest that effector protein unfolding by T3SS is a mechanical process and that mechanical lability facilitates efficient effector protein secretion.
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19
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Kotamarthi HC, Sauer RT, Baker TA. The Non-dominant AAA+ Ring in the ClpAP Protease Functions as an Anti-stalling Motor to Accelerate Protein Unfolding and Translocation. Cell Rep 2021; 30:2644-2654.e3. [PMID: 32101742 DOI: 10.1016/j.celrep.2020.01.110] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 11/25/2019] [Accepted: 01/30/2020] [Indexed: 10/24/2022] Open
Abstract
ATP-powered unfoldases containing D1 and D2 AAA+ rings play important roles in protein homeostasis, but uncertainty about the function of each ring remains. Here we use single-molecule optical tweezers to assay mechanical unfolding and translocation by a variant of the ClpAP protease containing an ATPase-inactive D1 ring. This variant displays substantial mechanical defects in both unfolding and translocation of protein substrates. Notably, when D1 is hydrolytically inactive, ClpAP often stalls for times as long as minutes, and the substrate can back-slip through the enzyme when ATP concentrations are low. The inactive D1 variant also has more difficulty traveling in the N-to-C direction on a polypeptide track than it does moving in a C-to-N direction. These results indicate that D1 normally functions as an auxiliary/regulatory motor to promote uninterrupted enzyme advancement that is fueled largely by the D2 ring.
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Affiliation(s)
- Hema Chandra Kotamarthi
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA; Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Robert T Sauer
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | - Tania A Baker
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA; Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA, USA.
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20
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Kang ZH, Liu YT, Gou Y, Deng QR, Hu ZY, Li GR. Progress and prospect of single-molecular ClpX ATPase researching system-a mini-review. Gene 2021; 774:145420. [PMID: 33434627 DOI: 10.1016/j.gene.2021.145420] [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: 10/08/2020] [Revised: 12/04/2020] [Accepted: 01/05/2021] [Indexed: 11/28/2022]
Abstract
ClpXP in Escherichia coli is a proteasome degrading protein substrates. It consists of one hexamer of ATPase (ClpX) and two heptamers of peptidase (ClpP). The ClpX binds ATP and translocates the substrate protein into the ClpP chamber by binding and hydrolysis of ATP. At single molecular level, ClpX harnesses cycles of power stroke (dwell and burst) to unfold the substrates, then releases the ADP and Pi. Based on the construction and function of ClpXP, especially the recent progress on how ClpX unfold protein substrates, in this mini-review, a currently proposed single ClpX molecular model system detected by optical tweezers, and its prospective for the elucidation of the mechanism of force generation of ClpX in its power stroke and the subunit interaction with each other, were discussed in detail.
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Affiliation(s)
- Zhen-Hui Kang
- School of Bioengineering, Sichuan University of Science & Engineering, Yibin 644005, Sichuan, China.
| | - Yi-Ting Liu
- School of Bioengineering, Sichuan University of Science & Engineering, Yibin 644005, Sichuan, China
| | - Yang Gou
- School of Bioengineering, Sichuan University of Science & Engineering, Yibin 644005, Sichuan, China
| | - Qi-Rui Deng
- School of Bioengineering, Sichuan University of Science & Engineering, Yibin 644005, Sichuan, China
| | - Zi-Yu Hu
- School of Bioengineering, Sichuan University of Science & Engineering, Yibin 644005, Sichuan, China
| | - Guan-Rong Li
- Southwest University, Beibei 400716, Chongqing, China.
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21
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Multistep substrate binding and engagement by the AAA+ ClpXP protease. Proc Natl Acad Sci U S A 2020; 117:28005-28013. [PMID: 33106413 DOI: 10.1073/pnas.2010804117] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Escherichia coli ClpXP is one of the most thoroughly studied AAA+ proteases, but relatively little is known about the reactions that allow it to bind and then engage specific protein substrates before the adenosine triphosphate (ATP)-fueled mechanical unfolding and translocation steps that lead to processive degradation. Here, we employ a fluorescence-quenching assay to study the binding of ssrA-tagged substrates to ClpXP. Polyphasic stopped-flow association and dissociation kinetics support the existence of at least three distinct substrate-bound complexes. These kinetic data fit well to a model in which ClpXP and substrate form an initial recognition complex followed by an intermediate complex and then, an engaged complex that is competent for substrate unfolding. The initial association and dissociation steps do not require ATP hydrolysis, but subsequent forward and reverse kinetic steps are accelerated by faster ATP hydrolysis. Our results, together with recent cryo-EM structures of ClpXP bound to substrates, support a model in which the ssrA degron initially binds in the top portion of the axial channel of the ClpX hexamer and then is translocated deeper into the channel in steps that eventually pull the native portion of the substrate against the channel opening. Reversible initial substrate binding allows ClpXP to check potential substrates for degrons, potentially increasing specificity. Subsequent substrate engagement steps allow ClpXP to grip a wide variety of sequences to ensure efficient unfolding and translocation of almost any native substrate.
