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Noel HR, Keerthi S, Ren X, Winkelman JD, Troutman JM, Palmer LD. Genetic synergy between Acinetobacter baumannii undecaprenyl phosphate biosynthesis and the Mla system impacts cell envelope and antimicrobial resistance. mBio 2024; 15:e0280423. [PMID: 38364179 PMCID: PMC10936186 DOI: 10.1128/mbio.02804-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 01/17/2024] [Indexed: 02/18/2024] Open
Abstract
Acinetobacter baumannii is a Gram-negative bacterial pathogen that poses a major health concern due to increasing multidrug resistance. The Gram-negative cell envelope is a key barrier to antimicrobial entry and includes an inner and outer membrane. The maintenance of lipid asymmetry (Mla) system is the main homeostatic mechanism by which Gram-negative bacteria maintain outer membrane asymmetry. Loss of the Mla system in A. baumannii results in attenuated virulence and increased susceptibility to membrane stressors and some antibiotics. We recently reported two strain variants of the A. baumannii type strain ATCC 17978: 17978VU and 17978UN. Here, ∆mlaF mutants in the two ATCC 17978 strains display different phenotypes for membrane stress resistance, antibiotic resistance, and pathogenicity in a murine pneumonia model. Although allele differences in obgE were previously reported to synergize with ∆mlaF to affect growth and stringent response, obgE alleles do not affect membrane stress resistance. Instead, a single-nucleotide polymorphism (SNP) in the essential gene encoding undecaprenyl pyrophosphate (Und-PP) synthase, uppS, results in decreased enzymatic rate and decrease in total Und-P levels in 17978UN compared to 17978VU. The UppSUN variant synergizes with ∆mlaF to reduce capsule and lipooligosaccharide (LOS) levels, increase susceptibility to membrane stress and antibiotics, and reduce persistence in a mouse lung infection. Und-P is a lipid glycan carrier required for the biosynthesis of A. baumannii capsule, cell wall, and glycoproteins. These findings uncover synergy between Und-P and the Mla system in maintaining the A. baumannii cell envelope and antibiotic resistance.IMPORTANCEAcinetobacter baumannii is a critical threat to global public health due to its multidrug resistance and persistence in hospital settings. Therefore, novel therapeutic approaches are urgently needed. We report that a defective undecaprenyl pyrophosphate synthase (UppS) paired with a perturbed Mla system leads to synthetically sick cells that are more susceptible to clinically relevant antibiotics and show reduced virulence in a lung infection model. These results suggest that targeting UppS or undecaprenyl species and the Mla system may resensitize A. baumannii to antibiotics in combination therapies. This work uncovers a previously unknown synergistic relationship in cellular envelope homeostasis that could be leveraged for use in combination therapy against A. baumannii.
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Affiliation(s)
- Hannah R. Noel
- Department of Microbiology and Immunology, University of Illinois Chicago, Chicago, Illinois, USA
| | - Sowmya Keerthi
- Department of Chemistry, University of North Carolina Charlotte, Charlotte, North Carolina, USA
| | - Xiaomei Ren
- Department of Microbiology and Immunology, University of Illinois Chicago, Chicago, Illinois, USA
| | | | - Jerry M. Troutman
- Department of Chemistry, University of North Carolina Charlotte, Charlotte, North Carolina, USA
| | - Lauren D. Palmer
- Department of Microbiology and Immunology, University of Illinois Chicago, Chicago, Illinois, USA
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2
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Suarez C, Winkelman JD, Harker AJ, Ye HJ, McCall PM, Morganthaler AN, Gardel ML, Kovar DR. Reconstitution of the transition from a lamellipodia- to filopodia-like actin network with purified proteins. Eur J Cell Biol 2023; 102:151367. [PMID: 37890285 DOI: 10.1016/j.ejcb.2023.151367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 09/29/2023] [Accepted: 10/19/2023] [Indexed: 10/29/2023] Open
Abstract
How cells utilize complex mixtures of actin binding proteins to assemble and maintain functionally diverse actin filament networks with distinct architectures and dynamics within a common cytoplasm is a longstanding question in cell biology. A compelling example of complex and specialized actin structures in cells are filopodia which sense extracellular chemical and mechanical signals to help steer motile cells. Filopodia have distinct actin architecture, composed of long, parallel actin filaments bundled by fascin, which form finger-like membrane protrusions. Elongation of the parallel actin filaments in filopodia can be mediated by two processive actin filament elongation factors, formin and Ena/VASP, which localize to the tips of filopodia. There remains debate as to how the architecture of filopodia are generated, with one hypothesis proposing that filopodia are generated from the lamellipodia, which consists of