1
|
Wan T, Cao Y, Lai YJ, Pan Z, Li YZ, Zhuo L. Functional investigation of the two ClpPs and three ClpXs in Myxococcus xanthus DK1622. mSphere 2024; 9:e0036324. [PMID: 39189774 PMCID: PMC11423568 DOI: 10.1128/msphere.00363-24] [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: 04/29/2024] [Accepted: 07/16/2024] [Indexed: 08/28/2024] Open
Abstract
ClpXP is a protease complex that plays important roles in protein quality control and cell cycle regulation, but the functions of multiple ClpXs and multiple ClpPs in M. xanthus remain unknown. The genome of Myxococcus xanthus DK1622 contains two clpPs and three clpXs. The clpP1 and clpX1 genes are cotranscribed and are both essential, while the other copies are isolated in the genome and are deletable. The deletion of clpX2 caused the mutant to be deficient in fruiting body development, while the clpX3 gene is involved in resistance to thermal stress. Both ClpPs possess catalytic active sites, but only ClpP1 shows in vitro peptidase activity on the typical substrate Suc-LY-AMC. All of these clpP and clpX genes exhibit strong transcriptional upregulation in the stationary phase, and the transcription of the three clpX genes appears to be coordinated. Our results demonstrated that multiple ClpPs and multiple ClpXs are functionally divergent and may assist in the environmental adaptation and functional diversification of M. xanthus.IMPORTANCEClpXP is an important protease complex of bacteria and is involved in various physiological processes. Myxococcus xanthus DK1622 possesses two ClpPs and three ClpXs with unclear functions. We investigated the functions of these genes and demonstrated the essential roles of clpP1 and clpX1. Only ClpP1 has in vitro peptidase activity on Suc-LY-AMC, and the isolated clpX copies participate in distinct cellular processes. All of these genes exhibited significant transcriptional upregulation in the stationary phase. Divergent functions appear in multiple ClpPs and multiple ClpXs in M. xanthus DK1622.
Collapse
Affiliation(s)
- Tianyu Wan
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
| | - Ying Cao
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
| | - Ya-jun Lai
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
| | - Zhuo Pan
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
| | - Yue-zhong Li
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
| | - Li Zhuo
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
- Shenzhen Research Institute, Shandong University, Shenzhen, China
- Suzhou Research Institute, Shandong University, Suzhou, China
| |
Collapse
|
2
|
Iljina M, Mazal H, Dayananda A, Zhang Z, Stan G, Riven I, Haran G. Single-molecule FRET probes allosteric effects on protein-translocating pore loops of a AAA+ machine. Biophys J 2024; 123:374-388. [PMID: 38196191 PMCID: PMC10870172 DOI: 10.1016/j.bpj.2024.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 11/07/2023] [Accepted: 01/02/2024] [Indexed: 01/11/2024] Open
Abstract
AAA+ proteins (ATPases associated with various cellular activities) comprise a family of powerful ring-shaped ATP-dependent translocases that carry out numerous vital substrate-remodeling functions. ClpB is a AAA+ protein disaggregation machine that forms a two-tiered hexameric ring, with flexible pore loops protruding into its center and binding to substrate proteins. It remains unknown whether these pore loops contribute only passively to substrate-protein threading or have a more active role. Recently, we have applied single-molecule FRET spectroscopy to directly measure the dynamics of substrate-binding pore loops in ClpB. We have reported that the three pore loops of ClpB (PL1-3) undergo large-scale fluctuations on the microsecond timescale that are likely to be mechanistically important for disaggregation. Here, using single-molecule FRET, we study the allosteric coupling between the pore loops and the two nucleotide-binding domains of ClpB (NBD1-2). By mutating the conserved Walker B motifs within the NBDs to abolish ATP hydrolysis, we demonstrate how the nucleotide state of each NBD tunes pore-loop dynamics. This effect is surprisingly long-ranged; in particular, PL2 and PL3 respond differentially to a Walker B mutation in either NBD1 or NBD2, as well as to mutations in both. We characterize the conformational dynamics of pore loops and the allosteric paths connecting NBDs to pore loops by molecular dynamics simulations and find that both principal motions and allosteric paths can be altered by changing the ATPase state of ClpB. Remarkably, PL3, which is highly conserved in AAA+ machines, is found to favor an upward conformation when only NBD1 undergoes ATP hydrolysis but a downward conformation when NBD2 is active. These results explicitly demonstrate a significant long-range allosteric effect of ATP hydrolysis sites on pore-loop dynamics. Pore loops are therefore established as active participants that undergo ATP-dependent conformational changes to translocate substrate proteins through the central pores of AAA+ machines.
Collapse
Affiliation(s)
- Marija Iljina
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Hisham Mazal
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Ashan Dayananda
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio
| | - Zhaocheng Zhang
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio
| | - George Stan
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio.
| | - Inbal Riven
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Gilad Haran
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel.
| |
Collapse
|
3
|
Gurung V, Biswas S, Biswas I. Diverse nature of ClpX degradation motifs in Streptococcus mutans. Microbiol Spectr 2024; 12:e0345723. [PMID: 38051052 PMCID: PMC10782952 DOI: 10.1128/spectrum.03457-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 11/07/2023] [Indexed: 12/07/2023] Open
Abstract
IMPORTANCE Cytoplasmic Clp-related proteases play a major role in maintaining cellular proteome in bacteria. ClpX/P is one such proteolytic complex that is important for conserving protein homeostasis. In this study, we investigated the role of ClpX/P in Streptococcus mutans, an important oral pathogen. We identified several putative substrates whose cellular levels are regulated by ClpX/P in S. mutans and subsequently discovered several recognition motifs that are critical for degradation. Our study is the first comprehensive analysis of determining ClpX/P motifs in streptococci. We believe that identifying the substrates that are regulated by ClpX/P will enhance our understanding about virulence regulation in this important group of pathogens.
Collapse
Affiliation(s)
- Vivek Gurung
- Department of Microbiology, Molecular Genetics, and Immunology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Saswati Biswas
- Department of Microbiology, Molecular Genetics, and Immunology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Indranil Biswas
- Department of Microbiology, Molecular Genetics, and Immunology, University of Kansas Medical Center, Kansas City, Kansas, USA
| |
Collapse
|
4
|
Kumari S, Dhara A, Kumar M. Leptospira ClpP mutant variants in association with the ClpX, acyldepsipeptide, and the trigger factor displays unprecedented gain-of-function. Int J Biol Macromol 2024; 254:127753. [PMID: 38287595 DOI: 10.1016/j.ijbiomac.2023.127753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 10/05/2023] [Accepted: 10/27/2023] [Indexed: 01/31/2024]
Abstract
The functionally active ClpP (LinClpP) of Leptospira interrogans is composed of two different isoforms (LinClpP1 and LinClpP2). In this study, five mutants of LinClpP (LinClpP1E170D, LinClpP1N172D, LinClpP2IG_del, LinClpP2S40AK41N, LinClpP2Y62A) targeting its critical hotspot residues were generated. The functional activity of pure LinClpP mutant variants or its heterocomplex and its effect when associated with a chaperone (LinClpX)/antibiotic acyldepsipeptide (ADEP1)/trigger factor (LinTF) was examined. The two mutants (LinClpP2S40AK41N and LinClpP2Y62A) displayed gain-of-function (GOF) in peptidase activity. The ADEP1-bound heterocomplex (LinClpP1P2S40AK41N and LinClpP1P2Y62A) measured 1.7 and 1.5-fold higher protease activity than ADEP-bound LinClpP1P2. The dynamic light scattering analysis of ADEP1-bound GOF mutants displayed increased hydrodynamic diameter. In the presence of LinTF, the heterocomplex (LinClpP1P2S40AK41N and LinClpP1P2Y62A) exhibited a 3-fold surge in peptidase activity. The deletion mutant (LinClpP2IG_del) or its heterocomplex (LinClpP1P2IG_del) displayed no activity. Similarly, the pure LinClpP1E170D and LinClpP1N172D could not cleave a model dipeptide. However, its heterocomplex (LinClpP1E170DP2 and LinClpP1N172DP2) showed 0.5-fold lower peptidase activity than the LinClpP1P2. Collectively, two mutants (LinClpP2S40AK41N and LinClpP2Y62A) have GOF and can degrade model dipeptide substrate without the aid of LinClpP1 isoform and thus provide new insights into unprecedented LinClpP activation.
Collapse
Affiliation(s)
- Surbhi Kumari
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Anusua Dhara
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Manish Kumar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India.
| |
Collapse
|
5
|
Henriksen C, Baek KT, Wacnik K, Gallay C, Veening JW, Foster SJ, Frees D. The ClpX chaperone and a hypermorphic FtsA variant with impaired self-interaction are mutually compensatory for coordinating Staphylococcus aureus cell division. Mol Microbiol 2024; 121:98-115. [PMID: 38041395 DOI: 10.1111/mmi.15200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 11/13/2023] [Accepted: 11/13/2023] [Indexed: 12/03/2023]
Abstract
Bacterial cell division requires the coordinated assembly and disassembly of a large protein complex called the divisome; however, the exact role of molecular chaperones in this critical process remains unclear. We here provide genetic evidence that ClpX unfoldase activity is a determinant for proper coordination of bacterial cell division by showing the growth defect of a Staphylococcus aureus clpX mutant is rescued by a spontaneously acquired G325V substitution in the ATP-binding domain of the essential FtsA cell division protein. The polymerization state of FtsA is thought to control initiation of bacterial septum synthesis and, while restoring the aberrant FtsA dynamics in clpX cells, the FtsAG325V variant displayed reduced ability to interact with itself and other cell division proteins. In wild-type cells, the ftsAG325V allele shared phenotypes with Escherichia coli superfission ftsA mutants and accelerated the cell cycle, increased the risk of daughter cell lysis, and conferred sensitivity to heat and antibiotics inhibiting cell wall synthesis. Strikingly, lethality was mitigated by spontaneous mutations that inactivate ClpX. Taken together, our results suggest that ClpX promotes septum synthesis by antagonizing FtsA interactions and illuminates the critical role of a protein unfoldase in coordinating bacterial cell division.