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22
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Modular and coordinated activity of AAA+ active sites in the double-ring ClpA unfoldase of the ClpAP protease. Proc Natl Acad Sci U S A 2020; 117:25455-25463. [PMID: 33020301 PMCID: PMC7568338 DOI: 10.1073/pnas.2014407117] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Understanding of how ClpA and other double-ring AAA+ enzymes perform mechanical work is limited. Using site-specific cross-linking and mutagenesis, we introduced ATPase-inactive AAA+ modules at alternating positions in individual ClpA rings, or in both rings, to investigate potential active-site coordination during ClpAP degradation. ClpA variants containing alternating active/inactive ATPase modules processively unfolded, translocated, and supported ClpP degradation of protein substrates with energetic efficiencies similar to, or higher than, completely active ClpA. These results impact current models describing the mechanisms of AAA+ family enzymes. The cross-linking/mutagenesis method we employed will also be useful for answering other structure-function questions about ClpA and related double-ring enzymes. ClpA is a hexameric double-ring AAA+ unfoldase/translocase that functions with the ClpP peptidase to degrade proteins that are damaged or unneeded. How the 12 ATPase active sites of ClpA, 6 in the D1 ring and 6 in the D2 ring, work together to fuel ATP-dependent degradation is not understood. We use site-specific cross-linking to engineer ClpA hexamers with alternating ATPase-active and ATPase-inactive modules in the D1 ring, the D2 ring, or both rings to determine if these active sites function together. Our results demonstrate that D2 modules coordinate with D1 modules and ClpP during mechanical work. However, there is no requirement for adjacent modules in either ring to be active for efficient enzyme function. Notably, ClpAP variants with just three alternating active D2 modules are robust protein translocases and function with double the energetic efficiency of ClpAP variants with completely active D2 rings. Although D2 is the more powerful motor, three or six active D1 modules are important for high enzyme processivity, which depends on D1 and D2 acting coordinately. These results challenge sequential models of ATP hydrolysis and coupled mechanical work by ClpAP and provide an engineering strategy that will be useful in testing other aspects of ClpAP mechanism.
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23
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Avestan MS, Javidi A, Ganote LP, Brown JM, Stan G. Kinetic effects in directional proteasomal degradation of the green fluorescent protein. J Chem Phys 2020; 153:105101. [DOI: 10.1063/5.0015191] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Affiliation(s)
| | - Alex Javidi
- Data Sciences, Janssen Research and Development, Spring House, Pennsylvania 19477, USA
| | | | | | - George Stan
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, USA
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24
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Wu S, Guo Y, Joan HI, Tu Y, Adil MF, Sehar S, Zhao D, Shamsi IH. iTRAQ-based comparative proteomic analysis reveals high temperature accelerated leaf senescence of tobacco (Nicotiana tabacum L.) during flue-curing. Genomics 2020; 112:3075-3088. [PMID: 32454168 DOI: 10.1016/j.ygeno.2020.05.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 05/17/2020] [Accepted: 05/20/2020] [Indexed: 11/25/2022]
Abstract
Tobacco (Nicotiana tabacum) is extensively cultivated all over the world for its economic value. During curing and storage, senescence occurs, which is associated with physiological and biochemical changes in postharvest plant organs. However, the molecular mechanisms involved in accelerated senescence due to high temperatures in tobacco leaves during curing need further elaboration. We studied molecular mechanisms of senescence in tobacco leaves exposed to high temperature during curing (Fresh, 38 °C and 42 °C), revealed by isobaric tags for relative and absolute quantification (iTRAQ) for the proteomic profiles of cultivar Bi'na1. In total, 8903 proteins were identified, and 2034 (1150 up-regulated and 1074 down-regulated) differentially abundant proteins (DAPs) were obtained from tobacco leaf samples. These DAPs were mainly involved in posttranslational modification, protein turnover, energy production and conversion. Sugar- and energy-related metabolic biological processes and pathways might be critical regulators of tobacco leaves exposed to high temperature during senescence. High-temperature stress accelerated tobacco leaf senescence mainly by down-regulating photosynthesis-related pathways and degrading cellular constituents to maintain cell viability and nutrient recycling. Our findings provide a valuable inventory of novel proteins involved in senescence physiology and elucidate the protein regulatory network in postharvest organs exposed to high temperatures during flue-curing.
