1
|
Mawla GD, Kamal SM, Cao LY, Purhonen P, Hebert H, Sauer RT, Baker TA, Römling U. The membrane-cytoplasmic linker defines activity of FtsH proteases in Pseudomonas aeruginosa clone C. J Biol Chem 2024; 300:105622. [PMID: 38176647 PMCID: PMC10850787 DOI: 10.1016/j.jbc.2023.105622] [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: 08/12/2023] [Revised: 12/22/2023] [Accepted: 12/27/2023] [Indexed: 01/06/2024] Open
Abstract
Pandemic Pseudomonas aeruginosa clone C strains encode two inner-membrane associated ATP-dependent FtsH proteases. PaftsH1 is located on the core genome and supports cell growth and intrinsic antibiotic resistance, whereas PaftsH2, a xenolog acquired through horizontal gene transfer from a distantly related species, is unable to functionally replace PaftsH1. We show that purified PaFtsH2 degrades fewer substrates than PaFtsH1. Replacing the 31-amino acid-extended linker region of PaFtsH2 spanning from the C-terminal end of the transmembrane helix-2 to the first seven highly divergent residues of the cytosolic AAA+ ATPase module with the corresponding region of PaFtsH1 improves hybrid-enzyme substrate processing in vitro and enables PaFtsH2 to substitute for PaFtsH1 in vivo. Electron microscopy indicates that the identity of this linker sequence influences FtsH flexibility. We find membrane-cytoplasmic (MC) linker regions of PaFtsH1 characteristically glycine-rich compared to those from FtsH2. Consequently, introducing three glycines into the membrane-proximal end of PaFtsH2's MC linker is sufficient to elevate its activity in vitro and in vivo. Our findings establish that the efficiency of substrate processing by the two PaFtsH isoforms depends on MC linker identity and suggest that greater linker flexibility and/or length allows FtsH to degrade a wider spectrum of substrates. As PaFtsH2 homologs occur across bacterial phyla, we hypothesize that FtsH2 is a latent enzyme but may recognize specific substrates or is activated in specific contexts or biological niches. The identity of such linkers might thus play a more determinative role in the functionality of and physiological impact by FtsH proteases than previously thought.
Collapse
Affiliation(s)
- Gina D Mawla
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Shady M Kamal
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm; Sweden
| | - Lian-Ying Cao
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm; Sweden
| | - Pasi Purhonen
- Department of Biomedical Engineering and Health Systems, KTH Royal Institute of Technology, Huddinge; Sweden
| | - Hans Hebert
- Department of Biomedical Engineering and Health Systems, KTH Royal Institute of Technology, Huddinge; Sweden
| | - Robert T Sauer
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Tania A Baker
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.
| | - Ute Römling
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm; Sweden.
| |
Collapse
|
2
|
Programmed Proteolysis of Chemotaxis Proteins in Sinorhizobium meliloti: Features in the C-Terminal Region Control McpU Degradation. J Bacteriol 2020; 202:JB.00124-20. [PMID: 32571966 DOI: 10.1128/jb.00124-20] [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: 03/09/2020] [Accepted: 06/12/2020] [Indexed: 11/20/2022] Open
Abstract
Chemotaxis and motility are important traits that support bacterial survival in various ecological niches and in pathogenic and symbiotic host interaction. Chemotactic stimuli are sensed by chemoreceptors or methyl-accepting chemotaxis proteins (MCPs), which direct the swimming behavior of the bacterial cell. In this study, we present evidence that the cellular abundance of chemoreceptors in the plant symbiont Sinorhizobium meliloti can be altered by the addition of several to as few as one amino acid residues and by including common epitope tags such as 3×FLAG and 6×His at their C termini. To further dissect this phenomenon and its underlying molecular mechanism, we focused on a detailed analysis of the amino acid sensor McpU. Controlled proteolysis is important for the maintenance of an appropriate stoichiometry of chemoreceptors and between chemoreceptors and chemotactic signaling proteins, which is essential for an optimal chemotactic response. We hypothesized that enhanced stability is due to interference with protease binding, thus affecting proteolytic efficacy. Location of the protease recognition site was defined through McpU stability measurements in a series of deletion and amino acid substitution mutants. Deletions in the putative protease recognition site had similar effects on McpU abundance, as did extensions at the C terminus. Our results provide evidence that the programmed proteolysis of chemotaxis proteins in S. meliloti is cell cycle regulated. This posttranslational control, together with regulatory pathways on the transcriptional level, limits the chemotaxis machinery to the early exponential growth phase. Our study identified parallels to cell cycle-dependent processes during asymmetric cell division in Caulobacter crescentus IMPORTANCE The symbiotic bacterium Sinorhizobium meliloti contributes greatly to growth of the agriculturally valuable host plant alfalfa by fixing atmospheric nitrogen. Chemotaxis of S. meliloti cells toward alfalfa roots mediates this symbiosis. The present study establishes programmed proteolysis as a factor in the maintenance of the S. meliloti chemotaxis system. Knowledge about cell cycle-dependent, targeted, and selective proteolysis in S. meliloti is important to understand the molecular mechanisms of maintaining a suitable chemotaxis response. While the role of regulated protein turnover in the cell cycle progression of Caulobacter crescentus is well understood, these pathways are just beginning to be characterized in S. meliloti In addition, our study should alert about the cautionary use of epitope tags for protein quantification.