Collapse
Affiliation(s)
- Camilla Henriksen
- Department of Veterinary and Animal Disease, University of Copenhagen, Frederiksberg, Denmark
| | - Kristoffer T Baek
- Department of Veterinary and Animal Disease, University of Copenhagen, Frederiksberg, Denmark
| | | | - Clement Gallay
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Jan-Willem Veening
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Simon J Foster
- School of Biosciences, University of Sheffield, Sheffield, UK
| | - Dorte Frees
- Department of Veterinary and Animal Disease, University of Copenhagen, Frederiksberg, Denmark
| |
Collapse
|
6
|
Dow LF, Case AM, Paustian MP, Pinkerton BR, Simeon P, Trippier PC. The evolution of small molecule enzyme activators. RSC Med Chem 2023; 14:2206-2230. [PMID: 37974956 PMCID: PMC10650962 DOI: 10.1039/d3md00399j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 09/20/2023] [Indexed: 11/19/2023] Open
Abstract
There is a myriad of enzymes within the body responsible for maintaining homeostasis by providing the means to convert substrates to products as and when required. Physiological enzymes are tightly controlled by many signaling pathways and their products subsequently control other pathways. Traditionally, most drug discovery efforts focus on identifying enzyme inhibitors, due to upregulation being prevalent in many diseases and the existence of endogenous substrates that can be modified to afford inhibitor compounds. As enzyme downregulation and reduction of endogenous activators are observed in multiple diseases, the identification of small molecules with the ability to activate enzymes has recently entered the medicinal chemistry toolbox to afford chemical probes and potential therapeutics as an alternative means to intervene in diseases. In this review we highlight the progress made in the identification and advancement of non-kinase enzyme activators and their potential in treating various disease states.
Collapse
Affiliation(s)
- Louise F Dow
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center Omaha NE 68106 USA
| | - Alfie M Case
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center Omaha NE 68106 USA
| | - Megan P Paustian
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center Omaha NE 68106 USA
| | - Braeden R Pinkerton
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center Omaha NE 68106 USA
| | - Princess Simeon
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center Omaha NE 68106 USA
| | - Paul C Trippier
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center Omaha NE 68106 USA
- Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center Omaha NE 68106 USA
- UNMC Center for Drug Discovery, University of Nebraska Medical Center Omaha NE 68106 USA
| |
Collapse
|
7
|
The SspB adaptor drives structural changes in the AAA+ ClpXP protease during ssrA-tagged substrate delivery. Proc Natl Acad Sci U S A 2023; 120:e2219044120. [PMID: 36730206 PMCID: PMC9963277 DOI: 10.1073/pnas.2219044120] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Energy-dependent protein degradation by the AAA+ ClpXP protease helps maintain protein homeostasis in bacteria and eukaryotic organelles of bacterial origin. In Escherichia coli and many other proteobacteria, the SspB adaptor assists ClpXP in degrading ssrA-tagged polypeptides produced as a consequence of tmRNA-mediated ribosome rescue. By tethering these incomplete ssrA-tagged proteins to ClpXP, SspB facilitates their efficient degradation at low substrate concentrations. How this process occurs structurally is unknown. Here, we present a cryo-EM structure of the SspB adaptor bound to a GFP-ssrA substrate and to ClpXP. This structure provides evidence for simultaneous contacts of SspB and ClpX with the ssrA tag within the tethering complex, allowing direct substrate handoff concomitant with the initiation of substrate translocation. Furthermore, our structure reveals that binding of the substrate·adaptor complex induces unexpected conformational changes within the spiral structure of the AAA+ ClpX hexamer and its interaction with the ClpP tetradecamer.
Collapse
|
8
|
Abstract
Secretory proteins are cotranslationally or posttranslationally translocated across lipid membranes via a protein-conducting channel named SecY in prokaryotes and Sec61 in eukaryotes. The vast majority of secretory proteins in bacteria are driven through the channel posttranslationally by SecA, a highly conserved ATPase. How a polypeptide chain is moved by SecA through the SecY channel is poorly understood. Here, we report electron cryomicroscopy structures of the active SecA-SecY translocon with a polypeptide substrate. The substrate is captured in different translocation states when clamped by SecA with different nucleotides. Upon binding of an ATP analog, SecA undergoes global conformational changes to push the polypeptide substrate toward the channel in a way similar to how the RecA-like helicases translocate their nucleic acid substrates. The movements of the polypeptide substrates in the SecA-SecY translocon share a similar structural basis to those in the ribosome-SecY complex during cotranslational translocation.
Collapse
|
9
|
Macke AC, Kelly MS, Varikoti RA, Mullen S, Groves D, Forbes C, Dima RI. Microtubule Severing Enzymes Oligomerization and Allostery: A Tale of Two Domains. J Phys Chem B 2022; 126:10569-10586. [PMID: 36475672 DOI: 10.1021/acs.jpcb.2c05288] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Severing proteins are nanomachines from the AAA+ (ATPases associated with various cellular activities) superfamily whose function is to remodel the largest cellular filaments, microtubules. The standard AAA+ machines adopt hexameric ring structures for functional reasons, while being primarily monomeric in the absence of the nucleotide. Both major severing proteins, katanin and spastin, are believed to follow this trend. However, studies proposed that they populate lower-order oligomers in the presence of cofactors, which are functionally relevant. Our simulations show that the preferred oligomeric assembly is dependent on the binding partners and on the type of severing protein. Essential dynamics analysis predicts that the stability of an oligomer is dependent on the strength of the interface between the helical bundle domain (HBD) of a monomer and the convex face of the nucleotide binding domain (NBD) of a neighboring monomer. Hot spots analysis found that the region consisting of the HBD tip and the C-terminal (CT) helix is the only common element between the allosteric networks responding to nucleotide, substrate, and intermonomer binding. Clustering analysis indicates the existence of multiple pathways for the transition between the secondary structure of the HBD tip in monomers and the structure(s) it adopts in oligomers.
Collapse
Affiliation(s)
- Amanda C Macke
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Maria S Kelly
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Rohith Anand Varikoti
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Sarah Mullen
- Department of Chemistry, The College of Wooster, Wooster, Ohio 44691, United States
- Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Daniel Groves
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Clare Forbes
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Ruxandra I Dima
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| |
Collapse
|
10
|
Xu W, Gao W, Bu Q, Li Y. Degradation Mechanism of AAA+ Proteases and Regulation of Streptomyces Metabolism. Biomolecules 2022; 12:biom12121848. [PMID: 36551276 PMCID: PMC9775585 DOI: 10.3390/biom12121848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 12/02/2022] [Accepted: 12/08/2022] [Indexed: 12/14/2022] Open
Abstract
Hundreds of proteins work together in microorganisms to coordinate and control normal activity in cells. Their degradation is not only the last step in the cell's lifespan but also the starting point for its recycling. In recent years, protein degradation has been extensively studied in both eukaryotic and prokaryotic organisms. Understanding the degradation process is essential for revealing the complex regulatory network in microorganisms, as well as further artificial reconstructions and applications. This review will discuss several studies on protein quality-control family members Lon, FtsH, ClpP, the proteasome in Streptomyces, and a few classical model organisms, mainly focusing on their structure, recognition mechanisms, and metabolic influences.
Collapse
Affiliation(s)
- Weifeng Xu
- Institute of Pharmaceutical Biotechnology, Zhejiang University School of Medicine, Hangzhou 310058, China
- Zhejiang Provincial Key Laboratory for Microbial Biochemistry and Metabolic Engineering, Hangzhou 310058, China
| | - Wenli Gao
- Institute of Pharmaceutical Biotechnology, Zhejiang University School of Medicine, Hangzhou 310058, China
- Zhejiang Provincial Key Laboratory for Microbial Biochemistry and Metabolic Engineering, Hangzhou 310058, China
| | - Qingting Bu
- Institute of Pharmaceutical Biotechnology, Zhejiang University School of Medicine, Hangzhou 310058, China
- Zhejiang Provincial Key Laboratory for Microbial Biochemistry and Metabolic Engineering, Hangzhou 310058, China
| | - Yongquan Li
- Institute of Pharmaceutical Biotechnology, Zhejiang University School of Medicine, Hangzhou 310058, China
- Zhejiang Provincial Key Laboratory for Microbial Biochemistry and Metabolic Engineering, Hangzhou 310058, China
- Correspondence:
| |
Collapse
|
11
|
Aljghami ME, Barghash MM, Majaesic E, Bhandari V, Houry WA. Cellular functions of the ClpP protease impacting bacterial virulence. Front Mol Biosci 2022; 9:1054408. [PMID: 36533084 PMCID: PMC9753991 DOI: 10.3389/fmolb.2022.1054408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 11/15/2022] [Indexed: 09/28/2023] Open
Abstract
Proteostasis mechanisms significantly contribute to the sculpting of the proteomes of all living organisms. ClpXP is a central AAA+ chaperone-protease complex present in both prokaryotes and eukaryotes that facilitates the unfolding and subsequent degradation of target substrates. ClpX is a hexameric unfoldase ATPase, while ClpP is a tetradecameric serine protease. Substrates of ClpXP belong to many cellular pathways such as DNA damage response, metabolism, and transcriptional regulation. Crucially, disruption of this proteolytic complex in microbes has been shown to impact the virulence and infectivity of various human pathogenic bacteria. Loss of ClpXP impacts stress responses, biofilm formation, and virulence effector protein production, leading to decreased pathogenicity in cell and animal infection models. Here, we provide an overview of the multiple critical functions of ClpXP and its substrates that modulate bacterial virulence with examples from several important human pathogens.
