1
|
Adaptation to simulated microgravity in Streptococcus mutans. NPJ Microgravity 2022; 8:17. [PMID: 35654802 PMCID: PMC9163064 DOI: 10.1038/s41526-022-00205-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 05/13/2022] [Indexed: 11/08/2022] Open
Abstract
Long-term space missions have shown an increased incidence of oral disease in astronauts’ and as a result, are one of the top conditions predicted to impact future missions. Here we set out to evaluate the adaptive response of Streptococcus mutans (etiological agent of dental caries) to simulated microgravity. This organism has been well studied on earth and treatment strategies are more predictable. Despite this, we are unsure how the bacterium will respond to the environmental stressors in space. We used experimental evolution for 100-days in high aspect ratio vessels followed by whole genome resequencing to evaluate this adaptive response. Our data shows that planktonic S. mutans did evolve variants in three genes (pknB, SMU_399 and SMU_1307c) that can be uniquely attributed to simulated microgravity populations. In addition, collection of data at multiple time points showed mutations in three additional genes (SMU_399, ptsH and rex) that were detected earlier in simulated microgravity populations than in the normal gravity controls, many of which are consistent with other studies. Comparison of virulence-related phenotypes between biological replicates from simulated microgravity and control orientation cultures generally showed few changes in antibiotic susceptibility, while acid tolerance and adhesion varied significantly between biological replicates and decreased as compared to the ancestral populations. Most importantly, our data shows the importance of a parallel normal gravity control, sequencing at multiple time points and the use of biological replicates for appropriate analysis of adaptation in simulated microgravity.
Collapse
|
2
|
Goda Pankaja Kumar, Sekhar T, Thriveni P, Venkateswarlu A, Peddanna K, Reddy PS, Krishna MH, Sreelatha T. Synthesis, Biological Evaluation, and Molecular Docking Studies of Some Spiro-5-Cyanopyrimidine Derivatives. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2021. [DOI: 10.1134/s1068162021060145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
3
|
King A, Blackledge MS. Evaluation of small molecule kinase inhibitors as novel antimicrobial and antibiofilm agents. Chem Biol Drug Des 2021; 98:1038-1064. [PMID: 34581492 PMCID: PMC8616828 DOI: 10.1111/cbdd.13962] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 08/24/2021] [Accepted: 09/15/2021] [Indexed: 12/25/2022]
Abstract
Antibiotic resistance is a global and pressing concern. Our current therapeutic arsenal is increasingly limited as bacteria are developing resistance at a rate that far outpaces our ability to create new treatments. Novel approaches to treating and curing bacterial infections are urgently needed. Bacterial kinases have been increasingly explored as novel drug targets and are poised for development into novel therapeutic agents to combat bacterial infections. This review describes several general classes of bacterial kinases that play important roles in bacterial growth, antibiotic resistance, and biofilm formation. General features of these kinase classes are discussed and areas of particular interest for the development of inhibitors will be highlighted. Small molecule kinase inhibitors are described and organized by phenotypic effect, spotlighting particularly interesting inhibitors with novel functions and potential therapeutic benefit. Finally, we provide our perspective on the future of bacterial kinase inhibition as a viable strategy to combat bacterial infections and overcome the pressures of increasing antibiotic resistance.
Collapse
Affiliation(s)
- Ashley King
- Department of Chemistry, High Point University, One University Parkway, High Point, NC 27268
| | - Meghan S. Blackledge
- Department of Chemistry, High Point University, One University Parkway, High Point, NC 27268
| |
Collapse
|
4
|
Wamp S, Rutter ZJ, Rismondo J, Jennings CE, Möller L, Lewis RJ, Halbedel S. PrkA controls peptidoglycan biosynthesis through the essential phosphorylation of ReoM. eLife 2020; 9:56048. [PMID: 32469310 PMCID: PMC7286690 DOI: 10.7554/elife.56048] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 05/27/2020] [Indexed: 12/15/2022] Open
Abstract
Peptidoglycan (PG) is the main component of bacterial cell walls and the target for many antibiotics. PG biosynthesis is tightly coordinated with cell wall growth and turnover, and many of these control activities depend upon PASTA-domain containing eukaryotic-like serine/threonine protein kinases (PASTA-eSTK) that sense PG fragments. However, only a few PG biosynthetic enzymes are direct kinase substrates. Here, we identify the conserved ReoM protein as a novel PASTA-eSTK substrate in the Gram-positive pathogen Listeria monocytogenes. Our data show that the phosphorylation of ReoM is essential as it controls ClpCP-dependent proteolytic degradation of the essential enzyme MurA, which catalyses the first committed step in PG biosynthesis. We also identify ReoY as a second novel factor required for degradation of ClpCP substrates. Collectively, our data imply that the first committed step of PG biosynthesis is activated through control of ClpCP protease activity in response to signals of PG homeostasis imbalance.