Collapse
|
3
|
Baytshtok V, Chen J, Glynn SE, Nager AR, Grant RA, Baker TA, Sauer RT. Covalently linked HslU hexamers support a probabilistic mechanism that links ATP hydrolysis to protein unfolding and translocation. J Biol Chem 2017; 292:5695-5704. [PMID: 28223361 DOI: 10.1074/jbc.m116.768978] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 02/07/2017] [Indexed: 11/06/2022] Open
Abstract
The HslUV proteolytic machine consists of HslV, a double-ring self-compartmentalized peptidase, and one or two AAA+ HslU ring hexamers that hydrolyze ATP to power the unfolding of protein substrates and their translocation into the proteolytic chamber of HslV. Here, we use genetic tethering and disulfide bonding strategies to construct HslU pseudohexamers containing mixtures of ATPase active and inactive subunits at defined positions in the hexameric ring. Genetic tethering impairs HslV binding and degradation, even for pseudohexamers with six active subunits, but disulfide-linked pseudohexamers do not have these defects, indicating that the peptide tether interferes with HslV interactions. Importantly, pseudohexamers containing different patterns of hydrolytically active and inactive subunits retain the ability to unfold protein substrates and/or collaborate with HslV in their degradation, supporting a model in which ATP hydrolysis and linked mechanical function in the HslU ring operate by a probabilistic mechanism.
Collapse
Affiliation(s)
| | | | | | | | | | - Tania A Baker
- From the Department of Biology and.,Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | | |
Collapse
|
4
|
Bittner LM, Arends J, Narberhaus F. Mini review: ATP-dependent proteases in bacteria. Biopolymers 2017; 105:505-17. [PMID: 26971705 DOI: 10.1002/bip.22831] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 02/11/2016] [Accepted: 03/07/2016] [Indexed: 01/22/2023]
Abstract
AAA(+) proteases are universal barrel-like and ATP-fueled machines preventing the accumulation of aberrant proteins and regulating the proteome according to the cellular demand. They are characterized by two separate operating units, the ATPase and peptidase domains. ATP-dependent unfolding and translocation of a substrate into the proteolytic chamber is followed by ATP-independent degradation. This review addresses the structure and function of bacterial AAA(+) proteases with a focus on the ATP-driven mechanisms and the coordinated movements in the complex mainly based on the knowledge of ClpXP. We conclude by discussing strategies how novel protease substrates can be trapped by mutated AAA(+) protease variants. © 2016 Wiley Periodicals, Inc. Biopolymers 105: 505-517, 2016.
Collapse
Affiliation(s)
| | - Jan Arends
- Microbial Biology, Ruhr University Bochum, Bochum, Germany
| | | |
Collapse
|
5
|
Baytshtok V, Fei X, Grant RA, Baker TA, Sauer RT. A Structurally Dynamic Region of the HslU Intermediate Domain Controls Protein Degradation and ATP Hydrolysis. Structure 2016; 24:1766-1777. [PMID: 27667691 DOI: 10.1016/j.str.2016.08.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 08/02/2016] [Accepted: 08/06/2016] [Indexed: 11/30/2022]
Abstract
The I domain of HslU sits above the AAA+ ring and forms a funnel-like entry to the axial pore, where protein substrates are engaged, unfolded, and translocated into HslV for degradation. The L199Q I-domain substitution, which was originally reported as a loss-of-function mutation, resides in a segment that appears to adopt multiple conformations as electron density is not observed in HslU and HslUV crystal structures. The L199Q sequence change does not alter the structure of the AAA+ ring or its interactions with HslV but increases I-domain susceptibility to limited endoproteolysis. Notably, the L199Q mutation increases the rate of ATP hydrolysis substantially, results in slower degradation of some proteins but faster degradation of other substrates, and markedly changes the preference of HslUV for initiating degradation at the N or C terminus of model substrates. Thus, a structurally dynamic region of the I domain plays a key role in controlling protein degradation by HslUV.
