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Niedzialkowska E, Runyan LA, Kudryashova E, Egelman EH, Kudryashov DS. Stabilization of F-actin by Salmonella effector SipA resembles the structural effects of inorganic phosphate and phalloidin. Structure 2024; 32:725-738.e8. [PMID: 38518780 PMCID: PMC11162321 DOI: 10.1016/j.str.2024.02.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 02/08/2024] [Accepted: 02/26/2024] [Indexed: 03/24/2024]
Abstract
Entry of Salmonella into host enterocytes relies on its pathogenicity island 1 effector SipA. We found that SipA binds to F-actin in a 1:2 stoichiometry with sub-nanomolar affinity. A cryo-EM reconstruction revealed that SipA's globular core binds at the groove between actin strands, whereas the extended C-terminal arm penetrates deeply into the inter-strand space, stabilizing F-actin from within. The unusually strong binding of SipA is achieved by a combination of fast association via the core and very slow dissociation dictated by the arm. Similar to Pi, BeF3, and phalloidin, SipA potently inhibited actin depolymerization by actin depolymerizing factor (ADF)/cofilin, which correlated with increased filament stiffness, supporting the hypothesis that F-actin's mechanical properties contribute to the recognition of its nucleotide state by protein partners. The remarkably strong binding to F-actin maximizes the toxin's effects at the injection site while minimizing global influence on the cytoskeleton and preventing pathogen detection by the host cell.
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Affiliation(s)
- Ewa Niedzialkowska
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22903, USA
| | - Lucas A Runyan
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Elena Kudryashova
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Edward H Egelman
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22903, USA.
| | - Dmitri S Kudryashov
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA.
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2
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Niedzialkowska E, Runyan LA, Kudryashova E, Egelman EH, Kudryashov DS. Stabilization of F-actin by Salmonella effector SipA resembles the structural effects of inorganic phosphate and phalloidin. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.26.573373. [PMID: 38234808 PMCID: PMC10793455 DOI: 10.1101/2023.12.26.573373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
Entry of Salmonella into host enterocytes strictly relies on its pathogenicity island 1 effector SipA. We found that SipA binds to F-actin in a unique mode in a 1:2 stoichiometry with picomolar affinity. A cryo-EM reconstruction revealed that SipA's globular core binds at the grove between actin strands, whereas the extended C-terminal arm penetrates deeply into the inter-strand space, stabilizing F-actin from within. The unusually strong binding of SipA is achieved via a combination of fast association via the core and very slow dissociation dictated by the arm. Similarly to Pi, BeF3, and phalloidin, SipA potently inhibited actin depolymerization by ADF/cofilin, which correlated with the increased filament stiffness, supporting the hypothesis that F-actin's mechanical properties contribute to the recognition of its nucleotide state by protein partners. The remarkably strong binding to F-actin maximizes the toxin's effects at the injection site while minimizing global influence on the cytoskeleton and preventing pathogen detection by the host cell.
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Affiliation(s)
- Ewa Niedzialkowska
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22903, USA
| | - Lucas A. Runyan
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Elena Kudryashova
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Edward H. Egelman
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22903, USA
| | - Dmitri S. Kudryashov
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
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3
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Zhang Q, Wan M, Kudryashova E, Kudryashov DS, Mao Y. Membrane-dependent actin polymerization mediated by the Legionella pneumophila effector protein MavH. PLoS Pathog 2023; 19:e1011512. [PMID: 37463171 PMCID: PMC10381072 DOI: 10.1371/journal.ppat.1011512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 06/26/2023] [Indexed: 07/20/2023] Open
Abstract
L. pneumophila propagates in eukaryotic cells within a specialized niche, the Legionella-containing vacuole (LCV). The infection process is controlled by over 330 effector proteins delivered through the type IV secretion system. In this study, we report that the Legionella MavH effector localizes to endosomes and remodels host actin cytoskeleton in a phosphatidylinositol 3-phosphate (PI(3)P) dependent manner when ectopically expressed. We show that MavH recruits host actin capping protein (CP) and actin to the endosome via its CP-interacting (CPI) motif and WH2-like actin-binding domain, respectively. In vitro assays revealed that MavH stimulates actin assembly on PI(3)P-containing liposomes causing their tubulation. In addition, the recruitment of CP by MavH negatively regulates F-actin density at the membrane. We further show that, in L. pneumophila-infected cells, MavH appears around the LCV at the very early stage of infection and facilitates bacterium entry into the host. Together, our results reveal a novel mechanism of membrane tubulation induced by membrane-dependent actin polymerization catalyzed by MavH that contributes to the early stage of L. pneumophila infection by regulating host actin dynamics.