densely packed, branched actin filaments nucleated by Arp2/3 complex and kept short by capping protein. It remains unclear if different actin filament elongation factors are necessary and sufficient to facilitate the emergence of filopodia with diverse characteristics from a highly dense network of short-branched capped filaments. To address this question, we combined bead motility and micropatterning biomimetic assays with multi-color Total Internal Reflection Fluorescence microscopy imaging, to successfully reconstitute the formation of filopodia-like networks (FLN) from densely-branched lamellipodia-like networks (LLN) with eight purified proteins (actin, profilin, Arp2/3 complex, Wasp pWA, fascin, capping protein, VASP and formin mDia2). Saturating capping protein concentrations inhibit FLN assembly, but the addition of either formin or Ena/VASP differentially rescues the formation of FLN from LLN. Specifically, we found that formin/mDia2-generated FLNs are relatively long and lack capping protein, whereas VASP-generated FLNs are comparatively short and contain capping protein, indicating that the actin elongation factor can affect the architecture and composition of FLN emerging from LLN. Our biomimetic reconstitution systems reveal that formin or VASP are necessary and sufficient to induce the transition from a LLN to a FLN, and establish robust in vitro platforms to investigate FLN assembly mechanisms.
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Affiliation(s)
- Cristian Suarez
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA.
| | - Jonathan D Winkelman
- Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
| | - Alyssa J Harker
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Hannah J Ye
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Patrick M McCall
- Department of Physics, The University of Chicago, Chicago, IL 60637, USA; James Franck Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Alisha N Morganthaler
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Margaret L Gardel
- Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA; Department of Physics, The University of Chicago, Chicago, IL 60637, USA; James Franck Institute, The University of Chicago, Chicago, IL 60637, USA; Pritzker School for Molecular Engineering, The University of Chicago, Chicago, IL 60637, USA
| | - David R Kovar
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA; Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA.
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3
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Noel HR, Keerthi S, Ren X, Winkelman JD, Troutman JM, Palmer LD. Genetic synergy in Acinetobacter baumannii undecaprenyl biosynthesis and maintenance of lipid asymmetry impacts outer membrane and antimicrobial resistance. bioRxiv 2023:2023.09.22.556980. [PMID: 37790371 PMCID: PMC10542541 DOI: 10.1101/2023.09.22.556980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Acinetobacter baumannii is a Gram-negative healthcare-associated pathogen that poses a major health concern due to increasing multidrug resistance. The Gram-negative cell envelope is a key barrier to antimicrobial entry and includes an inner and outer membrane. The outer membrane has an asymmetric composition that is important for structural integrity and barrier to the environment. Therefore, Gram-negative bacteria have mechanisms to uphold this asymmetry such as the maintenance of lipid asymmetry system (Mla), which removes glycerophospholipids from the outer leaflet of the outer membrane and transports them to the inner membrane. Loss of this system in A. baumannii results in attenuated virulence and increased susceptibility to membrane stressors and some antibiotics. We recently reported two strain variants of the A. baumannii type strain ATCC 17978, 17978VU and 17978UN. We show here that ΔmlaF mutants in the two strains display different phenotypes for membrane stress resistance, antibiotic resistance, and pathogenicity in a murine pneumonia model. We used comparative genetics to identify interactions between ATCC 17978 strain alleles and mlaF to uncover the cause behind the phenotypic differences. Although allele differences in obgE were previously reported to synergize with ΔmlaF to affect growth and stringent response, we show that obgE alleles do not affect membrane stress resistance. Instead, a single nucleotide polymorphism (SNP) in the essential gene encoding undecaprenyl pyrophosphate (Und-PP) synthase, uppS, synergizes with ΔmlaF to increase susceptibility to membrane stress and antibiotics, and reduce persistence in a mouse lung infection. Und-P is a lipid glycan carrier known to be required for biosynthesis of A. baumannii capsule, cell wall, and glycoproteins. Our data suggest that in the absence of the Mla system, the cellular level of Und-P is critical for envelope integrity, antibiotic resistance, and lipooligosaccharide abundance. These findings uncover synergy between Und-P and the Mla system in maintaining the A. baumannii outer membrane and stress resistance.