Collapse
Affiliation(s)
- Sabrina Wamp
- FG11 - Division of Enteropathogenic bacteria and Legionella, Robert Koch Institute, Wernigerode, Germany
| | - Zoe J Rutter
- Institute for Cell and Molecular Biosciences, Medical School, University of Newcastle, Newcastle upon Tyne, United Kingdom
| | - Jeanine Rismondo
- FG11 - Division of Enteropathogenic bacteria and Legionella, Robert Koch Institute, Wernigerode, Germany.,Department of General Microbiology, GZMB, Georg-August-Universität Göttingen, Göttingen, Germany
| | - Claire E Jennings
- Newcastle Drug Discovery, Northern Institute for Cancer Research, Newcastle upon Tyne, United Kingdom
| | - Lars Möller
- ZBS 4 - Advanced Light and Electron Microscopy, Robert Koch Institute, Berlin, Germany
| | - Richard J Lewis
- Institute for Cell and Molecular Biosciences, Medical School, University of Newcastle, Newcastle upon Tyne, United Kingdom
| | - Sven Halbedel
- FG11 - Division of Enteropathogenic bacteria and Legionella, Robert Koch Institute, Wernigerode, Germany
| |
Collapse
|
5
|
Cutrona N, Gillard K, Ulrich R, Seemann M, Miller HB, Blackledge MS. From Antihistamine to Anti-infective: Loratadine Inhibition of Regulatory PASTA Kinases in Staphylococci Reduces Biofilm Formation and Potentiates β-Lactam Antibiotics and Vancomycin in Resistant Strains of Staphylococcus aureus. ACS Infect Dis 2019; 5:1397-1410. [PMID: 31132246 DOI: 10.1021/acsinfecdis.9b00096] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Staphylococcus epidermidis and Staphylococcus aureus are important human pathogens responsible for two-thirds of all postsurgical infections of indwelling medical devices. Staphylococci form robust biofilms that provide a reservoir for chronic infection, and antibiotic-resistant isolates are increasingly common in both healthcare and community settings. Novel treatments that can simultaneously inhibit biofilm formation and antibiotic-resistance pathways are urgently needed to combat the increasing rates of antibiotic-resistant infections. Herein we report that loratadine, an FDA-approved antihistamine, significantly inhibits biofilm formation in both S. aureus and S. epidermidis. Furthermore, loratadine potentiates β-lactam antibiotics in methicillin-resistant strains of S. aureus and potentiates both β-lactam antibiotics and vancomycin in vancomycin-resistant strains of S. aureus. Additionally, we elucidate loratadine's mechanism of action as a novel inhibitor of the regulatory PASTA kinases Stk and Stk1 in S. epidermidis and S. aureus, respectively. Finally, we describe how Stk1 inhibition affects the expression of genes involved in both biofilm formation and antibiotic resistance in S. epidermidis and S. aureus.
Collapse
Affiliation(s)
- Nicholas Cutrona
- Department of Chemistry, High Point University, One University Parkway, High Point, North Carolina 27268, United States
| | - Kyra Gillard
- Department of Chemistry, High Point University, One University Parkway, High Point, North Carolina 27268, United States
| | - Rebecca Ulrich
- Department of Chemistry, High Point University, One University Parkway, High Point, North Carolina 27268, United States
| | - Mikaela Seemann
- Department of Chemistry, High Point University, One University Parkway, High Point, North Carolina 27268, United States
| | - Heather B. Miller
- Department of Chemistry, High Point University, One University Parkway, High Point, North Carolina 27268, United States
| | - Meghan S. Blackledge
- Department of Chemistry, High Point University, One University Parkway, High Point, North Carolina 27268, United States
| |
Collapse
|
6
|
Mori M, Sammartino JC, Costantino L, Gelain A, Meneghetti F, Villa S, Chiarelli LR. An Overview on the Potential Antimycobacterial Agents Targeting Serine/Threonine Protein Kinases from Mycobacterium tuberculosis. Curr Top Med Chem 2019; 19:646-661. [PMID: 30827246 DOI: 10.2174/1568026619666190227182701] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 09/27/2018] [Accepted: 10/09/2018] [Indexed: 01/07/2023]
Abstract
Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), still remains an urgent global health issue, mainly due to the emergence of multi-drug resistant strains. Therefore, there is a pressing need to develop novel and more efficient drugs to control the disease. In this context, targeting the pathogen virulence factors, and particularly signal mechanisms, seems to be a promising approach. An important transmembrane signaling system in Mtb is represented by receptor-type Serine/ Threonine protein kinases (STPKs). Mtb has 11 different STPKs, two of them, PknA and PknB, are essential. By contrast PknG and PknH are involved in Mtb virulence and adaptation, and are fundamental for the pathogen growth in infection models. Therefore, STPKs represent a very interesting group of pharmacological targets in M. tuberculosis. In this work, the principal inhibitors of the mycobacterial STPKs will be presented and discussed. In particular, medicinal chemistry efforts have been focused on discovering new antimycobacterial compounds, targeting three of these kinases, namely PknA, PknB and PknG. Generally, the inhibitory effect on these enzymes do not correlate with a significant antimycobacterial action in whole-cell assays. However, compounds with activity in the low micromolar range have been obtained, demonstrating that targeting Mtb STPKs could be a new promising strategy for the development of drugs to treat TB infections.
Collapse
Affiliation(s)
- Matteo Mori
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Milano, via L. Mangiagalli 25, 20133 Milano, Italy
| | - José Camilla Sammartino
- Dipartimento di Biologia e Biotecnologie "Lazzaro Spallanzani", Università degli Studi di Pavia, via Ferrata 9, 27100 Pavia, Italy
| | - Luca Costantino
- Dipartimento Scienze della Vita, Universita degli Studi di Modena e Reggio Emilia, via Campi 103, 41121 Modena, Italy
| | - Arianna Gelain
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Milano, via L. Mangiagalli 25, 20133 Milano, Italy
| | - Fiorella Meneghetti
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Milano, via L. Mangiagalli 25, 20133 Milano, Italy
| | - Stefania Villa
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Milano, via L. Mangiagalli 25, 20133 Milano, Italy
| | - Laurent Roberto Chiarelli
- Dipartimento di Biologia e Biotecnologie "Lazzaro Spallanzani", Università degli Studi di Pavia, via Ferrata 9, 27100 Pavia, Italy
| |
Collapse
|
7
|
Bellinzoni M, Wehenkel AM, Durán R, Alzari PM. Novel mechanistic insights into physiological signaling pathways mediated by mycobacterial Ser/Thr protein kinases. Microbes Infect 2019; 21:222-229. [PMID: 31254628 DOI: 10.1016/j.micinf.2019.06.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 04/02/2019] [Indexed: 12/11/2022]
Abstract
Protein phosphorylation is known to be one of the keystones of signal sensing and transduction in all living organisms. Once thought to be essentially confined to the eukaryotic kingdoms, reversible phosphorylation on serine, threonine and tyrosine residues, has now been shown to play a major role in many prokaryotes, where the number of Ser/Thr protein kinases (STPKs) equals or even exceeds that of two component systems. Mycobacterium tuberculosis, the etiological agent of tuberculosis, is one of the most studied organisms for the role of STPK-mediated signaling in bacteria. Driven by the interest and tractability of these enzymes as potential therapeutic targets, extensive studies revealed the remarkable conservation of protein kinases and their cognate phosphatases across evolution, and their involvement in bacterial physiology and virulence. Here, we present an overview of the current knowledge of mycobacterial STPKs structures and kinase activation mechanisms, and we then focus on PknB and PknG, two well-characterized STPKs that are essential for the intracellular survival of the bacillus. We summarize the mechanistic evidence that links PknB to the regulation of peptidoglycan synthesis in cell division and morphogenesis, and the major findings that establishes PknG as a master regulator of central carbon and nitrogen metabolism. Two decades after the discovery of STPKs in M. tuberculosis, the emerging landscape of O-phosphosignaling is starting to unveil how eukaryotic-like kinases can be engaged in unique, non-eukaryotic-like, signaling mechanisms in mycobacteria.