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Affiliation(s)
- Qing Zhang
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York, United States of America
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
| | - Min Wan
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York, United States of America
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
| | - Elena Kudryashova
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, United States of America
| | - Dmitri S Kudryashov
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, United States of America
| | - Yuxin Mao
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York, United States of America
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
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4
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Kudryashova E, Ankita, Ulrichs H, Shekhar S, Kudryashov DS. Pointed-end processive elongation of actin filaments by Vibrio effectors VopF and VopL. SCIENCE ADVANCES 2022; 8:eadc9239. [PMID: 36399577 PMCID: PMC9674292 DOI: 10.1126/sciadv.adc9239] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 10/03/2022] [Indexed: 07/20/2023]
Abstract
According to the cellular actin dynamics paradigm, filaments grow at their barbed ends and depolymerize predominantly from their pointed ends to form polar structures and do productive work. We show that actin can elongate at the pointed end when assisted by Vibrio VopF/L toxins, which act as processive polymerases. In cells, processively moving VopF/L speckles are inhibited by factors blocking the pointed but not barbed ends. Multispectral single-molecule imaging confirmed that VopF molecules associate with the pointed end, actively promoting its elongation even in the presence of profilin. Consequently, VopF/L can break the actin cytoskeleton's polarity by compromising actin-based cellular processes. Therefore, actin filament design allows processive growth at both ends, which suggests unforeseen possibilities for cellular actin organization, particularly in specialized cells and compartments.
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Affiliation(s)
- Elena Kudryashova
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Ankita
- Department of Physics, Emory University, Atlanta, GA 30322, USA
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA
| | - Heidi Ulrichs
- Department of Physics, Emory University, Atlanta, GA 30322, USA
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA
| | - Shashank Shekhar
- Department of Physics, Emory University, Atlanta, GA 30322, USA
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA
| | - Dmitri S. Kudryashov
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
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5
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Li Y, Wang D, Ge H, Güngör C, Gong X, Chen Y. Cytoskeletal and Cytoskeleton-Associated Proteins: Key Regulators of Cancer Stem Cell Properties. Pharmaceuticals (Basel) 2022; 15:1369. [PMID: 36355541 PMCID: PMC9698833 DOI: 10.3390/ph15111369] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Revised: 11/02/2022] [Accepted: 11/06/2022] [Indexed: 08/08/2023] Open
Abstract
Cancer stem cells (CSCs) are a subpopulation of cancer cells possessing stemness characteristics that are closely associated with tumor proliferation, recurrence and resistance to therapy. Recent studies have shown that different cytoskeletal components and remodeling processes have a profound impact on the behavior of CSCs. In this review, we outline the different cytoskeletal components regulating the properties of CSCs and discuss current and ongoing therapeutic strategies targeting the cytoskeleton. Given the many challenges currently faced in targeted cancer therapy, a deeper comprehension of the molecular events involved in the interaction of the cytoskeleton and CSCs will help us identify more effective therapeutic strategies to eliminate CSCs and ultimately improve patient survival.
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Affiliation(s)
- Yuqiang Li
- Department of General Surgery, Xiangya Hospital, Central South University, Changsha 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, China
- NHC Key Laboratory of Cancer Proteomics, Laboratory of Structural Biology, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Dan Wang
- Department of General Surgery, Xiangya Hospital, Central South University, Changsha 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, China
- Department of General Visceral and Thoracic Surgery, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Heming Ge
- Department of General Surgery, Xiangya Hospital, Central South University, Changsha 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, China
- Department of General Visceral and Thoracic Surgery, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Cenap Güngör
- Department of General Visceral and Thoracic Surgery, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Xuejun Gong
- Department of General Surgery, Xiangya Hospital, Central South University, Changsha 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Yongheng Chen