Collapse
Affiliation(s)
- Mazen E. Aljghami
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Marim M. Barghash
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Emily Majaesic
- Department of Chemistry, University of Toronto, Toronto, ON, Canada
| | - Vaibhav Bhandari
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Walid A. Houry
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
- Department of Chemistry, University of Toronto, Toronto, ON, Canada
| |
Collapse
|
12
|
Abstract
Despite having a highly reduced genome, Chlamydia trachomatis undergoes a complex developmental cycle in which the bacteria differentiate between the following two functionally and morphologically distinct forms: the infectious, nonreplicative elementary body (EB) and the noninfectious, replicative reticulate body (RB). The transitions between EBs and RBs are not mediated by division events that redistribute intracellular proteins. Rather, both primary (EB to RB) and secondary (RB to EB) differentiation likely require bulk protein turnover. One system for targeted protein degradation is the trans-translation system for ribosomal rescue, where polypeptides stalled during translation are marked with an SsrA tag encoded by a hybrid tRNA-mRNA, tmRNA. ClpX recognizes the SsrA tag, leading to ClpXP-mediated degradation. We hypothesize that ClpX functions in chlamydial differentiation through targeted protein degradation. We found that mutation of a key residue (R230A) within the specific motif in ClpX associated with the recognition of SsrA-tagged substrates resulted in abrogated secondary differentiation while not reducing chlamydial replication or developmental cycle progression as measured by transcripts. Furthermore, inhibition of trans-translation through chemical and targeted genetic approaches also impeded chlamydial development. Knockdown of tmRNA and subsequent complementation with an allele mutated in the SsrA tag closely phenocopied the overexpression of ClpXR230A, thus suggesting that ClpX recognition of SsrA-tagged substrates plays a critical function in secondary differentiation. Taken together, these data provide mechanistic insight into the requirements for transitions between chlamydial developmental forms. IMPORTANCE Chlamydia trachomatis is the leading cause of bacterial sexually transmitted infections and preventable infectious blindness. This unique organism undergoes developmental transitions between infectious, nondividing forms and noninfectious, dividing forms. Therefore, the chlamydial developmental cycle is an attractive target for Chlamydia-specific antibiotics, which would minimize effects of broad-spectrum antibiotics on the spread of antibiotic resistance in other organisms. However, the lack of knowledge about chlamydial development on a molecular level impedes the identification of specific, druggable targets. This work describes a mechanism through which both the fundamental processes of trans-translation and proteomic turnover by ClpXP contribute to chlamydial differentiation, a critical facet of chlamydial growth and survival. Given the almost universal presence of trans-translation and ClpX in eubacteria, this mechanism may be conserved in developmental cycles of other bacterial species. Additionally, this study expands the fields of trans-translation and Clp proteases by emphasizing the functional diversity of these systems throughout bacterial evolution.
Collapse
|
13
|
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.
Collapse
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.
| |
Collapse
|
14
|
Mahmoud SA, Aldikacti B, Chien P. ATP hydrolysis tunes specificity of a AAA+ protease. Cell Rep 2022; 40:111405. [PMID: 36130509 DOI: 10.1016/j.celrep.2022.111405] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 05/27/2022] [Accepted: 09/01/2022] [Indexed: 11/16/2022] Open
Abstract
In bacteria, AAA+ proteases such as Lon and ClpXP degrade substrates with exquisite specificity. These machines capture the energy of ATP hydrolysis to power unfolding and degradation of target substrates. Here, we show that a mutation in the ATP binding site of ClpX shifts protease specificity to promote degradation of normally Lon-restricted substrates. However, this ClpX mutant is worse at degrading ClpXP targets, suggesting an optimal balance in substrate preference for a given protease that is easy to alter. In vitro, wild-type ClpXP also degrades Lon-restricted substrates more readily when ATP levels are reduced, similar to the shifted specificity of mutant ClpXP, which has altered ATP hydrolysis kinetics. Based on these results, we suggest that the rates of ATP hydrolysis not only power substrate unfolding and degradation, but also tune protease specificity. We consider various models for this effect based on emerging structures of AAA+ machines showing conformationally distinct states.
Collapse
Affiliation(s)
- Samar A Mahmoud
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, MA 01003, USA; Molecular and Cellular Biology Program, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Berent Aldikacti
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, MA 01003, USA; Molecular and Cellular Biology Program, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Peter Chien
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, MA 01003, USA; Molecular and Cellular Biology Program, University of Massachusetts Amherst, Amherst, MA 01003, USA.
| |
Collapse
|
15
|
Kudzhaev AM, Andrianova AG, Gustchina AE, Smirnov IV, Rotanova TV. ATP-Dependent Lon Proteases in the Cellular Protein Quality Control System. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2022. [DOI: 10.1134/s1068162022040136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
16
|
Varikoti RA, Fonseka HYY, Kelly MS, Javidi A, Damre M, Mullen S, Nugent JL, Gonzales CM, Stan G, Dima RI. Exploring the Effect of Mechanical Anisotropy of Protein Structures in the Unfoldase Mechanism of AAA+ Molecular Machines. NANOMATERIALS 2022; 12:nano12111849. [PMID: 35683705 PMCID: PMC9182431 DOI: 10.3390/nano12111849] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Revised: 05/25/2022] [Accepted: 05/25/2022] [Indexed: 02/06/2023]
Abstract
Essential cellular processes of microtubule disassembly and protein degradation, which span lengths from tens of μm to nm, are mediated by specialized molecular machines with similar hexameric structure and function. Our molecular simulations at atomistic and coarse-grained scales show that both the microtubule-severing protein spastin and the caseinolytic protease ClpY, accomplish spectacular unfolding of their diverse substrates, a microtubule lattice and dihydrofolate reductase (DHFR), by taking advantage of mechanical anisotropy in these proteins. Unfolding of wild-type DHFR requires disruption of mechanically strong β-sheet interfaces near each terminal, which yields branched pathways associated with unzipping along soft directions and shearing along strong directions. By contrast, unfolding of circular permutant DHFR variants involves single pathways due to softer mechanical interfaces near terminals, but translocation hindrance can arise from mechanical resistance of partially unfolded intermediates stabilized by β-sheets. For spastin, optimal severing action initiated by pulling on a tubulin subunit is achieved through specific orientation of the machine versus the substrate (microtubule lattice). Moreover, changes in the strength of the interactions between spastin and a microtubule filament, which can be driven by the tubulin code, lead to drastically different outcomes for the integrity of the hexameric structure of the machine.
Collapse
Affiliation(s)
- Rohith Anand Varikoti
- Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221, USA; (R.A.V.); (H.Y.Y.F.); (M.S.K.); (M.D.); (J.L.N.IV)
| | - Hewafonsekage Yasan Y. Fonseka
- Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221, USA; (R.A.V.); (H.Y.Y.F.); (M.S.K.); (M.D.); (J.L.N.IV)
| | - Maria S. Kelly
- Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221, USA; (R.A.V.); (H.Y.Y.F.); (M.S.K.); (M.D.); (J.L.N.IV)
| | - Alex Javidi
- Data Sciences, Janssen Research and Development, Spring House, PA 19477, USA;
| | - Mangesh Damre
- Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221, USA; (R.A.V.); (H.Y.Y.F.); (M.S.K.); (M.D.); (J.L.N.IV)
| | - Sarah Mullen
- Department of Chemistry, The College of Wooster, Wooster, OH 44691, USA;
| | - Jimmie L. Nugent
- Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221, USA; (R.A.V.); (H.Y.Y.F.); (M.S.K.); (M.D.); (J.L.N.IV)
| | | | - George Stan
- Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221, USA; (R.A.V.); (H.Y.Y.F.); (M.S.K.); (M.D.); (J.L.N.IV)
- Correspondence: (G.S.); (R.I.D.)
| | - Ruxandra I. Dima
- Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221, USA; (R.A.V.); (H.Y.Y.F.); (M.S.K.); (M.D.); (J.L.N.IV)
- Correspondence: (G.S.); (R.I.D.)
| |
Collapse
|
17
|
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.
Collapse
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
| |
Collapse
|
18
|
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.
Collapse
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.
| |
Collapse
|
19
|
Brady MM, Meyer AS. Cataloguing the proteome: Current developments in single-molecule protein sequencing. BIOPHYSICS REVIEWS 2022; 3:011304. [PMID: 38505228 PMCID: PMC10903494 DOI: 10.1063/5.0065509] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 01/13/2022] [Indexed: 03/21/2024]
Abstract
The cellular proteome is complex and dynamic, with proteins playing a critical role in cell-level biological processes that contribute to homeostasis, stimuli response, and disease pathology, among others. As such, protein analysis and characterization are of extreme importance in both research and clinical settings. In the last few decades, most proteomics analysis has relied on mass spectrometry, affinity reagents, or some combination thereof. However, these techniques are limited by their requirements for large sample amounts, low resolution, and insufficient dynamic range, making them largely insufficient for the characterization of proteins in low-abundance or single-cell proteomic analysis. Despite unique technical challenges, several single-molecule protein sequencing (SMPS) technologies have been proposed in recent years to address these issues. In this review, we outline several approaches to SMPS technologies and discuss their advantages, limitations, and potential contributions toward an accurate, sensitive, and high-throughput platform.