Collapse
Affiliation(s)
- Marco Bellinzoni
- Unit of Structural Microbiology, Department of Structural Biology and Chemistry, Institut Pasteur, CNRS UMR 3528 & Université Paris Diderot, 25 rue du Docteur Roux, 75724 Paris cedex 15, France
| | - Anne Marie Wehenkel
- Unit of Structural Microbiology, Department of Structural Biology and Chemistry, Institut Pasteur, CNRS UMR 3528 & Université Paris Diderot, 25 rue du Docteur Roux, 75724 Paris cedex 15, France
| | - Rosario Durán
- Unidad de Bioquímica y Proteómica Analíticas, Institut Pasteur de Montevideo, Instituto de Investigaciones Biológicas Clemente Estable, Mataojo 2020, Montevideo 11400, Uruguay
| | - Pedro M Alzari
- Unit of Structural Microbiology, Department of Structural Biology and Chemistry, Institut Pasteur, CNRS UMR 3528 & Université Paris Diderot, 25 rue du Docteur Roux, 75724 Paris cedex 15, France.
| |
Collapse
|
8
|
Labbe BD, Hall CL, Kellogg SL, Chen Y, Koehn O, Pickrum AM, Mirza SP, Kristich CJ. Reciprocal Regulation of PASTA Kinase Signaling by Differential Modification. J Bacteriol 2019; 201:e00016-19. [PMID: 30858297 PMCID: PMC6482931 DOI: 10.1128/jb.00016-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 03/01/2019] [Indexed: 12/20/2022] Open
Abstract
Transmembrane Ser/Thr kinases containing extracellular PASTA (penicillin-binding protein [PBP] and Ser/Thr-associated) domains are ubiquitous among Actinobacteria and Firmicutes species. Such PASTA kinases regulate critical bacterial processes, including antibiotic resistance, cell division, cell envelope homeostasis, and virulence, and are sometimes essential for viability. Previous studies of purified PASTA kinase fragments revealed they are capable of autophosphorylation in vitro, typically at multiple sites on the kinase domain. Autophosphorylation of a specific structural element of the kinase known as the activation loop is thought to enhance kinase activity in response to stimuli. However, the role of kinase phosphorylation at other sites is largely unknown. Moreover, the mechanisms by which PASTA kinases are deactivated once their stimulus has diminished are poorly understood. Enterococcus faecalis is a Gram-positive intestinal bacterium and a major antibiotic-resistant opportunistic pathogen. In E. faecalis, the PASTA kinase IreK drives intrinsic resistance to cell wall-active antimicrobials, and such antimicrobials trigger enhanced phosphorylation of IreK in vivo Here we identify multiple sites of phosphorylation on IreK and evaluate their function in vivo and in vitro While phosphorylation of the IreK activation loop is required for kinase activity, we found that phosphorylation at a site distinct from the activation loop reciprocally modulates IreK activity in vivo, leading to diminished activity (and diminished antimicrobial resistance). Moreover, this site is important for deactivation of IreK in vivo upon removal of an activating stimulus. Our results are consistent with a model in which phosphorylation of IreK at distinct sites reciprocally regulates IreK activity in vivo to promote adaptation to cell wall stresses.IMPORTANCE Transmembrane Ser/Thr kinases containing extracellular PASTA domains are ubiquitous among Actinobacteria and Firmicutes species and regulate critical processes, including antibiotic resistance, cell division, and cell envelope homeostasis. Previous studies of PASTA kinase fragments revealed autophosphorylation at multiple sites. However, the functional role of autophosphorylation and the relative impacts of phosphorylation at distinct sites are poorly understood. The PASTA kinase of Enterococcus faecalis, IreK, regulates intrinsic resistance to antimicrobials. Here we identify multiple sites of phosphorylation on IreK and show that modification of IreK at distinct sites reciprocally regulates IreK activity and antimicrobial resistance in vivo Thus, these results provide new insights into the mechanisms by which PASTA kinases can regulate critical physiological processes in a wide variety of bacterial species.