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, China
- NHC Key Laboratory of Cancer Proteomics, Laboratory of Structural Biology, Xiangya Hospital, Central South University, Changsha 410008, China
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6
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Dong S, Zheng W, Pinkerton N, Hansen J, Tikunova SB, Davis JP, Heissler SM, Kudryashova E, Egelman EH, Kudryashov DS. Photorhabdus luminescens TccC3 Toxin Targets the Dynamic Population of F-Actin and Impairs Cell Cortex Integrity. Int J Mol Sci 2022; 23:7026. [PMID: 35806028 PMCID: PMC9266650 DOI: 10.3390/ijms23137026] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 06/17/2022] [Accepted: 06/22/2022] [Indexed: 12/30/2022] Open
Abstract
Due to its essential role in cellular processes, actin is a common target for bacterial toxins. One such toxin, TccC3, is an effector domain of the ABC-toxin produced by entomopathogenic bacteria of Photorhabdus spp. Unlike other actin-targeting toxins, TccC3 uniquely ADP-ribosylates actin at Thr-148, resulting in the formation of actin aggregates and inhibition of phagocytosis. It has been shown that the fully modified F-actin is resistant to depolymerization by cofilin and gelsolin, but their effects on partially modified actin were not explored. We found that only F-actin unprotected by tropomyosin is the physiological TccC3 substrate. Yet, ADP-ribosylated G-actin can be produced upon cofilin-accelerated F-actin depolymerization, which was only mildly inhibited in partially modified actin. The affinity of TccC3-ADP-ribosylated G-actin for profilin and thymosin-β4 was weakened moderately but sufficiently to potentiate spontaneous polymerization in their presence. Interestingly, the Arp2/3-mediated nucleation was also potentiated by T148-ADP-ribosylation. Notably, even partially modified actin showed reduced bundling by plastins and α-actinin. In agreement with the role of these and other tandem calponin-homology domain actin organizers in the assembly of the cortical actin network, TccC3 induced intense membrane blebbing in cultured cells. Overall, our data suggest that TccC3 imposes a complex action on the cytoskeleton by affecting F-actin nucleation, recycling, and interaction with actin-binding proteins involved in the integration of actin filaments with each other and cellular elements.
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Affiliation(s)
- Songyu Dong
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; (S.D.); (N.P.); (J.H.); (E.K.)
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
| | - Weili Zheng
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22903, USA; (W.Z.); (E.H.E.)
| | - Nicholas Pinkerton
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; (S.D.); (N.P.); (J.H.); (E.K.)
| | - Jacob Hansen
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; (S.D.); (N.P.); (J.H.); (E.K.)
| | - Svetlana B. Tikunova
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA; (S.B.T.); (J.P.D.); (S.M.H.)
| | - Jonathan P. Davis
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA; (S.B.T.); (J.P.D.); (S.M.H.)
| | - Sarah M. Heissler
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA; (S.B.T.); (J.P.D.); (S.M.H.)
| | - Elena Kudryashova
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; (S.D.); (N.P.); (J.H.); (E.K.)
| | - Edward H. Egelman
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22903, USA; (W.Z.); (E.H.E.)
| | - Dmitri S. Kudryashov
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; (S.D.); (N.P.); (J.H.); (E.K.)
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
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7
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Allosteric regulation controls actin-bundling properties of human plastins. Nat Struct Mol Biol 2022; 29:519-528. [PMID: 35589838 DOI: 10.1038/s41594-022-00771-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 04/05/2022] [Indexed: 11/08/2022]
Abstract
Plastins/fimbrins are conserved actin-bundling proteins contributing to motility, cytokinesis and other cellular processes by organizing strikingly different actin assemblies as in aligned bundles and branched networks. We propose that this ability of human plastins stems from an allosteric communication between their actin-binding domains (ABD1/2) engaged in a tight spatial association. Here we show that ABD2 can bind actin three orders of magnitude stronger than ABD1, unless the domains are involved in an equally strong inhibitory engagement. A mutation mimicking physiologically relevant phosphorylation at the ABD1-ABD2 interface greatly weakened their association, dramatically potentiating actin cross-linking. Cryo-EM reconstruction revealed the ABD1-actin interface and enabled modeling of the plastin bridge and domain separation in parallel bundles. We predict that a strong and tunable allosteric inhibition between the domains allows plastins to modulate the cross-linking strength, contributing to remodeling of actin assemblies of different morphologies defining the unique place of plastins in actin organization.