Collapse
Affiliation(s)
- Morgan M. Brady
- Department of Biology, University of Rochester, Rochester, New York 14627, USA
| | - Anne S. Meyer
- Department of Biology, University of Rochester, Rochester, New York 14627, USA
| |
Collapse
|
20
|
Kumar T, Maitra S, Rahman A, Bhattacharjee S. A conserved guided entry of tail-anchored pathway is involved in the trafficking of a subset of membrane proteins in Plasmodium falciparum. PLoS Pathog 2021; 17:e1009595. [PMID: 34780541 PMCID: PMC8629386 DOI: 10.1371/journal.ppat.1009595] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 11/29/2021] [Accepted: 10/19/2021] [Indexed: 01/22/2023] Open
Abstract
Tail-anchored (TA) proteins are defined by the absence of N-terminus signal sequence and the presence of a single transmembrane domain (TMD) proximal to their C-terminus. They play fundamental roles in cellular processes including vesicular trafficking, protein translocation and quality control. Some of the TA proteins are post-translationally integrated by the Guided Entry of TA (GET) pathway to the cellular membranes; with their N-terminus oriented towards the cytosol and C-terminus facing the organellar lumen. The TA repertoire and the GET machinery have been extensively characterized in the yeast and mammalian systems, however, they remain elusive in the human malaria parasite Plasmodium falciparum. In this study, we bioinformatically predicted a total of 63 TA proteins in the P. falciparum proteome and revealed the association of a subset with the P. falciparum homolog of Get3 (PfGet3). In addition, our proximity labelling studies either definitively identified or shortlisted the other eligible GET constituents, and our in vitro association studies validated associations between PfGet3 and the corresponding homologs of Get4 and Get2 in P. falciparum. Collectively, this study reveals the presence of proteins with hallmark TA signatures and the involvement of evolutionary conserved GET trafficking pathway for their targeted delivery within the parasite. Tail-anchored (TA) membrane proteins are known to play essential cellular functions in the eukaryotes. These proteins are trafficked to their respective destinations by post-translational translocation pathways that are evolutionarily conserved from yeast to human. However, they remain unidentified in the malaria parasite Plasmodium falciparum. We have used bioinformatic prediction algorithms in conjunction with functional validation studies to identify the candidate TA repertoire and some of the homologs of the trafficking machinery in P. falciparum. Initially, we predicted the presence of 63 putative TA proteins localized to distinct compartments within this parasite, including a few confirmed TA homologs in other eukaryotic systems. We then identified and characterized PfGet3 as a central component in the Guided-Entry of TA (GET) translocation machinery, and our bacterial co-expression and pulldown assays with two selected recombinant TA proteins, PfBOS1 and PfUSE1, showed co-association with PfGet3. We also identified PfGet2 and PfGet4 as the other two components of the GET machinery in P. falciparum using proximity biotinylation followed by mass spectrometry. Interestingly, we also found six TA proteins in the parasite enriched in this fraction. We further validated the direct interactions between a few TA candidates, PfGet4 and PfGet2 with PfGet3 using recombinant-based pulldown studies. In conclusion, this study classified a subset of membrane proteins with the TA nomenclature and implicated a previously unidentified GET pathway for their translocation in this apicomplexan parasite.
Collapse
Affiliation(s)
- Tarkeshwar Kumar
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
| | - Satarupa Maitra
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
| | - Abdur Rahman
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
| | - Souvik Bhattacharjee
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
- * E-mail:
| |
Collapse
|
21
|
Division of labor between the pore-1 loops of the D1 and D2 AAA+ rings coordinates substrate selectivity of the ClpAP protease. J Biol Chem 2021; 297:101407. [PMID: 34780718 PMCID: PMC8666677 DOI: 10.1016/j.jbc.2021.101407] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 11/06/2021] [Accepted: 11/08/2021] [Indexed: 11/24/2022] Open
Abstract
ClpAP, an ATP-dependent protease consisting of ClpA, a double-ring hexameric unfoldase of the ATPases associated with diverse cellular activities superfamily, and the ClpP peptidase, degrades damaged and unneeded proteins to support cellular proteostasis. ClpA recognizes many protein substrates directly, but it can also be regulated by an adapter, ClpS, that modifies ClpA’s substrate profile toward N-degron substrates. Conserved tyrosines in the 12 pore-1 loops lining the central channel of the stacked D1 and D2 rings of ClpA are critical for degradation, but the roles of these residues in individual steps during direct or adapter-mediated degradation are poorly understood. Using engineered ClpA hexamers with zero, three, or six pore-1 loop mutations in each ATPases associated with diverse cellular activities superfamily ring, we found that active D1 pore loops initiate productive engagement of substrates, whereas active D2 pore loops are most important for mediating the robust unfolding of stable native substrates. In complex with ClpS, active D1 pore loops are required to form a high affinity ClpA•ClpS•substrate complex, but D2 pore loops are needed to “tug on” and remodel ClpS to transfer the N-degron substrate to ClpA. Overall, we find that the pore-1 loop tyrosines in D1 are critical for direct substrate engagement, whereas ClpS-mediated substrate delivery requires unique contributions from both the D1 and D2 pore loops. In conclusion, our study illustrates how pore loop engagement, substrate capture, and powering of the unfolding/translocation steps are distributed between the two rings of ClpA, illuminating new mechanistic features that may be common to double-ring protein unfolding machines.
Collapse
|
22
|
Fonseka HYY, Javidi A, Oliveira LFL, Micheletti C, Stan G. Unfolding and Translocation of Knotted Proteins by Clp Biological Nanomachines: Synergistic Contribution of Primary Sequence and Topology Revealed by Molecular Dynamics Simulations. J Phys Chem B 2021; 125:7335-7350. [PMID: 34110163 DOI: 10.1021/acs.jpcb.1c00898] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We use Langevin dynamics simulations to model, at an atomistic resolution, how various natively knotted proteins are unfolded in repeated allosteric translocating cycles of the ClpY ATPase. We consider proteins representative of different topologies, from the simplest knot (trefoil 31), to the three-twist 52 knot, to the most complex stevedore, 61, knot. We harness the atomistic detail of the simulations to address aspects that have so far remained largely unexplored, such as sequence-dependent effects on the ruggedness of the landscape traversed during knot sliding. Our simulations reveal the combined effect on translocation of the knotted protein structure, i.e., backbone topology and geometry, and primary sequence, i.e., side chain size and interactions, and show that the latter can dominate translocation hindrance. In addition, we observe that due to the interplay between the knotted topology and intramolecular contacts the transmission of tension along the polypeptide chain occurs very differently from that of homopolymers. Finally, by considering native and non-native interactions, we examine how the disruption or formation of such contacts can affect the translocation processivity and concomitantly create multiple unfolding pathways with very different activation barriers.
Collapse
Affiliation(s)
| | - Alex Javidi
- Data Sciences, Janssen Research and Development, Spring House, Pennsylvania 19477, United States
| | - Luiz F L Oliveira
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Cristian Micheletti
- Molecular and Statistical Biophysics, Scuola Internazionale Superiore di Studi Avanzati (SISSA), 34136 Trieste, Italy
| | - George Stan
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| |
Collapse
|
23
|
Song R, Qiao W, He J, Huang J, Luo Y, Yang T. Proteases and Their Modulators in Cancer Therapy: Challenges and Opportunities. J Med Chem 2021; 64:2851-2877. [PMID: 33656892 DOI: 10.1021/acs.jmedchem.0c01640] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Proteostasis is the process of regulating intracellular proteins to maintain the balance of the cell proteome, which is crucial for cancer cell survival. Several proteases located in the cytoplasm, mitochondria, lysosome, and extracellular environment have been identified as potential antitumor targets because of their involvement in proteostasis. Although the discovery of small-molecule inhibitors targeting proteases faces particular challenges, rapid advances in chemical biology and structural biology, and the new technology of drug discovery have facilitated the development of promising protease modulators. In this review, the protein structure and function of important tumor-related proteases and their inhibitors are presented. We also provide a prospective on advances and the outlook of new drug strategies that target these proteases.
Collapse
Affiliation(s)
- Rao Song
- State Key Laboratory of Biotherapy and Cancer Center/Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Wenliang Qiao
- Lung Cancer Center, Laboratory of Lung Cancer, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Jun He
- State Key Laboratory of Biotherapy and Cancer Center/Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Jiasheng Huang
- State Key Laboratory of Biotherapy and Cancer Center/Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Youfu Luo
- State Key Laboratory of Biotherapy and Cancer Center/Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Tao Yang
- State Key Laboratory of Biotherapy and Cancer Center/Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China.,Laboratory of Human Disease and Immunotherapies, West China Hospital, Sichuan University, Chengdu 610041, China
| |
Collapse
|
24
|
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.
Collapse
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.
| |
Collapse
|
25
|
Polymerase delta-interacting protein 38 (PDIP38) modulates the stability and activity of the mitochondrial AAA+ protease CLPXP. Commun Biol 2020; 3:646. [PMID: 33159171 PMCID: PMC7647994 DOI: 10.1038/s42003-020-01358-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 10/09/2020] [Indexed: 02/06/2023] Open
Abstract
Over a decade ago Polymerase δ interacting protein of 38 kDa (PDIP38) was proposed to play a role in DNA repair. Since this time, both the physiological function and subcellular location of PDIP38 has remained ambiguous and our present understanding of PDIP38 function has been hampered by a lack of detailed biochemical and structural studies. Here we show, that human PDIP38 is directed to the mitochondrion in a membrane potential dependent manner, where it resides in the matrix compartment, together with its partner protein CLPX. Our structural analysis revealed that PDIP38 is composed of two conserved domains separated by an α/β linker region. The N-terminal (YccV-like) domain of PDIP38 forms an SH3-like β-barrel, which interacts specifically with CLPX, via the adaptor docking loop within the N-terminal Zinc binding domain of CLPX. In contrast, the C-terminal (DUF525) domain forms an immunoglobin-like β-sandwich fold, which contains a highly conserved putative substrate binding pocket. Importantly, PDIP38 modulates the substrate specificity of CLPX and protects CLPX from LONM-mediated degradation, which stabilises the cellular levels of CLPX. Collectively, our findings shed new light on the mechanism and function of mitochondrial PDIP38, demonstrating that PDIP38 is a bona fide adaptor protein for the mitochondrial protease, CLPXP. Strack et al find that Polymerase δ interacting protein 38 (PDIP38) is targeted to the mitochondrial matrix where it colocalises with the mitochondrial AAA + protein CLPXP. PDIP38 modulates the specificity of CLPXP in vitro and alters the stability of CLPX in vitro and in cells. The PDIP38 structure leads the authors to speculate that PDIP38 is a CLPXP adaptor.