Collapse
Affiliation(s)
- Benjamin D Labbe
- Department of Microbiology and Immunology, Center for Infectious Disease Research, Medical College of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Cherisse L Hall
- Department of Microbiology and Immunology, Center for Infectious Disease Research, Medical College of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Stephanie L Kellogg
- Department of Microbiology and Immunology, Center for Infectious Disease Research, Medical College of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Yao Chen
- Department of Microbiology and Immunology, Center for Infectious Disease Research, Medical College of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Olivia Koehn
- Department of Microbiology and Immunology, Center for Infectious Disease Research, Medical College of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Adam M Pickrum
- Department of Microbiology and Immunology, Center for Infectious Disease Research, Medical College of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Shama P Mirza
- Department of Microbiology and Immunology, Center for Infectious Disease Research, Medical College of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Christopher J Kristich
- Department of Microbiology and Immunology, Center for Infectious Disease Research, Medical College of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| |
Collapse
|
9
|
Bellinzoni M, Wehenkel AM, Durán R, Alzari PM. Novel mechanistic insights into physiological signaling pathways mediated by mycobacterial Ser/Thr protein kinases. Genes Immun 2019; 20:383-393. [DOI: 10.1038/s41435-019-0069-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 04/02/2019] [Indexed: 12/16/2022]
|
10
|
Wlodarchak N, Teachout N, Beczkiewicz J, Procknow R, Schaenzer AJ, Satyshur K, Pavelka M, Zuercher W, Drewry D, Sauer JD, Striker R. In Silico Screen and Structural Analysis Identifies Bacterial Kinase Inhibitors which Act with β-Lactams To Inhibit Mycobacterial Growth. Mol Pharm 2018; 15:5410-5426. [PMID: 30285456 PMCID: PMC6648700 DOI: 10.1021/acs.molpharmaceut.8b00905] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
New tools and concepts are needed to combat antimicrobial resistance. Actinomycetes and firmicutes share several eukaryotic-like Ser/Thr kinases (eSTK) that offer antibiotic development opportunities, including PknB, an essential mycobacterial eSTK. Despite successful development of potent biochemical PknB inhibitors by many groups, clinically useful microbiologic activity has been elusive. Additionally, PknB kinetics are not fully described, nor are structures with specific inhibitors available to inform inhibitor design. We used computational modeling with available structural information to identify human kinase inhibitors predicted to bind PknB, and we selected hits based on drug-like characteristics intended to increase the likelihood of cell entry. The computational model suggested a family of inhibitors, the imidazopyridine aminofurazans (IPAs), bind PknB with high affinity. We performed an in-depth characterization of PknB and found that these inhibitors biochemically inhibit PknB, with potency roughly following the predicted models. A novel X-ray structure confirmed that the inhibitors bound as predicted and made favorable protein contacts with the target. These inhibitors also have antimicrobial activity toward mycobacteria and nocardia. We demonstrated that the inhibitors are uniquely potentiated by β-lactams but not antibiotics traditionally used to treat mycobacteria, consistent with PknB's role in sensing cell wall stress. This is the first demonstration in the phylum actinobacteria that some β-lactam antibiotics could be more effective if paired with a PknB inhibitor. Collectively, our data show that in silico modeling can be used as a tool to discover promising drug leads, and the inhibitors we discovered can act with clinically relevant antibiotics to restore their efficacy against bacteria with limited treatment options.
Collapse
Affiliation(s)
- Nathan Wlodarchak
- Department of Medicine, University of Wisconsin-Madison, 3341 Microbial Sciences Building, 1550 Linden Dr., Madison, WI 53706
| | - Nathan Teachout
- Department of Medicine, University of Wisconsin-Madison, 3341 Microbial Sciences Building, 1550 Linden Dr., Madison, WI 53706
| | - Jeffrey Beczkiewicz
- Department of Medicine, University of Wisconsin-Madison, 3341 Microbial Sciences Building, 1550 Linden Dr., Madison, WI 53706
| | - Rebecca Procknow
- Department of Medicine, University of Wisconsin-Madison, 3341 Microbial Sciences Building, 1550 Linden Dr., Madison, WI 53706
| | - Adam J. Schaenzer
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, 4203 Microbial Sciences Building, 1550 Linden Dr., Madison, WI 53706
| | - Kenneth Satyshur
- Small Molecule Screening Facility, Carbone Cancer Center, University of Wisconsin-Madison, 1111Highland Ave., Madison, WI 53705
| | - Martin Pavelka
- School of Medicine and Dentistry, University of Rochester Medical Center, 601 Elmwood Ave., Rochester, NY 14620
| | - William Zuercher
- Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, SGC Center for Chemical Biology, 120 Mason Farm Rd., Chapel Hill, NC 27599
| | - David Drewry
- Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, SGC Center for Chemical Biology, 120 Mason Farm Rd., Chapel Hill, NC 27599
| | - John-Demian Sauer
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, 4203 Microbial Sciences Building, 1550 Linden Dr., Madison, WI 53706
| | - Rob Striker
- Department of Medicine, University of Wisconsin-Madison, 3341 Microbial Sciences Building, 1550 Linden Dr., Madison, WI 53706,William S. Middleton Memorial Veterans Hospital, 2500 Overlook Terr., Madison, WI 53705,To whom correspondence should be addressed Rob Striker, Department of Medicine, University of Wisconsin-Madison, 3301 Microbial Sciences Building, 1550 Linden Dr., Madison, WI 53706, 608-263-2994,
| |
Collapse
|
11
|
The serine/threonine kinase Stk and the phosphatase Stp regulate cell wall synthesis in Staphylococcus aureus. Sci Rep 2018; 8:13693. [PMID: 30209409 PMCID: PMC6135852 DOI: 10.1038/s41598-018-32109-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 08/07/2018] [Indexed: 11/10/2022] Open
Abstract
The cell wall synthesis pathway producing peptidoglycan is a highly coordinated and tightly regulated process. Although the major components of bacterial cell walls have been known for decades, the complex regulatory network controlling peptidoglycan synthesis and many details of the cell division machinery are not well understood. The eukaryotic-like serine/threonine kinase Stk and the cognate phosphatase Stp play an important role in cell wall biosynthesis and drug resistance in S. aureus. We show that stp deletion has a pronounced impact on cell wall synthesis. Deletion of stp leads to a thicker cell wall and decreases susceptibility to lysostaphin. Stationary phase Δstp cells accumulate peptidoglycan precursors and incorporate higher amounts of incomplete muropeptides with non-glycine, monoglycine and monoalanine interpeptide bridges into the cell wall. In line with this cell wall phenotype, we demonstrate that the lipid II:glycine glycyltransferase FemX can be phosphorylated by the Ser/Thr kinase Stk in vitro. Mass spectrometric analyses identify Thr32, Thr36 and Ser415 as phosphoacceptors. The cognate phosphatase Stp dephosphorylates these phosphorylation sites. Moreover, Stk interacts with FemA and FemB, but is unable to phosphorylate them. Our data indicate that Stk and Stp modulate cell wall synthesis and cell division at several levels.