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8
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Kraus J, Russell RW, Kudryashova E, Xu C, Katyal N, Perilla JR, Kudryashov DS, Polenova T. Magic angle spinning NMR structure of human cofilin-2 assembled on actin filaments reveals isoform-specific conformation and binding mode. Nat Commun 2022; 13:2114. [PMID: 35440100 PMCID: PMC9018683 DOI: 10.1038/s41467-022-29595-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 03/24/2022] [Indexed: 12/16/2022] Open
Abstract
Actin polymerization dynamics regulated by actin-binding proteins are essential for various cellular functions. The cofilin family of proteins are potent regulators of actin severing and filament disassembly. The structural basis for cofilin-isoform-specific severing activity is poorly understood as their high-resolution structures in complex with filamentous actin (F-actin) are lacking. Here, we present the atomic-resolution structure of the muscle-tissue-specific isoform, cofilin-2 (CFL2), assembled on ADP-F-actin, determined by magic-angle-spinning (MAS) NMR spectroscopy and data-guided molecular dynamics (MD) simulations. We observe an isoform-specific conformation for CFL2. This conformation is the result of a unique network of hydrogen bonding interactions within the α2 helix containing the non-conserved residue, Q26. Our results indicate F-site interactions that are specific between CFL2 and ADP-F-actin, revealing mechanistic insights into isoform-dependent F-actin disassembly.
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Affiliation(s)
- Jodi Kraus
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, United States
- Department of Molecular Biology, Princeton University, Princeton, NJ, 08544-1014, United States
| | - Ryan W Russell
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, United States
| | - Elena Kudryashova
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210, United States
| | - Chaoyi Xu
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, United States
| | - Nidhi Katyal
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, United States
| | - Juan R Perilla
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, United States
| | - Dmitri S Kudryashov
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210, United States
| | - Tatyana Polenova
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, United States.
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9
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MacTaggart B, Kashina A. Posttranslational modifications of the cytoskeleton. Cytoskeleton (Hoboken) 2021; 78:142-173. [PMID: 34152688 DOI: 10.1002/cm.21679] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 06/13/2021] [Accepted: 06/16/2021] [Indexed: 12/12/2022]
Abstract
The cytoskeleton plays important roles in many essential processes at the cellular and organismal levels, including cell migration and motility, cell division, and the establishment and maintenance of cell and tissue architecture. In order to facilitate these varied functions, the main cytoskeletal components-microtubules, actin filaments, and intermediate filaments-must form highly diverse intracellular arrays in different subcellular areas and cell types. The question of how this diversity is conferred has been the focus of research for decades. One key mechanism is the addition of posttranslational modifications (PTMs) to the major cytoskeletal proteins. This posttranslational addition of various chemical groups dramatically increases the complexity of the cytoskeletal proteome and helps facilitate major global and local cytoskeletal functions. Cytoskeletal proteins undergo many PTMs, most of which are not well understood. Recent technological advances in proteomics and cell biology have allowed for the in-depth study of individual PTMs and their functions in the cytoskeleton. Here, we provide an overview of the major PTMs that occur on the main structural components of the three cytoskeletal systems-tubulin, actin, and intermediate filament proteins-and highlight the cellular function of these modifications.
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Affiliation(s)
- Brittany MacTaggart
- School of Veterinary Medicine, Department of Biomedical Sciences, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Anna Kashina
- School of Veterinary Medicine, Department of Biomedical Sciences, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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10
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Smith H, Pinkerton N, Heisler DB, Kudryashova E, Hall AR, Karch KR, Norris A, Wysocki V, Sotomayor M, Reisler E, Vavylonis D, Kudryashov DS. Rounding Out the Understanding of ACD Toxicity with the Discovery of Cyclic Forms of Actin Oligomers. Int J Mol Sci 2021; 22:E718. [PMID: 33450834 PMCID: PMC7828245 DOI: 10.3390/ijms22020718] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 12/30/2020] [Accepted: 01/09/2021] [Indexed: 11/17/2022] Open
Abstract
Actin is an essential element of both innate and adaptive immune systems and can aid in motility and translocation of bacterial pathogens, making it an attractive target for bacterial toxins. Pathogenic Vibrio and Aeromonas genera deliver actin cross-linking domain (ACD) toxin into the cytoplasm of the host cell to poison actin regulation and promptly induce cell rounding. At early stages of toxicity, ACD covalently cross-links actin monomers into oligomers (AOs) that bind through multivalent interactions and potently inhibit several families of actin assembly proteins. At advanced toxicity stages, we found that the terminal protomers of linear AOs can get linked together by ACD to produce cyclic AOs. When tested against formins and Ena/VASP, linear and cyclic AOs exhibit similar inhibitory potential, which for the cyclic AOs is reduced in the presence of profilin. In coarse-grained molecular dynamics simulations, profilin and WH2-motif binding sites on actin subunits remain exposed in modeled AOs of both geometries. We speculate, therefore, that the reduced toxicity of cyclic AOs is due to their reduced configurational entropy. A characteristic feature of cyclic AOs is that, in contrast to the linear forms, they cannot be straightened to form filaments (e.g., through stabilization by cofilin), which makes them less susceptible to neutralization by the host cell.