Collapse
|
26
|
Ropelewska M, Gross MH, Konieczny I. DNA and Polyphosphate in Directed Proteolysis for DNA Replication Control. Front Microbiol 2020; 11:585717. [PMID: 33123115 PMCID: PMC7566177 DOI: 10.3389/fmicb.2020.585717] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 09/10/2020] [Indexed: 12/03/2022] Open
Abstract
The strict control of bacterial cell proliferation by proteolysis is vital to coordinate cell cycle processes and to adapt to environmental changes. ATP-dependent proteases of the AAA + family are molecular machineries that contribute to cellular proteostasis. Their activity is important to control the level of various proteins, including those that are essential for the regulation of DNA replication. Since the process of proteolysis is irreversible, the protease activity must be tightly regulated and directed toward a specific substrate at the exact time and space in a cell. In our mini review, we discuss the impact of phosphate-containing molecules like DNA and inorganic polyphosphate (PolyP), accumulated during stress, on protease activities. We describe how the directed proteolysis of essential replication proteins contributes to the regulation of DNA replication under normal and stress conditions in bacteria.
Collapse
Affiliation(s)
- Malgorzata Ropelewska
- Laboratory of Molecular Biology, Intercollegiate Faculty of Biotechnology of University of Gdańsk and Medical University of Gdańsk, Gdańsk, Poland
| | - Marta H Gross
- Laboratory of Molecular Biology, Intercollegiate Faculty of Biotechnology of University of Gdańsk and Medical University of Gdańsk, Gdańsk, Poland
| | - Igor Konieczny
- Laboratory of Molecular Biology, Intercollegiate Faculty of Biotechnology of University of Gdańsk and Medical University of Gdańsk, Gdańsk, Poland
| |
Collapse
|
27
|
Fei X, Bell TA, Barkow SR, Baker TA, Sauer RT. Structural basis of ClpXP recognition and unfolding of ssrA-tagged substrates. eLife 2020; 9:61496. [PMID: 33089779 PMCID: PMC7652416 DOI: 10.7554/elife.61496] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 10/21/2020] [Indexed: 01/05/2023] Open
Abstract
When ribosomes fail to complete normal translation, all cells have mechanisms to ensure degradation of the resulting partial proteins to safeguard proteome integrity. In Escherichia coli and other eubacteria, the tmRNA system rescues stalled ribosomes and adds an ssrA tag or degron to the C-terminus of the incomplete protein, which directs degradation by the AAA+ ClpXP protease. Here, we present cryo-EM structures of ClpXP bound to the ssrA degron. C-terminal residues of the ssrA degron initially bind in the top of an otherwise closed ClpX axial channel and subsequently move deeper into an open channel. For short-degron protein substrates, we show that unfolding can occur directly from the initial closed-channel complex. For longer degron substrates, our studies illuminate how ClpXP transitions from specific recognition into a nonspecific unfolding and translocation machine. Many AAA+ proteases and protein-remodeling motors are likely to employ similar multistep recognition and engagement strategies.
Collapse
Affiliation(s)
- Xue Fei
- Departments of Biology, Massachusetts Institute of Technology, Cambridge, United States
| | - Tristan A Bell
- Departments of Biology, Massachusetts Institute of Technology, Cambridge, United States
| | - Sarah R Barkow
- Chemistry, Massachusetts Institute of Technology, Cambridge, United States
| | - Tania A Baker
- Departments of Biology, Massachusetts Institute of Technology, Cambridge, United States
| | - Robert T Sauer
- Departments of Biology, Massachusetts Institute of Technology, Cambridge, United States
| |
Collapse
|
28
|
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
| |
Collapse
|
29
|
The ClpX and ClpP2 Orthologs of Chlamydia trachomatis Perform Discrete and Essential Functions in Organism Growth and Development. mBio 2020; 11:mBio.02016-20. [PMID: 32873765 PMCID: PMC7468207 DOI: 10.1128/mbio.02016-20] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Chlamydia trachomatis is the leading cause of infectious blindness globally and the most reported bacterial sexually transmitted infection both domestically and internationally. Given the economic burden, the lack of an approved vaccine, and the use of broad-spectrum antibiotics for treatment of infections, an understanding of chlamydial growth and development is critical for the advancement of novel targeted antibiotics. The Clp proteins comprise an important and conserved protease system in bacteria. Our work highlights the importance of the chlamydial Clp proteins to this clinically important bacterium. Additionally, our study implicates the Clp system playing an integral role in chlamydial developmental cycle progression, which may help establish models of how Chlamydia spp. and other bacteria progress through their respective developmental cycles. Our work also contributes to a growing body of Clp-specific research that underscores the importance and versatility of this system throughout bacterial evolution and further validates Clp proteins as drug targets. Chlamydia trachomatis is an obligate intracellular bacterium that undergoes a complex developmental cycle in which the bacterium differentiates between two functionally and morphologically distinct forms, the elementary body (EB) and reticulate body (RB), each of which expresses its own specialized repertoire of proteins. Both primary (EB to RB) and secondary (RB to EB) differentiations require protein turnover, and we hypothesize that proteases are critical for mediating differentiation. The Clp protease system is well conserved in bacteria and important for protein turnover. Minimally, the system relies on a serine protease subunit, ClpP, and an AAA+ ATPase, such as ClpX, that recognizes and unfolds substrates for ClpP degradation. In Chlamydia, ClpX is encoded within an operon 3′ to clpP2. We present evidence that the chlamydial ClpX and ClpP2 orthologs are essential to organism viability and development. We demonstrate here that chlamydial ClpX is a functional ATPase and forms the expected homohexamer in vitro. Overexpression of a ClpX mutant lacking ATPase activity had a limited impact on DNA replication or secondary differentiation but, nonetheless, reduced EB viability with observable defects in EB morphology noted. Conversely, overexpression of a catalytically inactive ClpP2 mutant significantly impacted developmental cycle progression by reducing the overall number of organisms. Blocking clpP2X transcription using CRISPR interference led to a decrease in bacterial growth, and this effect was complemented in trans by a plasmid copy of clpP2. Taken together, our data indicate that ClpX and the associated ClpP2 serve distinct functions in chlamydial developmental cycle progression and differentiation.
Collapse
|
30
|
Torres-Delgado A, Kotamarthi HC, Sauer RT, Baker TA. The Intrinsically Disordered N-terminal Extension of the ClpS Adaptor Reprograms Its Partner AAA+ ClpAP Protease. J Mol Biol 2020; 432:4908-4921. [PMID: 32687854 DOI: 10.1016/j.jmb.2020.07.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 07/13/2020] [Accepted: 07/13/2020] [Indexed: 11/18/2022]
Abstract
Adaptor proteins modulate substrate selection by AAA+ proteases. The ClpS adaptor delivers N-degron substrates to ClpAP but inhibits degradation of substrates bearing ssrA tags or other related degrons. How ClpS inhibits degradation of such substrates is poorly understood. Here, we demonstrate that ClpS impedes recognition of ssrA-tagged substrates by a non-competitive mechanism and also slows subsequent unfolding/translocation of these substrates as well as of N-degron substrates. This suppression of mechanical activity is largely a consequence of the ability of ClpS to repress ATP hydrolysis by ClpA, but several lines of evidence show that ClpS's inhibition of substrate binding and its ATPase repression are separable activities. Using ClpS mutants and ClpS-ClpA chimeras, we establish that engagement of the intrinsically disordered N-terminal extension of ClpS by ClpA is both necessary and sufficient to inhibit multiple steps of ClpAP-catalyzed degradation. These observations reveal how an adaptor can simultaneously modulate the catalytic activity of a AAA+ enzyme, efficiently promote recognition of some substrates, suppress recognition of other substrates, and thereby affect degradation of its menu of substrates in a specific manner. We propose that similar mechanisms are likely to be used by other adaptors to regulate substrate choice and the catalytic activity of molecular machines.
Collapse
Affiliation(s)
- Amaris Torres-Delgado
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, 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.
| |
Collapse
|
31
|
Dittmar D, Reder A, Schlüter R, Riedel K, Hecker M, Gerth U. Complementation studies with human ClpP in Bacillus subtilis. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1867:118744. [PMID: 32442436 DOI: 10.1016/j.bbamcr.2020.118744] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 05/12/2020] [Accepted: 05/14/2020] [Indexed: 11/29/2022]
Abstract
ATP-dependent intracellular proteolysis is essential for all living organisms. ClpP, the proteolytic subunit of the ATP-dependent Clp proteases, shares 56% protein identity between B. subtilis and man. The aim of this study was to verify, whether human ClpP (HClpP) is able to substitute the bacterial pendant, BClpP, irrespectively of the huge evolutionary distance. For this reason hclpP was expressed from the natural B. subtilis promoters at the original chromosomal site. Growth at 37 °C as well as sporulation in the presence of hclpP depict an intermediate phenotype between wild type and clpP mutant suggesting a partial functional substitution of BClpP by HClpP. Northern as well as Western blot analyses show a similar induction pattern of both, bclpP and hclpP during heat stress on the mRNA as well as on the protein levels. Co-immunoprecipitation experiments imply specific interaction of HClpP with bacterial ClpC, ClpX and ClpE during control as well as heat stress conditions. Radioactive pulse-chase labeling and immunoprecipitation revealed that a ClpXP substrate, the short-living regulatory protein MgsR, is degraded by HClpP, although with an extremely slower rate in comparison to BClpP. The occurrence of an exceptional thickened cell wall of a clpP mutant can be almost fully reversed by the complementation with HClpP. The utilization of the HClpP expressing strain as a test system for new biological or synthetic active substances targeting BClpP is discussed.