Collapse
|
12
|
Crystal structures of the kinase domain of PpkA, a key regulatory component of T6SS, reveal a general inhibitory mechanism. Biochem J 2018; 475:2209-2224. [DOI: 10.1042/bcj20180077] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 06/01/2018] [Accepted: 06/01/2018] [Indexed: 11/17/2022]
Abstract
The type VI secretion system (T6SS) is a versatile and widespread export system found in many Gram-negative bacteria that delivers effector proteins into target cells. The functions of T6SSs are tightly regulated by diverse mechanisms at multiple levels, including post-translational modification through threonine phosphorylation via the Ser/Thr protein kinase (STPK) PpkA. Here, we identified that PpkA is essential for T6SS secretion in Serratia marcescens since its deletion eliminated the secretion of haemolysin co-regulated protein, while the periplasmic and transmembrane portion of PpkA was found to be disposable for T6SS secretion. We further determined the crystal structure of the kinase domain of PpkA (PpkA-294). The structure of PpkA-294 was determined in its apo form to a 1.6 Å resolution as well as in complex with ATP to a 1.41 Å resolution and with an ATP analogue AMP-PCP to a 1.45 Å resolution. The residues in the activation loop of PpkA-294 were fully determined, and the N-terminus of the loop was folded into an unprecedented inhibitory helix, revealing that the PpkA kinase domain was in an auto-inhibitory state. The ternary MgATP–PpkA-294 complex was also inactive with nucleotide ribose and phosphates in unexpected and unproductive conformations. The αC-helix in the inactive PpkA-294 adopted a conformation towards the active site but with the conserved glutamate in the helix rotated away, which we suggest to be a general conformation for all STPK kinases in the inactive form. Structural comparison of PpkA with its eukaryotic homologues reinforced the universal regulation mechanism of protein kinases.
Collapse
|
13
|
Bruchhagen C, Jarick M, Mewis C, Hertlein T, Niemann S, Ohlsen K, Peters G, Planz O, Ludwig S, Ehrhardt C. Metabolic conversion of CI-1040 turns a cellular MEK-inhibitor into an antibacterial compound. Sci Rep 2018; 8:9114. [PMID: 29904167 PMCID: PMC6002397 DOI: 10.1038/s41598-018-27445-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 06/04/2018] [Indexed: 12/17/2022] Open
Abstract
Influenza virus (IV) infections cause severe respiratory illnesses that can be complicated by bacterial super-infections. Previously, we identified the cellular Raf-MEK-ERK cascade as a promising antiviral target. Inhibitors of MEK, such as CI-1040, showed potent antiviral activity. However, it remained unclear if this inhibitor and its active form, ATR-002, might sensitize host cells to either IV or secondary bacterial infections. To address these questions, we studied the anti-pathogen activity of ATR-002 in comparison to CI-1040, particularly, its impact on Staphylococcus aureus (S. aureus), which is a major cause of IV super-infections. We analysed IV and S. aureus titres in vitro during super-infection in the presence and absence of the drugs and characterized the direct impact of ATR-002 on bacterial growth and phenotypic changes. Importantly, neither CI-1040 nor ATR-002 treatment led to increased bacterial titres during super-infection, indicating that the drug does not sensitize cells for bacterial infection. In contrast, we rather observed reduced bacterial titres in presence of ATR-002. Surprisingly, ATR-002 also led to reduced bacterial growth in suspension cultures, reduced stress- and antibiotic tolerance without resistance induction. Our data identified for the first time that a particular MEK-inhibitor metabolite exhibits direct antibacterial activity, which is likely due to interference with the bacterial PknB kinase/Stp phosphatase signalling system.
Collapse
Affiliation(s)
- Christin Bruchhagen
- Institute of Virology Muenster (IVM), Westfaelische Wilhelms-University Muenster, Von-Esmarch-Str. 56, D-48149, Muenster, Germany
| | - Marcel Jarick
- Institute for Molecular Infection Biology (IMIB), University of Wuerzburg, Josef-Schneider-Str. 2/D15, D-97080, Wuerzburg, Germany
| | - Carolin Mewis
- Institute of Virology Muenster (IVM), Westfaelische Wilhelms-University Muenster, Von-Esmarch-Str. 56, D-48149, Muenster, Germany
| | - Tobias Hertlein
- Institute for Molecular Infection Biology (IMIB), University of Wuerzburg, Josef-Schneider-Str. 2/D15, D-97080, Wuerzburg, Germany
| | - Silke Niemann
- Institute of Medical Microbiology, University Hospital of Muenster, Domagkstr. 10, D-48149, Muenster, Germany
| | - Knut Ohlsen
- Institute for Molecular Infection Biology (IMIB), University of Wuerzburg, Josef-Schneider-Str. 2/D15, D-97080, Wuerzburg, Germany
| | - Georg Peters
- Institute of Medical Microbiology, University Hospital of Muenster, Domagkstr. 10, D-48149, Muenster, Germany
| | - Oliver Planz
- Interfaculty Institute for Cell Biology, Department of Immunology, University of Tuebingen, Auf der Morgenstelle 15, D-72076, Tuebingen, Germany
| | - Stephan Ludwig
- Institute of Virology Muenster (IVM), Westfaelische Wilhelms-University Muenster, Von-Esmarch-Str. 56, D-48149, Muenster, Germany
| | - Christina Ehrhardt
- Institute of Virology Muenster (IVM), Westfaelische Wilhelms-University Muenster, Von-Esmarch-Str. 56, D-48149, Muenster, Germany.
| |
Collapse
|
14
|
Zheng W, Cai X, Li S, Li Z. Autophosphorylation Mechanism of the Ser/Thr Kinase Stk1 From Staphylococcus aureus. Front Microbiol 2018; 9:758. [PMID: 29731745 PMCID: PMC5920020 DOI: 10.3389/fmicb.2018.00758] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 04/04/2018] [Indexed: 01/26/2023] Open
Abstract
The eukaryotic-like Ser/Thr kinase Stk1 is crucial for virulence, cell wall biosynthesis, and drug susceptibility in methicillin-resistant Staphylococcus aureus (S. aureus) (MRSA). Importantly, MRSA lacking Stk1 become sensitive to β-lactam antibiotics, implying that Stk1 could be an alternative target for combination therapy. However, the autophosphorylation mechanism of Stk1 remains elusive. Using a phosphoproteomic study, we identified six in vivo phosphorylated activation loop residues (Ser159, Thr161, Ser162, Thr164, Thr166, and Thr172) of Stk1, which are also phosphorylated in vitro. We further showed that cis autophosphorylation of Thr172 in the GT/S motif is essential for self-activation and kinase activity of Stk1 kinase domain (Stk1-KD), whereas the trans autophosphorylation of other activation loop serines/threonines are required for the optimal kinase activity of Stk1-KD. Moreover, substitution of the activation loop serines/threonines impaired in vivo autophosphorylation activity of kinase variants, while T172A and T172D variants were unable to autophosphorylate in the cellular content, underlining the essential role of Thr172 for Stk1 activity in vivo. This study provides insights into molecular basis for regulation of Stk1 activity from S. aureus.