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Affiliation(s)
- Harper Smith
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; (H.S.); (N.P.); (D.B.H.); (E.K.); (K.R.K.); (A.N.); (V.W.); (M.S.)
- Biophysics Graduate Program, The Ohio State University, Columbus, OH 43210, USA
| | - Nick Pinkerton
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; (H.S.); (N.P.); (D.B.H.); (E.K.); (K.R.K.); (A.N.); (V.W.); (M.S.)
| | - David B. Heisler
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; (H.S.); (N.P.); (D.B.H.); (E.K.); (K.R.K.); (A.N.); (V.W.); (M.S.)
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
- Infectious Diseases Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Elena Kudryashova
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; (H.S.); (N.P.); (D.B.H.); (E.K.); (K.R.K.); (A.N.); (V.W.); (M.S.)
- Infectious Diseases Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Aaron R. Hall
- Department of Physics, Lehigh University, Bethlehem, PA 18015, USA; (A.R.H.); (D.V.)
| | - Kelly R. Karch
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; (H.S.); (N.P.); (D.B.H.); (E.K.); (K.R.K.); (A.N.); (V.W.); (M.S.)
| | - Andrew Norris
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; (H.S.); (N.P.); (D.B.H.); (E.K.); (K.R.K.); (A.N.); (V.W.); (M.S.)
| | - Vicki Wysocki
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; (H.S.); (N.P.); (D.B.H.); (E.K.); (K.R.K.); (A.N.); (V.W.); (M.S.)
| | - Marcos Sotomayor
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; (H.S.); (N.P.); (D.B.H.); (E.K.); (K.R.K.); (A.N.); (V.W.); (M.S.)
- Biophysics Graduate Program, The Ohio State University, Columbus, OH 43210, USA
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
| | - Emil Reisler
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA;
| | - Dimitrios Vavylonis
- Department of Physics, Lehigh University, Bethlehem, PA 18015, USA; (A.R.H.); (D.V.)
| | - Dmitri S. Kudryashov
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; (H.S.); (N.P.); (D.B.H.); (E.K.); (K.R.K.); (A.N.); (V.W.); (M.S.)
- Biophysics Graduate Program, The Ohio State University, Columbus, OH 43210, USA
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
- Infectious Diseases Institute, The Ohio State University, Columbus, OH 43210, USA
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11
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Purde V, Kudryashova E, Heisler DB, Shakya R, Kudryashov DS. Intein-mediated cytoplasmic reconstitution of a split toxin enables selective cell ablation in mixed populations and tumor xenografts. Proc Natl Acad Sci U S A 2020; 117:22090-22100. [PMID: 32839344 PMCID: PMC7486740 DOI: 10.1073/pnas.2006603117] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The application of proteinaceous toxins for cell ablation is limited by their high on- and off-target toxicity, severe side effects, and a narrow therapeutic window. The selectivity of targeting can be improved by intein-based toxin reconstitution from two dysfunctional fragments provided their cytoplasmic delivery via independent, selective pathways. While the reconstitution of proteins from genetically encoded elements has been explored, exploiting cell-surface receptors for boosting selectivity has not been attained. We designed a robust splitting algorithm and achieved reliable cytoplasmic reconstitution of functional diphtheria toxin from engineered intein-flanked fragments upon receptor-mediated delivery of one of them to the cells expressing the counterpart. Retargeting the delivery machinery toward different receptors overexpressed in cancer cells enables selective ablation of specific subpopulations in mixed cell cultures. In a mouse model, the transmembrane delivery of a split-toxin construct potently inhibits the growth of xenograft tumors expressing the split counterpart. Receptor-mediated delivery of engineered split proteins provides a platform for precise therapeutic and experimental ablation of tumors or desired cell populations while also greatly expanding the applicability of the intein-based protein transsplicing.