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Affiliation(s)
- Hannah R. Noel
- Department of Microbiology and Immunology, University of Illinois Chicago, Chicago, IL, USA
| | - Sowmya Keerthi
- Department of Chemistry, University of North Carolina Charlotte, Charlotte, NC, USA
| | - Xiaomei Ren
- Department of Microbiology and Immunology, University of Illinois Chicago, Chicago, IL, USA
| | | | - Jerry M. Troutman
- Department of Chemistry, University of North Carolina Charlotte, Charlotte, NC, USA
| | - Lauren D. Palmer
- Department of Microbiology and Immunology, University of Illinois Chicago, Chicago, IL, USA
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4
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Lynch AM, Zhu Y, Lucas BG, Winkelman JD, Bai K, Martin SCT, Block S, Slabodnick MM, Audhya A, Goldstein B, Pettitt J, Gardel ML, Hardin J. TES-1/Tes and ZYX-1/Zyxin protect junctional actin networks under tension during epidermal morphogenesis in the C. elegans embryo. Curr Biol 2022; 32:5189-5199.e6. [PMID: 36384139 PMCID: PMC9729467 DOI: 10.1016/j.cub.2022.10.045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 09/12/2022] [Accepted: 10/19/2022] [Indexed: 11/17/2022]
Abstract
LIM-domain-containing repeat (LCR) proteins are recruited to strained actin filaments within stress fibers in cultured cells,1,2,3 but their roles at cell-cell junctions in living organisms have not been extensively studied. Here, we show that the Caenorhabditis elegans LCR proteins TES-1/Tes and ZYX-1/Zyxin are recruited to apical junctions during embryonic elongation when junctions are under tension. In genetic backgrounds in which embryonic elongation fails, junctional recruitment is severely compromised. The two proteins display complementary patterns of expression: TES-1 is expressed in lateral (seam) epidermal cells, whereas ZYX-1 is expressed in dorsal and ventral epidermal cells. tes-1 and zyx-1 mutant embryos display junctional F-actin defects. The loss of either protein strongly enhances morphogenetic defects in hypomorphic mutant backgrounds for cadherin/catenin complex (CCC) components. The LCR regions of TES-1 and ZYX-1 are recruited to stress fiber strain sites (SFSSs) in cultured vertebrate cells. Together, these data establish TES-1 and ZYX-1 as components of a multicellular, tension-sensitive system that stabilizes the junctional actin cytoskeleton during embryonic morphogenesis.
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Affiliation(s)
- Allison M Lynch
- Program in Genetics, University of Wisconsin, Madison, WI 53706, USA
| | - Yuyun Zhu
- Program in Genetics, University of Wisconsin, Madison, WI 53706, USA
| | - Bethany G Lucas
- Department of Biology, Regis University, 3333 Regis Boulevard, Denver, CO 80221, USA
| | - Jonathan D Winkelman
- Institute for Biophysical Dynamics, University of Chicago, Chicago, IL 60637, USA
| | - Keliya Bai
- University of Aberdeen, Institute of Medical Sciences, Aberdeen AB25 2ZD, UK
| | | | - Samuel Block
- Department of Biomolecular Chemistry, University of Wisconsin, Madison, WI 53706, USA
| | - Mark M Slabodnick
- Department of Biology, Knox University, Galesburg, IL 61401, USA; Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Anjon Audhya
- Department of Biomolecular Chemistry, University of Wisconsin, Madison, WI 53706, USA
| | - Bob Goldstein
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Jonathan Pettitt
- University of Aberdeen, Institute of Medical Sciences, Aberdeen AB25 2ZD, UK
| | - Margaret L Gardel
- Institute for Biophysical Dynamics, University of Chicago, Chicago, IL 60637, USA; Department of Physics, James Franck Institute and Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - Jeff Hardin
- Program in Genetics, University of Wisconsin, Madison, WI 53706, USA; Biophysics Program, University of Wisconsin, Madison, WI 53706, USA; Department of Integrative Biology, University of Wisconsin, Madison, WI 53706, USA.