Collapse
Affiliation(s)
- Weihao Zheng
- School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Xiaodan Cai
- School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Shuiming Li
- College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, China
| | - Zigang Li
- School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, China
| |
Collapse
|
15
|
Kant S, Asthana S, Missiakas D, Pancholi V. A novel STK1-targeted small-molecule as an "antibiotic resistance breaker" against multidrug-resistant Staphylococcus aureus. Sci Rep 2017; 7:5067. [PMID: 28698584 PMCID: PMC5505960 DOI: 10.1038/s41598-017-05314-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 06/15/2017] [Indexed: 01/28/2023] Open
Abstract
Ser/Thr protein kinase (STK1) plays a critical role in cell wall biosynthesis of and drug resistance in methicillin-resistant Staphylococcus aureus (MRSA). MRSA strains lacking STK1 become susceptible to failing cephalosporins, such as Ceftriaxone and Cefotaxime. STK1, despite being nonessential protein for MRSA survival, it can serve as an important therapeutic agent for combination therapy. Here, we report a novel small molecule quinazoline compound, Inh2-B1, which specifically inhibits STK1 activity by directly binding to its ATP-binding catalytic domain. Functional analyses encompassing in vitro growth inhibition of MRSA, and in vivo protection studies in mice against the lethal MRSA challenge indicated that at high concentration neither Inh2-B1 nor Ceftriaxone or Cefotaxime alone was able to inhibit the growth of bacteria or protect the challenged mice. However, the growth of MRSA was inhibited, and a significant protection in mice against the bacterial challenge was observed at a micromolar concentration of Ceftriaxone or Cefotaxime in the presence of Inh2-B1. Cell-dependent minimal to no toxicity of Inh2-B1, and its abilities to down-regulate cell wall hydrolase genes and disrupt the biofilm formation of MRSA clearly indicated that Inh2-B1 serves as a therapeutically important “antibiotic-resistance-breaker,” which enhances the bactericidal activity of Ceftriaxone/Cefotaxime against highly pathogenic MRSA infection.
Collapse
Affiliation(s)
- Sashi Kant
- Department of Pathology, The Ohio State University College of Medicine, Columbus, Ohio, USA
| | - Shailendra Asthana
- Drug Discovery Research Center, Translational Health Science and Technology Institute, Faridabad-Gurgaon Expressway, Haryana, India
| | | | - Vijay Pancholi
- Department of Pathology, The Ohio State University College of Medicine, Columbus, Ohio, USA.
| |
Collapse
|
16
|
Manuse S, Fleurie A, Zucchini L, Lesterlin C, Grangeasse C. Role of eukaryotic-like serine/threonine kinases in bacterial cell division and morphogenesis. FEMS Microbiol Rev 2015; 40:41-56. [DOI: 10.1093/femsre/fuv041] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/27/2015] [Indexed: 11/14/2022] Open
|
17
|
Wagner T, Alexandre M, Duran R, Barilone N, Wehenkel A, Alzari PM, Bellinzoni M. The crystal structure of the catalytic domain of the ser/thr kinase PknA from M. tuberculosis
shows an Src-like autoinhibited conformation. Proteins 2015; 83:982-8. [DOI: 10.1002/prot.24754] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 12/12/2014] [Accepted: 12/23/2014] [Indexed: 11/11/2022]
Affiliation(s)
- Tristan Wagner
- Institut Pasteur; Unité De Microbiologie Structurale; Paris 75724 France
- CNRS UMR 3528; Paris 75724 France
- Université Paris Diderot, Sorbonne Paris Cité; Microbiologie Structurale; Paris 75724 France
| | - Matthieu Alexandre
- Institut Pasteur; Unité De Microbiologie Structurale; Paris 75724 France
- CNRS UMR 3528; Paris 75724 France
- Université Paris Diderot, Sorbonne Paris Cité; Microbiologie Structurale; Paris 75724 France
| | - Rosario Duran
- Unidad De Bioquímica Y Proteómica Analíticas; Institut Pasteur De Montevideo; Uruguay
- Unidad De Bioquímica Y Proteómica Analíticas; Instituto De Investigaciones Biológicas Clemente Estable; Ministerio De Educación Y Cultura; Uruguay
| | - Nathalie Barilone
- Institut Pasteur; Unité De Microbiologie Structurale; Paris 75724 France
- CNRS UMR 3528; Paris 75724 France
- Université Paris Diderot, Sorbonne Paris Cité; Microbiologie Structurale; Paris 75724 France
| | - Annemarie Wehenkel
- Institut Pasteur; Unité De Microbiologie Structurale; Paris 75724 France
- CNRS UMR 3528; Paris 75724 France
- Université Paris Diderot, Sorbonne Paris Cité; Microbiologie Structurale; Paris 75724 France
| | - Pedro M. Alzari
- Institut Pasteur; Unité De Microbiologie Structurale; Paris 75724 France
- CNRS UMR 3528; Paris 75724 France
- Université Paris Diderot, Sorbonne Paris Cité; Microbiologie Structurale; Paris 75724 France
| | - Marco Bellinzoni
- Institut Pasteur; Unité De Microbiologie Structurale; Paris 75724 France
- CNRS UMR 3528; Paris 75724 France
- Université Paris Diderot, Sorbonne Paris Cité; Microbiologie Structurale; Paris 75724 France
| |
Collapse
|
18
|
Ravala SK, Singh S, Yadav GS, Kumar S, Karthikeyan S, Chakraborti PK. Evidence that phosphorylation of threonine in the GT motif triggers activation of PknA, a eukaryotic-type serine/threonine kinase from Mycobacterium tuberculosis. FEBS J 2015; 282:1419-31. [PMID: 25665034 DOI: 10.1111/febs.13230] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Revised: 01/21/2015] [Accepted: 01/28/2015] [Indexed: 12/31/2022]
Abstract