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Affiliation(s)
- Vedud Purde
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210
| | - Elena Kudryashova
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210;
| | - David B Heisler
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210
| | - Reena Shakya
- Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210
| | - Dmitri S Kudryashov
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210;
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210
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12
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Schwebach CL, Kudryashova E, Zheng W, Orchard M, Smith H, Runyan LA, Egelman EH, Kudryashov DS. Osteogenesis imperfecta mutations in plastin 3 lead to impaired calcium regulation of actin bundling. Bone Res 2020; 8:21. [PMID: 32509377 PMCID: PMC7244493 DOI: 10.1038/s41413-020-0095-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 02/06/2020] [Accepted: 03/23/2020] [Indexed: 12/11/2022] Open
Abstract
Mutations in actin-bundling protein plastin 3 (PLS3) emerged as a cause of congenital osteoporosis, but neither the role of PLS3 in bone development nor the mechanisms underlying PLS3-dependent osteoporosis are understood. Of the over 20 identified osteoporosis-linked PLS3 mutations, we investigated all five that are expected to produce full-length protein. One of the mutations distorted an actin-binding loop in the second actin-binding domain of PLS3 and abolished F-actin bundling as revealed by cryo-EM reconstruction and protein interaction assays. Surprisingly, the remaining four mutants fully retained F-actin bundling ability. However, they displayed defects in Ca2+ sensitivity: two of the mutants lost the ability to be inhibited by Ca2+, while the other two became hypersensitive to Ca2+. Each group of the mutants with similar biochemical properties showed highly characteristic cellular behavior. Wild-type PLS3 was distributed between lamellipodia and focal adhesions. In striking contrast, the Ca2+-hyposensitive mutants were not found at the leading edge but localized exclusively at focal adhesions/stress fibers, which displayed reinforced morphology. Consistently, the Ca2+-hypersensitive PLS3 mutants were restricted to lamellipodia, while chelation of Ca2+ caused their redistribution to focal adhesions. Finally, the bundling-deficient mutant failed to co-localize with any F-actin structures in cells despite a preserved F-actin binding through a non-mutation-bearing actin-binding domain. Our findings revealed that severe osteoporosis can be caused by a mutational disruption of the Ca2+-controlled PLS3's cycling between adhesion complexes and the leading edge. Integration of the structural, biochemical, and cell biology insights enabled us to propose a molecular mechanism of plastin activity regulation by Ca2+.
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Affiliation(s)
- Christopher L. Schwebach
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210 USA
- Molecular Cellular and Developmental Biology graduate program, The Ohio State University, Columbus, OH 43210 USA
| | - Elena Kudryashova
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210 USA
| | - Weili Zheng
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908 USA
| | - Matthew Orchard
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210 USA
| | - Harper Smith
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210 USA
- Biophysics graduate program, The Ohio State University, Columbus, OH 43210 USA
| | - Lucas A. Runyan
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210 USA
| | - Edward H. Egelman
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908 USA
| | - Dmitri S. Kudryashov
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210 USA
- Molecular Cellular and Developmental Biology graduate program, The Ohio State University, Columbus, OH 43210 USA
- Biophysics graduate program, The Ohio State University, Columbus, OH 43210 USA
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13
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Woida PJ, Satchell KJF. The Vibrio cholerae MARTX toxin silences the inflammatory response to cytoskeletal damage before inducing actin cytoskeleton collapse. Sci Signal 2020; 13:13/614/eaaw9447. [PMID: 31937566 DOI: 10.1126/scisignal.aaw9447] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Multifunctional autoprocessing repeats-in-toxin (MARTX) toxins are pore-forming bacterial toxins that translocate multiple functionally independent effector domains into a target eukaryotic cell. Vibrio cholerae colonizes intestinal epithelial cells (IECs) and uses a MARTX toxin with three effector domains-an actin cross-linking domain (ACD), a Rho inactivation domain (RID), and an α/β hydrolase domain (ABH)-to suppress innate immunity and enhance colonization. We investigated whether these multiple catalytic enzymes delivered from a single toxin functioned in a coordinated manner to suppress intestinal innate immunity. Using cultured human IECs, we demonstrated that ACD-induced cytoskeletal collapse activated extracellular signal-regulated kinase, p38, and c-Jun amino-terminal kinase mitogen-activated protein kinase (MAPK) signaling to elicit a robust proinflammatory response characterized by the secretion of interleukin-8 (IL-8; also called CXCL8) and the expression of CXCL8, tumor necrosis factor (TNF), and other proinflammatory genes. However, RID and ABH, which are naturally delivered together with ACD, blocked MAPK activation through Rac1 and thus prevented ACD-induced inflammation. RID also abolished IL-8 secretion induced by heat-killed bacteria, TNF, or latrunculin A. Thus, MARTX toxins use enzymatic multifunctionality to silence the host response to bacterial factors and to the damage caused by the toxins. Furthermore, these data show how V. cholerae MARTX toxin suppresses intestinal inflammation and contributes to cholera being classically defined as a noninflammatory diarrheal disease.