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5
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Anderson CA, Kovar DR, Gardel ML, Winkelman JD. LIM domain proteins in cell mechanobiology. Cytoskeleton (Hoboken) 2021; 78:303-311. [PMID: 34028199 DOI: 10.1002/cm.21677] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 05/06/2021] [Accepted: 05/07/2021] [Indexed: 12/13/2022]
Abstract
The actin cytoskeleton is important for maintaining mechanical homeostasis in adherent cells, largely through its regulation of adhesion and cortical tension. The LIM (Lin-11, Isl1, MEC-3) domain-containing proteins are involved in a myriad of cellular mechanosensitive pathways. Recent work has discovered that LIM domains bind to mechanically stressed actin filaments, suggesting a novel and widely conserved mechanism of mechanosensing. This review summarizes the current state of knowledge of LIM protein mechanosensitivity.
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Affiliation(s)
- Caitlin A Anderson
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois, USA
| | - David R Kovar
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois, USA.,Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois, USA
| | - Margaret L Gardel
- Institute for Biophysical Dynamics, University of Chicago, Chicago, Illinois, USA.,James Franck Institute, University of Chicago, Chicago, Illinois, USA.,Department of Physics, University of Chicago, Chicago, Illinois, USA.,Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois, USA
| | - Jonathan D Winkelman
- Institute for Biophysical Dynamics, University of Chicago, Chicago, Illinois, USA
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Winkelman JD, Anderson CA, Suarez C, Kovar DR, Gardel ML. Evolutionarily diverse LIM domain-containing proteins bind stressed actin filaments through a conserved mechanism. Proc Natl Acad Sci U S A 2020; 117:25532-25542. [PMID: 32989126 PMCID: PMC7568268 DOI: 10.1073/pnas.2004656117] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The actin cytoskeleton assembles into diverse load-bearing networks, including stress fibers (SFs), muscle sarcomeres, and the cytokinetic ring to both generate and sense mechanical forces. The LIM (Lin11, Isl- 1, and Mec-3) domain family is functionally diverse, but most members can associate with the actin cytoskeleton with apparent force sensitivity. Zyxin rapidly localizes via its LIM domains to failing SFs in cells, known as strain sites, to initiate SF repair and maintain mechanical homeostasis. The mechanism by which these LIM domains associate with stress fiber strain sites (SFSS) is not known. Additionally, it is unknown how widespread strain sensing is within the LIM protein family. We identify that the LIM domain-containing region of 18 proteins from the Zyxin, Paxillin, Tes, and Enigma proteins accumulate to SFSS. Moreover, the LIM domain region from the fission yeast protein paxillin like 1 (Pxl1) also localizes to SFSS in mammalian cells, suggesting that the strain sensing mechanism is ancient and highly conserved. We then used sequence and domain analysis to demonstrate that tandem LIM domains contribute additively, for SFSS localization. Employing in vitro reconstitution, we show that the LIM domain-containing region from mammalian zyxin and fission yeast Pxl1 binds to mechanically stressed F-actin networks but does not associate with relaxed actin filaments. We propose that tandem LIM domains recognize an F-actin conformation that is rare in the relaxed state but is enriched in the presence of mechanical stress.