Collapse
Affiliation(s)
- Vladimir Baytshtok
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Xue Fei
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Robert A Grant
- 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; Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Robert T Sauer
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
| |
Collapse
|
6
|
Alcántara C, Zúñiga M. Proteomic and transcriptomic analysis of the response to bile stress of Lactobacillus casei BL23. Microbiology (Reading) 2012; 158:1206-1218. [DOI: 10.1099/mic.0.055657-0] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Affiliation(s)
- Cristina Alcántara
- Departamento de Biotecnología de Alimentos, Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC) PO Box 73, 46100 Burjassot, Valencia, Spain
| | - Manuel Zúñiga
- Departamento de Biotecnología de Alimentos, Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC) PO Box 73, 46100 Burjassot, Valencia, Spain
| |
Collapse
|
7
|
Sundar S, Baker TA, Sauer RT. The I domain of the AAA+ HslUV protease coordinates substrate binding, ATP hydrolysis, and protein degradation. Protein Sci 2012; 21:188-98. [PMID: 22102327 DOI: 10.1002/pro.2001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Revised: 11/09/2011] [Accepted: 11/10/2011] [Indexed: 11/11/2022]
Abstract
In the AAA+ HslUV protease, substrates are bound and unfolded by a ring hexamer of HslU, before translocation through an axial pore and into the HslV degradation chamber. Here, we show that the N-terminal residues of an Arc substrate initially bind in the HslU axial pore, with key contacts mediated by a pore loop that is highly conserved in all AAA+ unfoldases. Disordered loops from the six intermediate domains of the HslU hexamer project into a funnel-shaped cavity above the pore and are positioned to contact protein substrates. Mutations in these I-domain loops increase K(M) and decrease V(max) for degradation, increase the mobility of bound substrates, and prevent substrate stimulation of ATP hydrolysis. HslU-ΔI has negligible ATPase activity. Thus, the I domain plays an active role in coordinating substrate binding, ATP hydrolysis, and protein degradation by the HslUV proteolytic machine.
Collapse
Affiliation(s)
- Shankar Sundar
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | | | | |
Collapse
|
8
|
Stepwise activity of ClpY (HslU) mutants in the processive degradation of Escherichia coli ClpYQ (HslUV) protease substrates. J Bacteriol 2011; 193:5465-76. [PMID: 21803990 DOI: 10.1128/jb.05128-11] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In Escherichia coli, ClpYQ (HslUV) is a two-component ATP-dependent protease composed of ClpY (HslU), an ATPase with unfolding activity, and ClpQ (HslV), a peptidase. In the ClpYQ proteolytic complex, the hexameric rings of ClpY (HslU) are responsible for protein recognition, unfolding, and translocation into the proteolytic inner chamber of the dodecameric ClpQ (HslV). Each of the three domains, N, I, and C, in ClpY has its own distinct activity. The double loops (amino acids [aa] 137 to 150 and 175 to 209) in domain I of ClpY are necessary for initial recognition/tethering of natural substrates such as SulA, a cell division inhibitor protein. The highly conserved sequence GYVG (aa 90 to 93) pore I site, along with the GESSG pore II site (aa 265 to 269), contribute to the central pore of ClpY in domain N. These two central loops of ClpY are in the center of its hexameric ring in which the energy of ATP hydrolysis allows substrate translocation and then degradation by ClpQ. However, no data have been obtained to determine the effect of the central loops on substrate binding or as part of the processivity of the ClpYQ complex. Thus, we probed the features of ClpY important for substrate engagement and protease processivity via random PCR or site-specific mutagenesis. In yeast two-hybrid analysis and pulldown assays, using isolated ClpY mutants and the pore I or pore II site of ClpY, each was examined for its influence on the adjoining structural regions of the substrates. The pore I site is essential for the translocation of the engaged substrates. Our in vivo study of the ClpY mutants also revealed that an ATP-binding site in domain N, separate from its role in polypeptide (ClpY) oligomerization, is required for complex formation with ClpQ. Additionally, we found that the tyrosine residue at position 408 in ClpY is critical for stabilization of hexamer formation between subunits. Therefore, our studies suggest that stepwise activities of the ClpYQ protease are necessary to facilitate the processive degradation of its natural substrates.
Collapse
|
9
|
Richter K, Haslbeck M, Buchner J. The heat shock response: life on the verge of death. Mol Cell 2010; 40:253-66. [PMID: 20965420 DOI: 10.1016/j.molcel.2010.10.006] [Citation(s) in RCA: 1262] [Impact Index Per Article: 90.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 10/03/2010] [Accepted: 10/05/2010] [Indexed: 12/16/2022]
Abstract
Organisms must survive a variety of stressful conditions, including sudden temperature increases that damage important cellular structures and interfere with essential functions. In response to heat stress, cells activate an ancient signaling pathway leading to the transient expression of heat shock or heat stress proteins (Hsps). Hsps exhibit sophisticated protection mechanisms, and the most conserved Hsps are molecular chaperones that prevent the formation of nonspecific protein aggregates and assist proteins in the acquisition of their native structures. In this Review, we summarize the concepts of the protective Hsp network.
Collapse
Affiliation(s)
- Klaus Richter
- Munich Center for Integrated Protein Science, Department Chemie Technische Universität München, 85747 Garching, Germany
| | | | | |
Collapse
|