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Affiliation(s)
- Shengjiang Wu
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, The Key Laboratory of Plant Resources Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), Guizhou University, Guiyang 550025, PR China; Guizhou Academy of Tobacco Science, Key Laboratory of Molecular Genetics/Upland Flue-cured Tobacco Quality and Ecology Key Laboratory, CNTC, Guiyang 550081, PR China
| | - Yushuang Guo
- Guizhou Academy of Tobacco Science, Key Laboratory of Molecular Genetics/Upland Flue-cured Tobacco Quality and Ecology Key Laboratory, CNTC, Guiyang 550081, PR China
| | - Heren Issaka Joan
- Department of Agronomy, College of Agriculture and Biotechnology, Key Laboratory of Crop Germplasm Resource, Zhejiang University, Hangzhou 310058, PR China
| | - Yonggao Tu
- Guizhou Academy of Tobacco Science, Key Laboratory of Molecular Genetics/Upland Flue-cured Tobacco Quality and Ecology Key Laboratory, CNTC, Guiyang 550081, PR China
| | - Muhammad Faheem Adil
- Department of Agronomy, College of Agriculture and Biotechnology, Key Laboratory of Crop Germplasm Resource, Zhejiang University, Hangzhou 310058, PR China
| | - Shafaque Sehar
- Department of Agronomy, College of Agriculture and Biotechnology, Key Laboratory of Crop Germplasm Resource, Zhejiang University, Hangzhou 310058, PR China
| | - Degang Zhao
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, The Key Laboratory of Plant Resources Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), Guizhou University, Guiyang 550025, PR China; Guizhou Academy of Agricultural Sciences, Guiyang 550006, PR China.
| | - Imran Haider Shamsi
- Department of Agronomy, College of Agriculture and Biotechnology, Key Laboratory of Crop Germplasm Resource, Zhejiang University, Hangzhou 310058, PR China.
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25
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Lopez KE, Rizo AN, Tse E, Lin J, Scull NW, Thwin AC, Lucius AL, Shorter J, Southworth DR. Conformational plasticity of the ClpAP AAA+ protease couples protein unfolding and proteolysis. Nat Struct Mol Biol 2020; 27:406-416. [PMID: 32313240 PMCID: PMC7529148 DOI: 10.1038/s41594-020-0409-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 03/09/2020] [Indexed: 11/09/2022]
Abstract
The ClpAP complex is a conserved bacterial protease that unfolds and degrades proteins targeted for destruction. The ClpA double-ring hexamer powers substrate unfolding and translocation into the ClpP proteolytic chamber. Here, we determined high-resolution structures of wild-type Escherichia coli ClpAP undergoing active substrate unfolding and proteolysis. A spiral of pore loop-substrate contacts spans both ClpA AAA+ domains. Protomers at the spiral seam undergo nucleotide-specific rearrangements, supporting substrate translocation. IGL loops extend flexibly to bind the planar, heptameric ClpP surface with the empty, symmetry-mismatched IGL pocket maintained at the seam. Three different structures identify a binding-pocket switch by the IGL loop of the lowest positioned protomer, involving release and re-engagement with the clockwise pocket. This switch is coupled to a ClpA rotation and a network of conformational changes across the seam, suggesting that ClpA can rotate around the ClpP apical surface during processive steps of translocation and proteolysis.