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Affiliation(s)
- Patrick J Woida
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Karla J F Satchell
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
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14
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Purde V, Busch F, Kudryashova E, Wysocki VH, Kudryashov DS. Oligomerization Affects the Ability of Human Cyclase-Associated Proteins 1 and 2 to Promote Actin Severing by Cofilins. Int J Mol Sci 2019; 20:E5647. [PMID: 31718088 PMCID: PMC6888645 DOI: 10.3390/ijms20225647] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 11/07/2019] [Accepted: 11/08/2019] [Indexed: 02/03/2023] Open
Abstract
Actin-depolymerizing factor (ADF)/cofilins accelerate actin turnover by severing aged actin filaments and promoting the dissociation of actin subunits. In the cell, ADF/cofilins are assisted by other proteins, among which cyclase-associated proteins 1 and 2 (CAP1,2) are particularly important. The N-terminal half of CAP has been shown to promote actin filament dynamics by enhancing ADF-/cofilin-mediated actin severing, while the central and C-terminal domains are involved in recharging the depolymerized ADP-G-actin/cofilin complexes with ATP and profilin. We analyzed the ability of the N-terminal fragments of human CAP1 and CAP2 to assist human isoforms of "muscle" (CFL2) and "non-muscle" (CFL1) cofilins in accelerating actin dynamics. By conducting bulk actin depolymerization assays and monitoring single-filament severing by total internal reflection fluorescence (TIRF) microscopy, we found that the N-terminal domains of both isoforms enhanced cofilin-mediated severing and depolymerization at similar rates. According to our analytical sedimentation and native mass spectrometry data, the N-terminal recombinant fragments of both human CAP isoforms form tetramers. Replacement of the original oligomerization domain of CAPs with artificial coiled-coil sequences of known oligomerization patterns showed that the activity of the proteins is directly proportional to the stoichiometry of their oligomerization; i.e., tetramers and trimers are more potent than dimers, which are more effective than monomers. Along with higher binding affinities of the higher-order oligomers to actin, this observation suggests that the mechanism of actin severing and depolymerization involves simultaneous or consequent and coordinated binding of more than one N-CAP domain to F-actin/cofilin complexes.
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Affiliation(s)
- Vedud Purde
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; (V.P.); (F.B.); (E.K.); (V.H.W.)
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
| | - Florian Busch
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; (V.P.); (F.B.); (E.K.); (V.H.W.)
- Resource for Native MS-Guided Structural Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Elena Kudryashova
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; (V.P.); (F.B.); (E.K.); (V.H.W.)
| | - Vicki H. Wysocki
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; (V.P.); (F.B.); (E.K.); (V.H.W.)
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
- Resource for Native MS-Guided Structural Biology, The Ohio State University, Columbus, OH 43210, USA
- Campus Chemical Instrument Center, Mass Spectrometry and Proteomics, The Ohio State University, Columbus, OH 43210, USA
| | - Dmitri S. Kudryashov
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; (V.P.); (F.B.); (E.K.); (V.H.W.)
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
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15
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Kufer TA, Creagh EM, Bryant CE. Guardians of the Cell: Effector-Triggered Immunity Steers Mammalian Immune Defense. Trends Immunol 2019; 40:939-951. [PMID: 31500957 DOI: 10.1016/j.it.2019.08.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 07/31/2019] [Accepted: 08/08/2019] [Indexed: 12/14/2022]
Abstract
The mammalian innate immune system deals with invading pathogens and stress by activating pattern-recognition receptors (PRRs) in the host. Initially proposed to be triggered by the discrimination of defined molecular signatures from pathogens rather than from self, it is now clear that PRRs can also be activated by endogenous ligands, bacterial metabolites and, following pathogen-induced alterations of cellular processes, changes in the F-actin cytoskeleton. These processes are collectively referred to as effector-triggered immunity (ETI). Here, we summarize the molecular and conceptual advances in our understanding of cell autonomous innate immune responses against bacterial pathogens, and discuss how classical activation of PRRs and ETI interplay to drive inflammatory responses.
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Affiliation(s)
- Thomas A Kufer
- Institute of Nutritional Medicine, Department of Immunology, University of Hohenheim, Stuttgart, Germany.
| | - Emma M Creagh
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland.
| | - Clare E Bryant
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK.