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Affiliation(s)
| | - Caitlin A Anderson
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637
| | - Cristian Suarez
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637
| | - David R Kovar
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637;
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60637
| | - Margaret L Gardel
- Institute for Biophysical Dynamics, University of Chicago, Chicago, IL 60637;
- James Franck Institute, University of Chicago, Chicago, IL 60637
- Physics Department, University of Chicago, Chicago, IL 60637
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637
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7
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Winkelman JD, Suarez C, Hocky GM, Harker AJ, Morganthaler AN, Christensen JR, Voth GA, Bartles JR, Kovar DR. Fascin- and α-Actinin-Bundled Networks Contain Intrinsic Structural Features that Drive Protein Sorting. Curr Biol 2016; 26:2697-2706. [PMID: 27666967 DOI: 10.1016/j.cub.2016.07.080] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 07/04/2016] [Accepted: 07/28/2016] [Indexed: 12/25/2022]
Abstract
Cells assemble and maintain functionally distinct actin cytoskeleton networks with various actin filament organizations and dynamics through the coordinated action of different sets of actin-binding proteins. The biochemical and functional properties of diverse actin-binding proteins, both alone and in combination, have been increasingly well studied. Conversely, how different sets of actin-binding proteins properly sort to distinct actin filament networks in the first place is not nearly as well understood. Actin-binding protein sorting is critical for the self-organization of diverse dynamic actin cytoskeleton networks within a common cytoplasm. Using in vitro reconstitution techniques including biomimetic assays and single-molecule multi-color total internal reflection fluorescence microscopy, we discovered that sorting of the prominent actin-bundling proteins fascin and α-actinin to distinct networks is an intrinsic behavior, free of complicated cellular signaling cascades. When mixed, fascin and α-actinin mutually exclude each other by promoting their own recruitment and inhibiting recruitment of the other, resulting in the formation of distinct fascin- or α-actinin-bundled domains. Subdiffraction-resolution light microscopy and negative-staining electron microscopy revealed that fascin domains are densely packed, whereas α-actinin domains consist of widely spaced parallel actin filaments. Importantly, other actin-binding proteins such as fimbrin and espin show high specificity between these two bundle types within the same reaction. Here we directly observe that fascin and α-actinin intrinsically segregate to discrete bundled domains that are specifically recognized by other actin-binding proteins.
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Affiliation(s)
- Jonathan D Winkelman
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Cristian Suarez
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Glen M Hocky
- Department of Chemistry, The University of Chicago, Chicago, IL 60637, USA; James Franck Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Alyssa J Harker
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Alisha N Morganthaler
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Jenna R Christensen
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Gregory A Voth
- Department of Chemistry, The University of Chicago, Chicago, IL 60637, USA; James Franck Institute, The University of Chicago, Chicago, IL 60637, USA; Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA; Computation Institute, The University of Chicago, Chicago, IL 60637, USA
| | - James R Bartles
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - David R Kovar
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA; Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA.
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8
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Heisler DB, Kudryashova E, Grinevich DO, Suarez C, Winkelman JD, Birukov KG, Kotha SR, Parinandi NL, Vavylonis D, Kovar DR, Kudryashov DS. ACTIN-DIRECTED TOXIN. ACD toxin-produced actin oligomers poison formin-controlled actin polymerization. Science 2015; 349:535-9. [PMID: 26228148 DOI: 10.1126/science.aab4090] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The actin cross-linking domain (ACD) is an actin-specific toxin produced by several pathogens, including life-threatening spp. of Vibrio cholerae, Vibrio vulnificus, and Aeromonas hydrophila. Actin cross-linking by ACD is thought to lead to slow cytoskeleton failure owing to a gradual sequestration of actin in the form of nonfunctional oligomers. Here, we found that ACD converted cytoplasmic actin into highly toxic oligomers that potently "poisoned" the ability of major actin assembly proteins, formins, to sustain actin polymerization. Thus, ACD can target the most abundant cellular protein by using actin oligomers as secondary toxins to efficiently subvert cellular functions of actin while functioning at very low doses.