Collapse
Affiliation(s)
- Denise Dittmar
- Institute of Microbiology of the Department of Biology, University of Greifswald, Germany; Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Alexander Reder
- Institute of Microbiology of the Department of Biology, University of Greifswald, Germany; Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Rabea Schlüter
- Imaging Center of the Department of Biology, University of Greifswald, Germany
| | - Katharina Riedel
- Institute of Microbiology of the Department of Biology, University of Greifswald, Germany
| | - Michael Hecker
- Institute of Microbiology of the Department of Biology, University of Greifswald, Germany
| | - Ulf Gerth
- Institute of Microbiology of the Department of Biology, University of Greifswald, Germany.
| |
Collapse
|
32
|
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.
Collapse
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.
| |
Collapse
|
33
|
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.
Collapse
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
| |
Collapse
|
34
|
Kardon JR, Moroco JA, Engen JR, Baker TA. Mitochondrial ClpX activates an essential biosynthetic enzyme through partial unfolding. eLife 2020; 9:54387. [PMID: 32091391 PMCID: PMC7077987 DOI: 10.7554/elife.54387] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 02/19/2020] [Indexed: 01/28/2023] Open
Abstract
Mitochondria control the activity, quality, and lifetime of their proteins with an autonomous system of chaperones, but the signals that direct substrate-chaperone interactions and outcomes are poorly understood. We previously discovered that the mitochondrial AAA+ protein unfoldase ClpX (mtClpX) activates the initiating enzyme for heme biosynthesis, 5-aminolevulinic acid synthase (ALAS), by promoting cofactor incorporation. Here, we ask how mtClpX accomplishes this activation. Using S. cerevisiae proteins, we identified sequence and structural features within ALAS that position mtClpX and provide it with a grip for acting on ALAS. Observation of ALAS undergoing remodeling by mtClpX revealed that unfolding is limited to a region extending from the mtClpX-binding site to the active site. Unfolding along this path is required for mtClpX to gate cofactor binding to ALAS. This targeted unfolding contrasts with the global unfolding canonically executed by ClpX homologs and provides insight into how substrate-chaperone interactions direct the outcome of remodeling.
Collapse
Affiliation(s)
- Julia R Kardon
- Department of Biochemistry, Brandeis University, Waltham, United States.,Department of Biology, Massachusetts Institute of Technology, Cambridge, United States.,Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, United States
| | - Jamie A Moroco
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, United States
| | - John R Engen
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, United States
| | - Tania A Baker
- Department of Biology, Massachusetts Institute of Technology, Cambridge, United States.,Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, United States
| |
Collapse
|
35
|
Gates SN, Martin A. Stairway to translocation: AAA+ motor structures reveal the mechanisms of ATP-dependent substrate translocation. Protein Sci 2020; 29:407-419. [PMID: 31599052 PMCID: PMC6954725 DOI: 10.1002/pro.3743] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Revised: 09/28/2019] [Accepted: 09/30/2019] [Indexed: 12/31/2022]
Abstract
Translocases of the AAA+ (ATPases Associated with various cellular Activities) family are powerful molecular machines that use the mechano-chemical coupling of ATP hydrolysis and conformational changes to thread DNA or protein substrates through their central channel for many important biological processes. These motors comprise hexameric rings of ATPase subunits, in which highly conserved nucleotide-binding domains form active-site pockets near the subunit interfaces and aromatic pore-loop residues extend into the central channel for substrate binding and mechanical pulling. Over the past 2 years, 41 cryo-EM structures have been solved for substrate-bound AAA+ translocases that revealed spiral-staircase arrangements of pore-loop residues surrounding substrate polypeptides and indicating a conserved hand-over-hand mechanism for translocation. The subunits' vertical positions within the spiral arrangements appear to be correlated with their nucleotide states, progressing from ATP-bound at the top to ADP or apo states at the bottom. Studies describing multiple conformations for a particular motor illustrate the potential coupling between ATP-hydrolysis steps and subunit movements to propel the substrate. Experiments with double-ring, Type II AAA+ motors revealed an offset of hydrolysis steps between the two ATPase domains of individual subunits, and the upper ATPase domains lacking aromatic pore loops frequently form planar rings. This review summarizes the critical advances provided by recent studies to our structural and functional understanding of hexameric AAA+ translocases, as well as the important outstanding questions regarding the underlying mechanisms for coordinated ATP-hydrolysis and mechano-chemical coupling.
Collapse
Affiliation(s)
- Stephanie N. Gates
- Department of Molecular and Cell BiologyUniversity of CaliforniaBerkeleyCalifornia
- California Institute for Quantitative BiosciencesUniversity of California at BerkeleyBerkeleyCalifornia
- Howard Hughes Medical InstituteUniversity of California at BerkeleyBerkeleyCalifornia
| | - Andreas Martin
- Department of Molecular and Cell BiologyUniversity of CaliforniaBerkeleyCalifornia
- California Institute for Quantitative BiosciencesUniversity of California at BerkeleyBerkeleyCalifornia
- Howard Hughes Medical InstituteUniversity of California at BerkeleyBerkeleyCalifornia
| |
Collapse
|
36
|
Ripstein ZA, Vahidi S, Houry WA, Rubinstein JL, Kay LE. A processive rotary mechanism couples substrate unfolding and proteolysis in the ClpXP degradation machinery. eLife 2020; 9:e52158. [PMID: 31916936 PMCID: PMC7112952 DOI: 10.7554/elife.52158] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 01/08/2020] [Indexed: 12/21/2022] Open
Abstract
The ClpXP degradation machine consists of a hexameric AAA+ unfoldase (ClpX) and a pair of heptameric serine protease rings (ClpP) that unfold, translocate, and subsequently degrade client proteins. ClpXP is an important target for drug development against infectious diseases. Although structures are available for isolated ClpX and ClpP rings, it remains unknown how symmetry mismatched ClpX and ClpP work in tandem for processive substrate translocation into the ClpP proteolytic chamber. Here, we present cryo-EM structures of the substrate-bound ClpXP complex from Neisseria meningitidis at 2.3 to 3.3 Å resolution. The structures allow development of a model in which the sequential hydrolysis of ATP is coupled to motions of ClpX loops that lead to directional substrate translocation and ClpX rotation relative to ClpP. Our data add to the growing body of evidence that AAA+ molecular machines generate translocating forces by a common mechanism.
Collapse
Affiliation(s)
- Zev A Ripstein
- Department of BiochemistryUniversity of TorontoTorontoCanada
- The Hospital for Sick Children Research InstituteTorontoCanada
| | - Siavash Vahidi
- Department of BiochemistryUniversity of TorontoTorontoCanada
- The Hospital for Sick Children Research InstituteTorontoCanada
- Department of Molecular GeneticsUniversity of TorontoTorontoCanada
- Department of ChemistryUniversity of TorontoTorontoCanada
| | - Walid A Houry
- Department of BiochemistryUniversity of TorontoTorontoCanada
- Department of ChemistryUniversity of TorontoTorontoCanada
| | - John L Rubinstein
- Department of BiochemistryUniversity of TorontoTorontoCanada
- The Hospital for Sick Children Research InstituteTorontoCanada
- Department of Medical BiophysicsUniversity of TorontoTorontoCanada
| | - Lewis E Kay
- Department of BiochemistryUniversity of TorontoTorontoCanada
- The Hospital for Sick Children Research InstituteTorontoCanada
- Department of Molecular GeneticsUniversity of TorontoTorontoCanada
- Department of ChemistryUniversity of TorontoTorontoCanada
| |
Collapse
|
37
|
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
| |
Collapse
|
38
|
Wong KS, Houry WA. Chemical Modulation of Human Mitochondrial ClpP: Potential Application in Cancer Therapeutics. ACS Chem Biol 2019; 14:2349-2360. [PMID: 31241890 DOI: 10.1021/acschembio.9b00347] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The human ClpP proteolytic complex (HsClpP) is a serine protease located in the mitochondrial matrix and participates in the maintenance of the mitochondrial proteome among other cellular functions. HsClpP typically forms a multimeric complex with the AAA+ protein unfoldase HsClpX. Notably, compared to that of normal, healthy cells, the expression of HsClpP in many types of solid and nonsolid cancers is found to be upregulated. While the exact role of HsClpP in tumorigenesis is not clear, certain types of cancers are highly dependent on the protease for cell proliferation and metastasis. In light of these observations, recent research has focused on the discovery and characterization of small organic molecules that can target and modulate HsClpP activity. These include compounds that inhibit HsClpP's proteolytic activity via covalent modification of its catalytic Ser residue as well as those that activate and dysregulate HsClpP by displacing HsClpX to negate its regulatory role. Importantly, several of these compounds have been shown to induce HsClpP-dependent apoptotic cell death in a variety of cancerous cells. This review provides an overview of these research efforts and highlights the various types of small molecule modulators of HsClpP activity with respect to their potential use as cancer therapeutics.