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16
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Dutta P, Jijumon AS, Mazumder M, Dileep D, Mukhopadhyay AK, Gourinath S, Maiti S. Presence of actin binding motif in VgrG-1 toxin of Vibrio cholerae reveals the molecular mechanism of actin cross-linking. Int J Biol Macromol 2019; 133:775-785. [PMID: 31002899 DOI: 10.1016/j.ijbiomac.2019.04.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 04/04/2019] [Accepted: 04/04/2019] [Indexed: 11/27/2022]
Abstract
Type VI secretion systems (T6SS) plays a crucial role in Vibrio cholerae mediated pathogenicity. Tip of T6SS is homologous to gp27/gp5 complex or tail spike of T4 bacteriophage. VgrG-1 of V. cholerae T6SS is unusual among other VgrG because its effector domain is trans-located into the cytosol of eukaryotic cells with an additional actin cross-linking domain (ACD) at its C terminal end. ACD of VgrG-1 (VgrG-1-ACD) causes T6SS dependent host cell cytotoxicity through actin cytoskeleton disruption to prevent bacterial engulfment by macrophages. ACD mediated actin cross-linking promotes survival of the bacteria in the small intestine of humans, along with other virulence factors; establishes successful infection with the onset of diarrhoea in humans. Our studies demonstrated VgrG-1-ACD can bind to actin besides actin cross-linking activity. Computational analysis of ACD revealed the presence of actin binding motif (ABM). Mutations in ABM lead to loss of actin binding in vitro. VgrG-1-ACD having the mutated ABM cannot cross-link actin efficiently in vitro and manifests less actin cytoskeleton disruption when transfected in HeLa cells.
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Affiliation(s)
- Priyanka Dutta
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, Nadia, West Bengal, India
| | - A S Jijumon
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, Nadia, West Bengal, India
| | | | - Drisya Dileep
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, Nadia, West Bengal, India
| | | | | | - Sankar Maiti
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, Nadia, West Bengal, India.
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17
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Varland S, Vandekerckhove J, Drazic A. Actin Post-translational Modifications: The Cinderella of Cytoskeletal Control. Trends Biochem Sci 2019; 44:502-516. [PMID: 30611609 DOI: 10.1016/j.tibs.2018.11.010] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Revised: 11/22/2018] [Accepted: 11/27/2018] [Indexed: 11/30/2022]
Abstract
Actin is one of the most abundant proteins in eukaryotic cells and the main component of the microfilament system. It plays essential roles in numerous cellular activities, including muscle contraction, maintenance of cell integrity, and motility, as well as transcriptional regulation. Besides interacting with various actin-binding proteins (ABPs), proper actin function is regulated by post-translational modifications (PTMs), such as acetylation, arginylation, oxidation, and others. Here, we explain how actin PTMs can contribute to filament formation and stability, and may have additional actin regulatory functions, which potentially contribute to disease development.
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Affiliation(s)
- Sylvia Varland
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, N-5020 Bergen, Norway; Department of Biological Sciences, University of Bergen, Thormøhlensgate 53 A, N-5020 Bergen, Norway; Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada
| | - Joël Vandekerckhove
- Department of Biochemistry, UGent Center for Medical Biotechnology, Ghent University, Albert Baertsoenkaai 3, 9000 Gent, Belgium
| | - Adrian Drazic
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, N-5020 Bergen, Norway.
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18
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Kim BS. The Modes of Action of MARTX Toxin Effector Domains. Toxins (Basel) 2018; 10:toxins10120507. [PMID: 30513802 PMCID: PMC6315884 DOI: 10.3390/toxins10120507] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 11/20/2018] [Accepted: 11/27/2018] [Indexed: 12/26/2022] Open
Abstract
Many Gram-negative bacterial pathogens directly deliver numerous effector proteins from the bacterium to the host cell, thereby altering the target cell physiology. The already well-characterized effector delivery systems are type III, type IV, and type VI secretion systems. Multifunctional autoprocessing repeats-in-toxin (MARTX) toxins are another effector delivery platform employed by some genera of Gram-negative bacteria. These single polypeptide exotoxins possess up to five effector domains in a modular fashion in their central regions. Upon binding to the host cell plasma membrane, MARTX toxins form a pore using amino- and carboxyl-terminal repeat-containing arms and translocate the effector domains into the cells. Consequently, MARTX toxins affect the integrity of the host cells and often induce cell death. Thus, they have been characterized as crucial virulence factors of certain human pathogens. This review covers how each of the MARTX toxin effector domains exhibits cytopathic and/or cytotoxic activities in cells, with their structural features revealed recently. In addition, future directions for the comprehensive understanding of MARTX toxin-mediated pathogenesis are discussed.
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Affiliation(s)
- Byoung Sik Kim
- Department of Food Science and Engineering, ELTEC College of Engineering, Ewha Womans University, Seoul 03760, Korea.
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