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Affiliation(s)
- David B Heisler
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA. The Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
| | - Elena Kudryashova
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA.
| | - Dmitry O Grinevich
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Cristian Suarez
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Jonathan D Winkelman
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Konstantin G Birukov
- Section of Pulmonary and Critical Care and Lung Injury Center, Department of Medicine, The University of Chicago, Chicago, IL 60637, USA
| | - Sainath R Kotha
- Lipid Signaling and Lipidomics Laboratory, Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Narasimham L Parinandi
- Lipid Signaling and Lipidomics Laboratory, Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
| | | | - David R Kovar
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA. Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Dmitri S Kudryashov
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA. The Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA.
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9
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Rotty JD, Wu C, Haynes EM, Suarez C, Winkelman JD, Johnson HE, Haugh JM, Kovar DR, Bear JE. Profilin-1 serves as a gatekeeper for actin assembly by Arp2/3-dependent and -independent pathways. Dev Cell 2014; 32:54-67. [PMID: 25543281 DOI: 10.1016/j.devcel.2014.10.026] [Citation(s) in RCA: 193] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Revised: 09/12/2014] [Accepted: 10/30/2014] [Indexed: 12/31/2022]
Abstract
Cells contain multiple F-actin assembly pathways, including the Arp2/3 complex, formins, and Ena/VASP, which have largely been analyzed separately. They collectively generate the bulk of F-actin from a common pool of G-actin; however, the interplay and/or competition between these pathways remains poorly understood. Using fibroblast lines derived from an Arpc2 conditional knockout mouse, we established matched-pair cells with and without the Arp2/3 complex. Arpc2(-/-) cells lack lamellipodia and migrate more slowly than WT cells but have F-actin levels indistinguishable from controls. Actin assembly in Arpc2(-/-) cells was resistant to cytochalasin-D and was highly dependent on profilin-1 and Ena/VASP but not formins. Profilin-1 depletion in WT cells increased F-actin and Arp2/3 complex in lamellipodia. Conversely, addition of exogenous profilin-1 inhibited Arp2/3 complex actin nucleation in vitro and in vivo. Antagonism of the Arp2/3 complex by profilin-1 in cells appears to maintain actin homeostasis by balancing Arp2/3 complex-dependent and -independent actin assembly pathways.
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Affiliation(s)
- Jeremy D Rotty
- University of North Carolina Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Howard Hughes Medical Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Congying Wu
- University of North Carolina Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Howard Hughes Medical Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Elizabeth M Haynes
- University of North Carolina Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Cristian Suarez
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Jonathan D Winkelman
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Heath E Johnson
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA
| | - Jason M Haugh
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA
| | - David R Kovar
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA; Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA
| | - James E Bear
- University of North Carolina Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Howard Hughes Medical Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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10
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Bilancia CG, Winkelman JD, Tsygankov D, Nowotarski SH, Sees JA, Comber K, Evans I, Lakhani V, Wood W, Elston TC, Kovar DR, Peifer M. Enabled negatively regulates diaphanous-driven actin dynamics in vitro and in vivo. Dev Cell 2014; 28:394-408. [PMID: 24576424 PMCID: PMC3992947 DOI: 10.1016/j.devcel.2014.01.015] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Revised: 12/20/2013] [Accepted: 01/15/2014] [Indexed: 11/03/2022]
Abstract
Actin regulators facilitate cell migration by controlling cell protrusion architecture and dynamics. As the behavior of individual actin regulators becomes clear, we must address why cells require multiple regulators with similar functions and how they cooperate to create diverse protrusions. We characterized Diaphanous (Dia) and Enabled (Ena) as a model, using complementary approaches: cell culture, biophysical analysis, and Drosophila morphogenesis. We found that Dia and Ena have distinct biochemical properties that contribute to the different protrusion morphologies each induces. Dia is a more processive, faster elongator, paralleling the long, stable filopodia it induces in vivo, while Ena promotes filopodia with more dynamic changes in number, length, and lifetime. Acting together, Ena and Dia induce protrusions distinct from those induced by either alone, with Ena reducing Dia-driven protrusion length and number. Consistent with this, EnaEVH1 binds Dia directly and inhibits DiaFH1FH2-mediated nucleation in vitro. Finally, Ena rescues hemocyte migration defects caused by activated Dia. Dia and Ena differ biochemically, promoting distinct filopodia dynamics Dia and Ena colocalization negatively regulates filopodia Ena’s EVH1 binds Dia’s FH1 and reduces Dia-driven filopodia and actin nucleation Ena rescues DiaΔDAD inhibition of hemocyte migration speed to wounds in vivo