Collapse
Affiliation(s)
- Keith S. Wong
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5G 1M1, Canada
| | - Walid A. Houry
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5G 1M1, Canada
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| |
Collapse
|
39
|
Gatsogiannis C, Balogh D, Merino F, Sieber SA, Raunser S. Cryo-EM structure of the ClpXP protein degradation machinery. Nat Struct Mol Biol 2019; 26:946-954. [PMID: 31582852 PMCID: PMC6783313 DOI: 10.1038/s41594-019-0304-0] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 08/19/2019] [Indexed: 12/23/2022]
Abstract
The ClpXP machinery is a two component protease complex performing
targeted protein degradation in bacteria and mitochondria. The complex consists
of the AAA+ chaperone ClpX and the peptidase ClpP. The hexameric ClpX utilizes
the energy of ATP binding and hydrolysis to engage, unfold and translocate
substrates into the catalytic chamber of tetradecameric ClpP where they are
degraded. Formation of the complex involves a symmetry mismatch, since hexameric
AAA+ rings bind axially to the opposing stacked heptameric rings of the
tetradecameric ClpP. Here we present the cryo-EM structure of ClpXP from
Listeria monocytogenes. We unravel the heptamer-hexamer
binding interface and provide novel insights into the ClpX-ClpP crosstalk and
activation mechanism. The comparison with available crystal structures of ClpP
and ClpX in different states allows us to understand important aspects of
ClpXP’s complex mode of action and provides a structural framework for
future pharmacological applications.
Collapse
Affiliation(s)
- Christos Gatsogiannis
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Dora Balogh
- Department of Chemistry, Chair of Organic Chemistry II, Center for Integrated Protein Science (CIPSM), Technische Universität München, Garching, Germany
| | - Felipe Merino
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Stephan A Sieber
- Department of Chemistry, Chair of Organic Chemistry II, Center for Integrated Protein Science (CIPSM), Technische Universität München, Garching, Germany.
| | - Stefan Raunser
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany.
| |
Collapse
|
40
|
Rotanova TV, Andrianova AG, Kudzhaev AM, Li M, Botos I, Wlodawer A, Gustchina A. New insights into structural and functional relationships between LonA proteases and ClpB chaperones. FEBS Open Bio 2019; 9:1536-1551. [PMID: 31237118 PMCID: PMC6722904 DOI: 10.1002/2211-5463.12691] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 06/17/2019] [Accepted: 06/24/2019] [Indexed: 11/12/2022] Open
Abstract
LonA proteases and ClpB chaperones are key components of the protein quality control system in bacterial cells. LonA proteases form a unique family of ATPases associated with diverse cellular activities (AAA+ ) proteins due to the presence of an unusual N-terminal region comprised of two domains: a β-structured N domain and an α-helical domain, including the coiled-coil fragment, which is referred to as HI(CC). The arrangement of helices in the HI(CC) domain is reminiscent of the structure of the H1 domain of the first AAA+ module of ClpB chaperones. It has been hypothesized that LonA proteases with a single AAA+ module may also contain a part of another AAA+ module, the full version of which is present in ClpB. Here, we established and tested the structural basis of this hypothesis using the known crystal structures of various fragments of LonA proteases and ClpB chaperones, as well as the newly determined structure of the Escherichia coli LonA fragment (235-584). The similarities and differences in the corresponding domains of LonA proteases and ClpB chaperones were examined in structural terms. The results of our analysis, complemented by the finding of a singular match in the location of the most conserved axial pore-1 loop between the LonA NB domain and the NB2 domain of ClpB, support our hypothesis that there is a structural and functional relationship between two coiled-coil fragments and implies a similar mechanism of engagement of the pore-1 loops in the AAA+ modules of LonAs and ClpBs.
Collapse
Affiliation(s)
- Tatyana V. Rotanova
- Shemyakin‐Ovchinnikov Institute of Bioorganic ChemistryRussian Academy of SciencesMoscowRussia
| | - Anna G. Andrianova
- Shemyakin‐Ovchinnikov Institute of Bioorganic ChemistryRussian Academy of SciencesMoscowRussia
| | - Arsen M. Kudzhaev
- Shemyakin‐Ovchinnikov Institute of Bioorganic ChemistryRussian Academy of SciencesMoscowRussia
| | - Mi Li
- Protein Structure Section, Macromolecular Crystallography LaboratoryNational Cancer InstituteFrederickMDUSA
- Basic Science Program, Leidos Biomedical ResearchFrederick National Laboratory for Cancer ResearchFrederickMDUSA
| | - Istvan Botos
- Laboratory of Molecular BiologyNational Institute of Diabetes and Digestive and Kidney DiseasesBethesdaMDUSA
| | - Alexander Wlodawer
- Protein Structure Section, Macromolecular Crystallography LaboratoryNational Cancer InstituteFrederickMDUSA
| | - Alla Gustchina
- Protein Structure Section, Macromolecular Crystallography LaboratoryNational Cancer InstituteFrederickMDUSA
| |
Collapse
|
41
|
Steele TE, Glynn SE. Mitochondrial AAA proteases: A stairway to degradation. Mitochondrion 2019; 49:121-127. [PMID: 31377246 DOI: 10.1016/j.mito.2019.07.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 07/31/2019] [Indexed: 12/22/2022]
Abstract
Mitochondrial protein quality control requires the action of proteases to remove damaged or unnecessary proteins and perform key regulatory cleavage events. Important components of the quality control network are the mitochondrial AAA proteases, which capture energy from ATP hydrolysis to destabilize and degrade protein substrates on both sides of the inner membrane. Dysfunction of these proteases leads to the breakdown of mitochondrial proteostasis and is linked to the development of severe human diseases. In this review, we will describe recent insights into the structure and motions of the mitochondrial AAA proteases and related enzymes. Together, these studies have revealed the mechanics of ATP-driven protein destruction and significantly advanced our understanding of how these proteases maintain mitochondrial health.
Collapse
Affiliation(s)
- Tyler E Steele
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794, USA; Center for Structural Biology, Stony Brook University, Stony Brook, NY 11794, USA
| | - Steven E Glynn
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794, USA; Center for Structural Biology, Stony Brook University, Stony Brook, NY 11794, USA.
| |
Collapse
|
42
|
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.
Collapse
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;
| |
Collapse
|
43
|
Bell TA, Baker TA, Sauer RT. Interactions between a subset of substrate side chains and AAA+ motor pore loops determine grip during protein unfolding. eLife 2019; 8:46808. [PMID: 31251172 PMCID: PMC6677533 DOI: 10.7554/elife.46808] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 06/27/2019] [Indexed: 01/04/2023] Open
Abstract
Most AAA+ remodeling motors denature proteins by pulling on the peptide termini of folded substrates, but it is not well-understood how motors produce grip when resisting a folded domain. Here, at single amino-acid resolution, we identify the determinants of grip by measuring how substrate tail sequences alter the unfolding activity of the unfoldase-protease ClpXP. The seven amino acids abutting a stable substrate domain are key, with residues 2-6 forming a core that contributes most significantly to grip. ClpX grips large hydrophobic and aromatic side chains strongly and small, polar, or charged side chains weakly. Multiple side chains interact with pore loops synergistically to strengthen grip. In combination with recent structures, our results support a mechanism in which unfolding grip is primarily mediated by non-specific van der Waal's interactions between core side chains of the substrate tail and a subset of YVG loops at the top of the ClpX axial pore.
Collapse
Affiliation(s)
- Tristan A Bell
- Department of BiologyMassachusetts Institute of TechnologyCambridgeUnited States
| | - Tania A Baker
- Department of BiologyMassachusetts Institute of TechnologyCambridgeUnited States
- Howard Hughes Medical Institute, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Robert T Sauer
- Department of BiologyMassachusetts Institute of TechnologyCambridgeUnited States
| |
Collapse
|
44
|
Rizo AN, Lin J, Gates SN, Tse E, Bart SM, Castellano LM, DiMaio F, Shorter J, Southworth DR. Structural basis for substrate gripping and translocation by the ClpB AAA+ disaggregase. Nat Commun 2019; 10:2393. [PMID: 31160557 PMCID: PMC6546751 DOI: 10.1038/s41467-019-10150-y] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 04/24/2019] [Indexed: 01/04/2023] Open
Abstract
Bacterial ClpB and yeast Hsp104 are homologous Hsp100 protein disaggregases that serve critical functions in proteostasis by solubilizing protein aggregates. Two AAA+ nucleotide binding domains (NBDs) power polypeptide translocation through a central channel comprised of a hexameric spiral of protomers that contact substrate via conserved pore-loop interactions. Here we report cryo-EM structures of a hyperactive ClpB variant bound to the model substrate, casein in the presence of slowly hydrolysable ATPγS, which reveal the translocation mechanism. Distinct substrate-gripping interactions are identified for NBD1 and NBD2 pore loops. A trimer of N-terminal domains define a channel entrance that binds the polypeptide substrate adjacent to the topmost NBD1 contact. NBD conformations at the seam interface reveal how ATP hydrolysis-driven substrate disengagement and re-binding are precisely tuned to drive a directional, stepwise translocation cycle.
Collapse
Affiliation(s)
- Alexandrea N Rizo
- Graduate Program in Chemical Biology, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Biochemistry and Biophysics, Institute for Neurodegenerative Diseases, University of California, San Francisco, CA, 94158, USA
| | - JiaBei Lin
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Stephanie N Gates
- Graduate Program in Chemical Biology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Eric Tse
- Department of Biochemistry and Biophysics, Institute for Neurodegenerative Diseases, University of California, San Francisco, CA, 94158, USA
| | - Stephen M Bart
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Laura M Castellano
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Frank DiMaio
- Department of Biochemistry, University of Washington, Seattle, WA, 98195, USA
| | - James Shorter
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Daniel R Southworth
- Department of Biochemistry and Biophysics, Institute for Neurodegenerative Diseases, University of California, San Francisco, CA, 94158, USA.
| |
Collapse
|
45
|
Catipovic MA, Bauer BW, Loparo JJ, Rapoport TA. Protein translocation by the SecA ATPase occurs by a power-stroke mechanism. EMBO J 2019; 38:embj.2018101140. [PMID: 30877095 DOI: 10.15252/embj.2018101140] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 01/25/2019] [Accepted: 01/31/2019] [Indexed: 11/09/2022] Open
Abstract
SecA belongs to the large class of ATPases that use the energy of ATP hydrolysis to perform mechanical work resulting in protein translocation across membranes, protein degradation, and unfolding. SecA translocates polypeptides through the SecY membrane channel during protein secretion in bacteria, but how it achieves directed peptide movement is unclear. Here, we use single-molecule FRET to derive a model that couples ATP hydrolysis-dependent conformational changes of SecA with protein translocation. Upon ATP binding, the two-helix finger of SecA moves toward the SecY channel, pushing a segment of the polypeptide into the channel. The finger retracts during ATP hydrolysis, while the clamp domain of SecA tightens around the polypeptide, preserving progress of translocation. The clamp opens after phosphate release and allows passive sliding of the polypeptide chain through the SecA-SecY complex until the next ATP binding event. This power-stroke mechanism may be used by other ATPases that move polypeptides.