Phosphorylation of the activation loop in the catalytic domain of the RD family of bacterial eukaryotic-type Ser/Thr protein kinases (STPK) induces their conformational transition from an inactive to active state. However, mechanistic insights into the phosphorylation-mediated transition of these STPKs from an inactive to active state remain unknown. In the present study, we addressed this issue with PknA, an essential STPK from Mycobacterium tuberculosis. We found that the catalytic activity of PknA is confined within the N-terminal 283 amino acids (PknA-283). The crystal structure of PknA-283 in unphosphorylated form showed an ordered activation loop and existed in an inactive state preventing the phosphorylation of its cognate substrate(s). Peptide mass finger printing studies revealed that all activation loop threonines (Thr172, Thr174 and Thr180) were phosphorylated in the activated PknA-283 protein. Substitution of Thr180 with Ala/Asp (T180A/T180D) resulted in catalytically defective mutants, whereas a double mutant replacing Thr172 and Thr174 with Ala (T172A-T174A) was deficient in kinase activity. Analysis of PknA-283 structure, together with biochemical studies, revealed the possibility of phosphorylation of Thr180 via a cis mechanism, whereas that of Thr172 and Thr174 occurs via a trans mechanism. Moreover, unlike wild-type, these mutants did not show any drastic change in cell morphology in a phenotypic assay, implicating the role of all threonines in the activation loop towards the functionality of PknA. Thus, our findings offer a model for kinase activation showing that the phosphorylation of Thr180 triggers PknA to transphosphorylate Thr172/Thr174, thereby governing its functionality.
Collapse
|
19
|
Shi L, Pigeonneau N, Ravikumar V, Dobrinic P, Macek B, Franjevic D, Noirot-Gros MF, Mijakovic I. Cross-phosphorylation of bacterial serine/threonine and tyrosine protein kinases on key regulatory residues. Front Microbiol 2014; 5:495. [PMID: 25278935 PMCID: PMC4166321 DOI: 10.3389/fmicb.2014.00495] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 09/03/2014] [Indexed: 01/18/2023] Open
Abstract
Bacteria possess protein serine/threonine and tyrosine kinases which resemble eukaryal kinases in their capacity to phosphorylate multiple substrates. We hypothesized that the analogy might extend further, and bacterial kinases may also undergo mutual phosphorylation and activation, which is currently considered as a hallmark of eukaryal kinase networks. In order to test this hypothesis, we explored the capacity of all members of four different classes of serine/threonine and tyrosine kinases present in the firmicute model organism Bacillus subtilis to phosphorylate each other in vitro and interact with each other in vivo. The interactomics data suggested a high degree of connectivity among all types of kinases, while phosphorylation assays revealed equally wide-spread cross-phosphorylation events. Our findings suggest that the Hanks-type kinases PrkC, PrkD, and YabT exhibit the highest capacity to phosphorylate other B. subtilis kinases, while the BY-kinase PtkA and the two-component-like kinases RsbW and SpoIIAB show the highest propensity to be phosphorylated by other kinases. Analysis of phosphorylated residues on several selected recipient kinases suggests that most cross-phosphorylation events concern key regulatory residues. Therefore, cross-phosphorylation events are very likely to influence the capacity of recipient kinases to phosphorylate substrates downstream in the signal transduction cascade. We therefore conclude that bacterial serine/threonine and tyrosine kinases probably engage in a network-type behavior previously described only in eukaryal cells.
Collapse
Affiliation(s)
- Lei Shi
- SysBio, Department of Chemical and Biological Engineering, Chalmers University of Technology Göteborg, Sweden
| | - Nathalie Pigeonneau
- UMR1319 Micalis, Institut National de Recherche Agronomique Jouy-en-Josas, France
| | - Vaishnavi Ravikumar
- Proteome Center Tübingen, Interfaculty Institute for Cell Biology, University of Tübingen Tübingen, Germany
| | - Paula Dobrinic
- Division of Biology, Faculty of Science, Zagreb University Zagreb, Croatia
| | - Boris Macek
- Proteome Center Tübingen, Interfaculty Institute for Cell Biology, University of Tübingen Tübingen, Germany
| | - Damjan Franjevic
- Division of Biology, Faculty of Science, Zagreb University Zagreb, Croatia
| | | | - Ivan Mijakovic
- SysBio, Department of Chemical and Biological Engineering, Chalmers University of Technology Göteborg, Sweden
| |
Collapse
|
20
|
Kobayashi M, Kinjo T, Koseki Y, Bourne CR, Barrow WW, Aoki S. Identification of novel potential antibiotics against Staphylococcus using structure-based drug screening targeting dihydrofolate reductase. J Chem Inf Model 2014; 54:1242-53. [PMID: 24655350 PMCID: PMC4334291 DOI: 10.1021/ci400686d] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
![]()
The emergence of multidrug-resistant Staphylococcus aureus (S. aureus) makes
the treatment of infectious diseases
in hospitals more difficult and increases the mortality of the patients.
In this study, we attempted to identify novel potent antibiotic candidate
compounds against S. aureus dihydrofolate reductase
(saDHFR). We performed three-step in silico structure-based
drug screening (SBDS) based on the crystal structure of saDHFR using
a 154,118 chemical compound library. We subsequently evaluated whether
candidate chemical compounds exhibited inhibitory effects on the growth
of the model bacterium: Staphylococcus epidermidis (S. epidermidis). The compound KB1 showed a strong
inhibitory effect on the growth of S. epidermidis. Moreover, we rescreened chemical structures similar to KB1 from
a 461,397 chemical compound library. Three of the four KB1 analogs
(KBS1, KBS3, and KBS4) showed inhibitory effects on the growth of S. epidermidis and enzyme inhibitory effects on saDHFR.