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Affiliation(s)
- Colleen G Bilancia
- Biology Department, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Jonathan D Winkelman
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Denis Tsygankov
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Stephanie H Nowotarski
- Biology Department, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Jennifer A Sees
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Kate Comber
- Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK
| | - Iwan Evans
- Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK
| | - Vinal Lakhani
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Will Wood
- Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK
| | - Timothy C Elston
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - David R Kovar
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA; Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Mark Peifer
- Biology Department, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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11
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Namgoong S, Boczkowska M, Glista MJ, Winkelman JD, Rebowski G, Kovar DR, Dominguez R. Mechanism of actin filament nucleation by Vibrio VopL and implications for tandem W domain nucleation. Nat Struct Mol Biol 2011; 18:1060-7. [PMID: 21873985 PMCID: PMC3173040 DOI: 10.1038/nsmb.2109] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 06/30/2011] [Indexed: 11/09/2022]
Abstract
Pathogen proteins targeting the actin cytoskeleton often serve as model systems to understand their more complex eukaryotic analogs. We show that the strong actin filament nucleation activity of Vibrio parahaemolyticus VopL depends on its three W domains and on its dimerization through a unique VopL C-terminal domain (VCD). The VCD shows a previously unknown all-helical fold and interacts with the pointed end of the actin nucleus, contributing to the nucleation activity directly and through duplication of the W domain repeat. VopL promotes rapid cycles of filament nucleation and detachment but generally has no effect on elongation. Profilin inhibits VopL-induced nucleation by competing for actin binding to the W domains. Combined, the results suggest that VopL stabilizes a hexameric double-stranded pointed end nucleus. Analysis of hybrid constructs of VopL and the eukaryotic nucleator Spire suggest that Spire may also function as a dimer in cells.
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Affiliation(s)
- Suk Namgoong
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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12
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Skau CT, Courson DS, Bestul AJ, Winkelman JD, Rock RS, Sirotkin V, Kovar DR. Actin filament bundling by fimbrin is important for endocytosis, cytokinesis, and polarization in fission yeast. J Biol Chem 2011; 286:26964-77. [PMID: 21642440 DOI: 10.1074/jbc.m111.239004] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Through the coordinated action of diverse actin-binding proteins, cells simultaneously assemble actin filaments with distinct architectures and dynamics to drive different processes. Actin filament cross-linking proteins organize filaments into higher order networks, although the requirement of cross-linking activity in cells has largely been assumed rather than directly tested. Fission yeast Schizosaccharomyces pombe assembles actin into three discrete structures: endocytic actin patches, polarizing actin cables, and the cytokinetic contractile ring. The fission yeast filament cross-linker fimbrin Fim1 primarily localizes to Arp2/3 complex-nucleated branched filaments of the actin patch and by a lesser amount to bundles of linear antiparallel filaments in the contractile ring. It is unclear whether Fim1 associates with bundles of parallel filaments in actin cables. We previously discovered that a principal role of Fim1 is to control localization of tropomyosin Cdc8, thereby facilitating cofilin-mediated filament turnover. Therefore, we hypothesized that the bundling ability of Fim1 is dispensable for actin patches but is important for the contractile ring and possibly actin cables. By directly visualizing actin filament assembly using total internal reflection fluorescence microscopy, we determined that Fim1 bundles filaments in both parallel and antiparallel orientations and efficiently bundles Arp2/3 complex-branched filaments in the absence but not the presence of actin capping protein. Examination of cells exclusively expressing a truncated version of Fim1 that can bind but not bundle actin filaments revealed that bundling activity of Fim1 is in fact important for all three actin structures. Therefore, fimbrin Fim1 has diverse roles as both a filament "gatekeeper" and as a filament cross-linker.
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Affiliation(s)
- Colleen T Skau
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago Illinois 60637, USA
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