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Affiliation(s)
- Kyle E Lopez
- Graduate Program in Biophysics, University of California, San Francisco, San Francisco, CA, USA
- Department of Biochemistry and Biophysics, Institute for Neurodegenerative Diseases, University of California, San Francisco, San Francisco, CA, USA
| | - Alexandrea N Rizo
- Department of Biochemistry and Biophysics, Institute for Neurodegenerative Diseases, University of California, San Francisco, San Francisco, CA, USA
- Graduate Program in Chemical Biology, University of Michigan, Ann Arbor, MI, USA
| | - Eric Tse
- Department of Biochemistry and Biophysics, Institute for Neurodegenerative Diseases, University of California, San Francisco, San Francisco, CA, USA
| | - JiaBei Lin
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Nathaniel W Scull
- Department of Chemistry, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Aye C Thwin
- Department of Biochemistry and Biophysics, Institute for Neurodegenerative Diseases, University of California, San Francisco, San Francisco, CA, USA
| | - Aaron L Lucius
- Department of Chemistry, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - James Shorter
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Daniel R Southworth
- Department of Biochemistry and Biophysics, Institute for Neurodegenerative Diseases, University of California, San Francisco, San Francisco, CA, USA.
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26
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Fei X, Bell TA, Jenni S, Stinson BM, Baker TA, Harrison SC, Sauer RT. Structures of the ATP-fueled ClpXP proteolytic machine bound to protein substrate. eLife 2020; 9:52774. [PMID: 32108573 PMCID: PMC7112951 DOI: 10.7554/elife.52774] [Citation(s) in RCA: 84] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 02/27/2020] [Indexed: 01/11/2023] Open
Abstract
ClpXP is an ATP-dependent protease in which the ClpX AAA+ motor binds, unfolds, and translocates specific protein substrates into the degradation chamber of ClpP. We present cryo-EM studies of the E. coli enzyme that show how asymmetric hexameric rings of ClpX bind symmetric heptameric rings of ClpP and interact with protein substrates. Subunits in the ClpX hexamer assume a spiral conformation and interact with two-residue segments of substrate in the axial channel, as observed for other AAA+ proteases and protein-remodeling machines. Strictly sequential models of ATP hydrolysis and a power stroke that moves two residues of the substrate per translocation step have been inferred from these structural features for other AAA+ unfoldases, but biochemical and single-molecule biophysical studies indicate that ClpXP operates by a probabilistic mechanism in which five to eight residues are translocated for each ATP hydrolyzed. We propose structure-based models that could account for the functional results.
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Affiliation(s)
- Xue Fei
- Department of Biology, Massachusetts Institute of Technology, Cambridge, United States
| | - Tristan A Bell
- Department of Biology, Massachusetts Institute of Technology, Cambridge, United States
| | - Simon Jenni
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, United States
| | - Benjamin M Stinson
- Department of Biology, Massachusetts Institute of Technology, Cambridge, United States
| | - Tania A Baker
- Department of Biology, Massachusetts Institute of Technology, Cambridge, United States.,Howard Hughes Medical Institute, Chevy Chase, United States
| | - Stephen C Harrison
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, United States.,Howard Hughes Medical Institute, Chevy Chase, United States
| | - Robert T Sauer
- Department of Biology, Massachusetts Institute of Technology, Cambridge, United States
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27
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Basu S, Bahadur RP. Do sequence neighbours of intrinsically disordered regions promote structural flexibility in intrinsically disordered proteins? J Struct Biol 2020; 209:107428. [DOI: 10.1016/j.jsb.2019.107428] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 11/14/2019] [Accepted: 11/17/2019] [Indexed: 10/25/2022]
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28
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Liu Y, Chen J, Khusnutdinova AN, Correia K, Diep P, Batyrova KA, Nemr K, Flick R, Stogios P, Yakunin AF, Mahadevan R. A novel C-terminal degron identified in bacterial aldehyde decarbonylases using directed evolution. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:114. [PMID: 32612677 PMCID: PMC7325246 DOI: 10.1186/s13068-020-01753-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 06/16/2020] [Indexed: 05/10/2023]
Abstract
BACKGROUND Aldehyde decarbonylases (ADs), which convert acyl aldehydes into alkanes, supply promising solution for producing alkanes from renewable feedstock. However the instability of ADs impedes their further application. Therefore, the current study aimed to investigate the degradation mechanism of ADs and engineer it towards high stability. RESULTS Here, we describe the discovery of a degradation tag (degron) in the AD from marine cyanobacterium Prochlorococcus marinus using error-prone PCR-based directed evolution system. Bioinformatic analysis revealed that this C-terminal degron is common in bacterial ADs and identified a conserved C-terminal motif, RMSAYGLAAA, representing the AD degron (ADcon). Furthermore, we demonstrated that the ATP-dependent proteases ClpAP and Lon are involved in the degradation of AD-tagged proteins in E. coli, thereby limiting alkane production. Deletion or modification of the degron motif increased alkane production in vivo. CONCLUSION This work revealed the presence of a novel degron in bacterial ADs responsible for its instability. The in vivo experiments proved eliminating or modifying the degron could stabilize AD, thereby producing higher titers of alkanes.