We performed structure–activity relationship (SAR) analysis
of active chemical compounds and observed a correlative relationship
among the IC50 values, interaction residues, and structure
scaffolds. In addition, the active chemical compounds (KB1, KBS3,
and KBS4) had no inhibitory effects on the growth of model enterobacteria
(E. coli BL21 and JM109 strains) and no toxic effects
on cultured mammalian cells (MDCK cells). Results obtained from Protein
Ligand Interaction Fingerprint (PLIF) and Ligand Interaction (LI)
analyses suggested that all of the active compounds exhibited potential
inhibitory effects on mutated saDHFR of the drug-resistant strains.
The structural and experimental information concerning these novel
chemical compounds will likely contribute to the development of new
antibiotics for both wild-type and drug-resistant S. aureus.
Collapse
Affiliation(s)
- Maiko Kobayashi
- Department of Bioscience and Bioinformatics, Graduate School of Computer Science and Systems Engineering, Kyushu Institute of Technology , 680-4 Kawazu, Iizuka-shi, Fukuoka 820-8502, Japan
| | | | | | | | | | | |
Collapse
|
21
|
Ruggiero A, De Simone P, Smaldone G, Squeglia F, Berisio R. Bacterial cell division regulation by Ser/Thr kinases: a structural perspective. Curr Protein Pept Sci 2013; 13:756-66. [PMID: 23305362 PMCID: PMC3601408 DOI: 10.2174/138920312804871201] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Revised: 07/16/2012] [Accepted: 08/03/2012] [Indexed: 12/17/2022]
Abstract
Recent genetic, biochemical and structural studies have established that eukaryotic-like Ser/Thr protein-kinases are critical mediators of developmental changes and host pathogen interactions in bacteria. Although with lower abundance compared to their homologues from eukaryotes, Ser/Thr protein-kinases are widespread in gram-positive bacteria. These data underline a key role of reversible Ser/Thr phosphorylation in bacterial physiology and virulence. Numerous studies have revealed how phosphorylation/dephosphorylation of Ser/Thr protein-kinases governs cell division and cell wall biosynthesis and that Ser/Thr protein kinases are responsible for distinct phenotypes, dependent on different environmental signals. In this review we discuss the current understandings of Ser/Thr protein-kinases functional processes based on structural data.
Collapse
Affiliation(s)
- Alessia Ruggiero
- Institute of Biostructure and Bioimaging, CNR, Via Mezzocannone, 16. I-80134, Napoli, Italy.
| | | | | | | | | |
Collapse
|
22
|
Zinc regulates the activity of kinase-phosphatase pair (BasPrkC/BasPrpC) in Bacillus anthracis. Biometals 2013; 26:715-30. [PMID: 23793375 DOI: 10.1007/s10534-013-9646-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Accepted: 06/09/2013] [Indexed: 01/02/2023]
Abstract
Bacillus anthracis Ser/Thr protein kinase PrkC (BasPrkC) is important for virulence of the bacterium within the host. Homologs of PrkC and its cognate phosphatase PrpC (BasPrpC) are the most conserved mediators of signaling events in diverse bacteria. BasPrkC homolog in Bacillus subtilis regulates critical processes like spore germination and BasPrpC modulates the activity of BasPrkC by dephosphorylation. So far, biochemical and genetic studies have provided important insights into the roles of BasPrkC and BasPrpC; however, regulation of their activities is not known. We studied the regulation of BasPrkC/BasPrpC pair and observed that Zn(2+) metal ions can alter their activities. Zn(2+) promotes BasPrkC kinase activity while inhibits the BasPrpC phosphatase activity. Concentration of Zn(2+) in growing B. anthracis cells was found to vary with growth phase. Zn(2+) was found to be lowest in log phase cells while it was highest in spores. This variation in Zn(2+) concentration is significant for understanding the antagonistic activities of BasPrkC/BasPrpC pair. Our results also show that BasPrkC activity is modulated by temperature changes and kinase inhibitors. Additionally, we identified Elongation Factor Tu (BasEf-Tu) as a substrate of BasPrkC/BasPrpC pair and assessed the impact of their regulation on BasEf-Tu phosphorylation. Based on these results, we propose Zn(2+) as an important regulator of BasPrkC/BasPrpC mediated phosphorylation cascades. Thus, this study reveals additional means by which BasPrkC can be activated leading to autophosphorylation and substrate phosphorylation.
Collapse
|
23
|
Cousin C, Derouiche A, Shi L, Pagot Y, Poncet S, Mijakovic I. Protein-serine/threonine/tyrosine kinases in bacterial signaling and regulation. FEMS Microbiol Lett 2013; 346:11-9. [PMID: 23731382 DOI: 10.1111/1574-6968.12189] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 05/30/2013] [Accepted: 05/30/2013] [Indexed: 01/05/2023] Open
Abstract
In this review, we address some recent developments in the field of bacterial protein phosphorylation, focusing specifically on serine/threonine and tyrosine kinases. We present an overview of recent studies outlining the scope of physiological processes that are regulated by phosphorylation, ranging from cell cycle, growth, cell morphology, to metabolism, developmental phenomena, and virulence. Specific emphasis is placed on Mycobacterium tuberculosis as a showcase organism for serine/threonine kinases, and Bacillus subtilis to illustrate the importance of protein phosphorylation in developmental processes. We argue that bacterial serine/threonine and tyrosine kinases have a distinctive feature of phosphorylating multiple substrates and might thus represent integration nodes in the signaling network. Some open questions regarding the evolutionary benefits of relaxed substrate selectivity of these kinases are treated, as well as the notion of nonfunctional 'background' phosphorylation of cellular proteins. We also argue that phosphorylation events for which an immediate regulatory effect is not clearly established should not be dismissed as unimportant, as they may have a role in cross-talk with other post-translational modifications. Finally, recently developed methods for studying protein phosphorylation networks in bacteria are briefly discussed.
Collapse
|