Collapse
Affiliation(s)
- Marco A Catipovic
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA.,Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, USA
| | - Benedikt W Bauer
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA.,Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, USA
| | - Joseph J Loparo
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Tom A Rapoport
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA .,Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, USA
| |
Collapse
|
46
|
Li L, Zheng J, Wu X, Jiang H. Mitochondrial AAA-ATPase Msp1 detects mislocalized tail-anchored proteins through a dual-recognition mechanism. EMBO Rep 2019; 20:embr.201846989. [PMID: 30858337 DOI: 10.15252/embr.201846989] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 01/28/2019] [Accepted: 02/11/2019] [Indexed: 01/09/2023] Open
Abstract
The conserved AAA-ATPase Msp1 is embedded in the outer mitochondrial membrane and removes mislocalized tail-anchored (TA) proteins upon dysfunction of the guided entry of tail-anchored (GET) pathway. It remains unclear how Msp1 recognizes its substrates. Here, we extensively characterize Msp1 and its substrates, including the mitochondrially targeted Pex15Δ30, and full-length Pex15, which mislocalizes to mitochondria upon dysfunction of Pex19 but not the GET pathway. Moreover, we identify two new substrates, Frt1 and Ysy6. Our results suggest that mislocalized TA proteins expose hydrophobic surfaces in the cytoplasm and are recognized by Msp1 through conserved hydrophobic residues. Introducing a hydrophobic patch into mitochondrial TA proteins transforms them into Msp1 substrates. In addition, Pex15Δ30 and Frt1 contain basic inter-membrane space (IMS) residues critical for their mitochondrial mistargeting. Remarkably, Msp1 recognizes this feature through the acidic D12 residue in its IMS domain. This dual-recognition mechanism involving interactions at the cytoplasmic and IMS domains of Msp1 and substrates greatly facilitates substrate recognition and is required by Msp1 to safeguard mitochondrial functions.
Collapse
Affiliation(s)
- Lanlan Li
- College of Life Sciences, Beijing Normal University, Beijing, China.,National Institute of Biological Sciences, Beijing, China.,Beijing Key Laboratory of Cell Biology for Animal Aging, Beijing, China
| | - Jing Zheng
- National Institute of Biological Sciences, Beijing, China.,Beijing Key Laboratory of Cell Biology for Animal Aging, Beijing, China.,School of Life Sciences, Peking University, Beijing, China
| | - Xi Wu
- National Institute of Biological Sciences, Beijing, China
| | - Hui Jiang
- National Institute of Biological Sciences, Beijing, China .,Beijing Key Laboratory of Cell Biology for Animal Aging, Beijing, China.,Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China
| |
Collapse
|
47
|
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
| |
Collapse
|
48
|
Initial Characterization of the Two ClpP Paralogs of Chlamydia trachomatis Suggests Unique Functionality for Each. J Bacteriol 2018; 201:JB.00635-18. [PMID: 30396899 DOI: 10.1128/jb.00635-18] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 10/24/2018] [Indexed: 12/28/2022] Open
Abstract
Members of Chlamydia are obligate intracellular bacteria that differentiate between two distinct functional and morphological forms during their developmental cycle, elementary bodies (EBs) and reticulate bodies (RBs). EBs are nondividing small electron-dense forms that infect host cells. RBs are larger noninfectious replicative forms that develop within a membrane-bound vesicle, termed an inclusion. Given the unique properties of each developmental form of this bacterium, we hypothesized that the Clp protease system plays an integral role in proteomic turnover by degrading specific proteins from one developmental form or the other. Chlamydia spp. have five uncharacterized clp genes, clpX, clpC, two clpP paralogs, and clpB In other bacteria, ClpC and ClpX are ATPases that unfold and feed proteins into the ClpP protease to be degraded, and ClpB is a deaggregase. Here, we focused on characterizing the ClpP paralogs. Transcriptional analyses and immunoblotting determined that these genes are expressed midcycle. Bioinformatic analyses of these proteins identified key residues important for activity. Overexpression of inactive clpP mutants in Chlamydia spp. suggested independent function of each ClpP paralog. To further probe these differences, we determined interactions between the ClpP proteins using bacterial two-hybrid assays and native gel analysis of recombinant proteins. Homotypic interactions of the ClpP proteins, but not heterotypic interactions between the ClpP paralogs, were detected. Interestingly, protease activity of ClpP2, but not ClpP1, was detected in vitro This activity was stimulated by antibiotics known to activate ClpP, which also blocked chlamydial growth. Our data suggest the chlamydial ClpP paralogs likely serve distinct and critical roles in this important pathogen.IMPORTANCE Chlamydia trachomatis is the leading cause of preventable infectious blindness and of bacterial sexually transmitted infections worldwide. Chlamydiae are developmentally regulated obligate intracellular pathogens that alternate between two functional and morphologic forms, with distinct repertoires of proteins. We hypothesize that protein degradation is a critical aspect to the developmental cycle. A key system involved in protein turnover in bacteria is the Clp protease system. Here, we characterized the two chlamydial ClpP paralogs by examining their expression in Chlamydia spp., their ability to oligomerize, and their proteolytic activity. This work will help understand the evolutionarily diverse Clp proteases in the context of intracellular organisms, which may aid in the study of other clinically relevant intracellular bacteria.
Collapse
|
49
|
Cotranslocational processing of the protein substrate calmodulin by an AAA+ unfoldase occurs via unfolding and refolding intermediates. Proc Natl Acad Sci U S A 2018; 115:E4786-E4795. [PMID: 29735657 DOI: 10.1073/pnas.1721811115] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Protein remodeling by AAA+ enzymes is central for maintaining proteostasis in a living cell. However, a detailed structural description of how this is accomplished at the level of the substrate molecules that are acted upon is lacking. Here, we combine chemical cross-linking and methyl transverse relaxation-optimized NMR spectroscopy to study, at atomic resolution, the stepwise unfolding and subsequent refolding of the two-domain substrate calmodulin by the VAT AAA+ unfoldase from Thermoplasma acidophilum By engineering intermolecular disulphide bridges between the substrate and VAT we trap the substrate at different stages of translocation, allowing structural studies throughout the translocation process. Our results show that VAT initiates substrate translocation by pulling on intrinsically unstructured N or C termini of substrate molecules without showing specificity for a particular amino acid sequence. Although the B1 domain of protein G is shown to unfold cooperatively, translocation of calmodulin leads to the formation of intermediates, and these differ on an individual domain level in a manner that depends on whether pulling is from the N or C terminus. The approach presented generates an atomic resolution picture of substrate unfolding and subsequent refolding by unfoldases that can be quite different from results obtained via in vitro denaturation experiments.
Collapse
|
50
|
Schwerter DP, Grimm I, Platta HW, Erdmann R. ATP-driven processes of peroxisomal matrix protein import. Biol Chem 2017; 398:607-624. [PMID: 27977397 DOI: 10.1515/hsz-2016-0293] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 12/11/2016] [Indexed: 12/13/2022]
Abstract
In peroxisomal matrix protein import two processes directly depend on the binding and hydrolysis of ATP, both taking place at the late steps of the peroxisomal import cycle. First, ATP hydrolysis is required to initiate a ubiquitin-transfer cascade to modify the import (co-)receptors. These receptors display a dual localization in the cytosol and at the peroxisomal membrane, whereas only the membrane bound fraction receives the ubiquitin modification. The second ATP-dependent process of the import cycle is carried out by the two AAA+-proteins Pex1p and Pex6p. These ATPases form a heterohexameric complex, which is recruited to the peroxisomal import machinery by the membrane anchor protein Pex15p. The Pex1p/Pex6p complex recognizes the ubiquitinated import receptors, pulls them out of the membrane and releases them into the cytosol. There the deubiquitinated receptors are provided for further rounds of import. ATP binding and hydrolysis are required for Pex1p/Pex6p complex formation and receptor export. In this review, we summarize the current knowledge on the peroxisomal import cascade. In particular, we will focus on the ATP-dependent processes, which are so far best understood in the model organism Saccharomyces cerevisiae.
Collapse
Affiliation(s)
- Daniel P Schwerter
- Abteilung für Systembiochemie, Institut für Biochemie und Pathobiochemie, Medizinische Fakultät der Ruhr-Universität Bochum, Universitätsstr. 150, D-44780 Bochum
| | - Immanuel Grimm
- Abteilung für Systembiochemie, Institut für Biochemie und Pathobiochemie, Medizinische Fakultät der Ruhr-Universität Bochum, Universitätsstr. 150, D-44780 Bochum
| | - Harald W Platta
- Biochemie Intrazellulärer Transportprozesse, Medizinische Fakultät der Ruhr-Universität Bochum, D-44780 Bochum
| | - Ralf Erdmann
- Abteilung für Systembiochemie, Institut für Biochemie und Pathobiochemie, Medizinische Fakultät der Ruhr-Universität Bochum, Universitätsstr. 150, D-44780 Bochum
| |
Collapse
|