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Affiliation(s)
- Yilan Liu
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON M5S 3E5 Canada
| | - Jinjin Chen
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON M5S 3E5 Canada
| | - Anna N. Khusnutdinova
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON M5S 3E5 Canada
| | - Kevin Correia
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON M5S 3E5 Canada
| | - Patrick Diep
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON M5S 3E5 Canada
| | - Khorcheska A. Batyrova
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON M5S 3E5 Canada
| | - Kayla Nemr
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON M5S 3E5 Canada
| | - Robert Flick
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON M5S 3E5 Canada
| | - Peter Stogios
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON M5S 3E5 Canada
| | - Alexander F. Yakunin
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON M5S 3E5 Canada
- Centre for Environmental Biotechnology, School of Natural Sciences, Bangor University, Bangor, LL57 2UW UK
| | - Radhakrishnan Mahadevan
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON M5S 3E5 Canada
- Institute of Biomedical Engineering, University of Toronto, 200 College Street, Toronto, ON M5S 3E5 Canada
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Dima RI, Stan G. Computational Studies of Mechanical Remodeling of Substrate Proteins by AAA+ Biological Nanomachines. ACS SYMPOSIUM SERIES 2020. [DOI: 10.1021/bk-2020-1356.ch008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Ruxandra I. Dima
- Department of Chemistry, University of Cincinnati, P. O. Box 210172, Cincinnati, Ohio 45221, United States
| | - George Stan
- Department of Chemistry, University of Cincinnati, P. O. Box 210172, Cincinnati, Ohio 45221, United States
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Abstract
AAA+ proteolytic machines use energy from ATP hydrolysis to degrade damaged, misfolded, or unneeded proteins. Protein degradation occurs within a barrel-shaped self-compartmentalized peptidase. Before protein substrates can enter this peptidase, they must be unfolded and then translocated through the axial pore of an AAA+ ring hexamer. An unstructured region of the protein substrate is initially engaged in the axial pore, and conformational changes in the ring, powered by ATP hydrolysis, generate a mechanical force that pulls on and denatures the substrate. The same conformational changes in the hexameric ring then mediate mechanical translocation of the unfolded polypeptide into the peptidase chamber. For the bacterial ClpXP and ClpAP AAA+ proteases, the mechanical activities of protein unfolding and translocation have been directly visualized by single-molecule optical trapping. These studies in combination with structural and biochemical experiments illuminate many principles that underlie this universal mechanism of ATP-fueled protein unfolding and subsequent destruction.
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Affiliation(s)
- Adrian O Olivares
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
| | - Tania A Baker
- Howard Hughes Medical Institute and Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Robert T Sauer
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA;
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Javidialesaadi A, Flournoy SM, Stan G. Role of Diffusion in Unfolding and Translocation of Multidomain Titin I27 Substrates by a Clp ATPase Nanomachine. J Phys Chem B 2019; 123:2623-2635. [DOI: 10.1021/acs.jpcb.8b10282] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
| | - Shanice M. Flournoy
- Department of Chemistry, Virginia State University, Petersburg, Virginia 23806, United States
| | - George Stan
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
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Bell TA, Baker TA, Sauer RT. Hinge-Linker Elements in the AAA+ Protein Unfoldase ClpX Mediate Intersubunit Communication, Assembly, and Mechanical Activity. Biochemistry 2018; 57:6787-6796. [PMID: 30418765 DOI: 10.1021/acs.biochem.8b00907] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The ClpXP protease plays important roles in protein homeostasis and quality control. ClpX is a ring-shaped AAA+ homohexamer that unfolds target proteins and translocates them into the ClpP peptidase for degradation. AAA+ modules in each ClpX subunit-consisting of a large AAA+ domain, a short hinge-linker element, and a small AAA+ domain-mediate the mechanical activities of the ring hexamer. Here, we investigate the roles of these hinge-linker elements in ClpX function. Deleting one hinge-linker element in a single-chain ClpX pseudohexamer dramatically decreases unfolding and degradation activity, in part by compromising the formation of closed rings, protein-substrate binding, and ClpP binding. Covalently reclosing the broken hinge-linker interface rescues activity. Deleting one hinge-linker element from a single-chain dimer or trimer prevents assembly of stable hexamers. Mutationally disrupting a hinge-linker element preserves closed-ring assembly but reduces ATP-hydrolysis cooperativity and degradation activity. These results indicate that hinge-linker length and flexibility are optimized for efficient substrate unfolding and support a model in which the hinge-linker elements of ClpX facilitate efficient degradation both by maintaining proper ring geometry and facilitating subunit-subunit communication. This model informs our understanding of ClpX as well as the larger AAA+ family of motor proteins, which play diverse roles in converting chemical into mechanical energy in all cells.
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ATPase and Protease Domain Movements in the Bacterial AAA+ Protease FtsH Are Driven by Thermal Fluctuations. J Mol Biol 2018; 430:4592-4602. [PMID: 30044948 DOI: 10.1016/j.jmb.2018.07.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 07/10/2018] [Accepted: 07/17/2018] [Indexed: 01/27/2023]
Abstract
AAA+ proteases are essential players in cellular pathways of protein degradation. Elucidating their conformational behavior is key for understanding their reaction mechanism and, importantly, for elaborating our understanding of mutation-induced protease deficiencies. Here, we study the structural dynamics of the Thermotoga maritima AAA+ hexameric ring metalloprotease FtsH (TmFtsH). Using a single-molecule Förster resonance energy transfer approach to monitor ATPase and protease inter-domain conformational changes in real time, we show that TmFtsH-even in the absence of nucleotide-is a highly dynamic protease undergoing sequential transitions between five states on the second timescale. Addition of ATP does not influence the number of states or change the timescale of domain motions but affects the state occupancy distribution leading to an inter-domain compaction. These findings suggest that thermal energy, but not chemical energy, provides the major driving force for conformational switching, while ATP, through a state reequilibration, introduces directionality into this process. The TmFtsH A359V mutation, a homolog of the human pathogenic A510V mutation of paraplegin (SPG7) causing hereditary spastic paraplegia, does not affect the dynamic behavior of the protease but impairs the ATP-coupled domain compaction and, thus, may account for protease malfunctioning and pathogenesis in hereditary spastic paraplegia.
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Yang Y, Guo R, Gaffney K, Kim M, Muhammednazaar S, Tian W, Wang B, Liang J, Hong H. Folding-Degradation Relationship of a Membrane Protein Mediated by the Universally Conserved ATP-Dependent Protease FtsH. J Am Chem Soc 2018. [PMID: 29528632 DOI: 10.1021/jacs.8b00832] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
ATP-dependent protein degradation mediated by AAA+ proteases is one of the major cellular pathways for protein quality control and regulation of functional networks. While a majority of studies of protein degradation have focused on water-soluble proteins, it is not well understood how membrane proteins with abnormal conformation are selectively degraded. The knowledge gap stems from the lack of an in vitro system in which detailed molecular mechanisms can be studied as well as difficulties in studying membrane protein folding in lipid bilayers. To quantitatively define the folding-degradation relationship of membrane proteins, we reconstituted the degradation using the conserved membrane-integrated AAA+ protease FtsH as a model degradation machine and the stable helical-bundle membrane protein GlpG as a model substrate in the lipid bilayer environment. We demonstrate that FtsH possesses a substantial ability to actively unfold GlpG, and the degradation significantly depends on the stability and hydrophobicity near the degradation marker. We find that FtsH hydrolyzes 380-550 ATP molecules to degrade one copy of GlpG. Remarkably, FtsH overcomes the dual-energetic burden of substrate unfolding and membrane dislocation with the ATP cost comparable to that for water-soluble substrates by robust ClpAP/XP proteases. The physical principles elucidated in this study provide general insights into membrane protein degradation mediated by ATP-dependent proteolytic systems.
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Affiliation(s)
| | | | | | | | | | - Wei Tian
- Department of Bioengineering , University of Illinois at Chicago , Chicago , Illinois 60607 , United States
| | - Boshen Wang
- Department of Bioengineering , University of Illinois at Chicago , Chicago , Illinois 60607 , United States
| | - Jie Liang
- Department of Bioengineering , University of Illinois at Chicago , Chicago , Illinois 60607 , United States
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