title: Identification of an actin binding surface on vinculin that mediates mechanical cell and focal adhesion properties.
abstract: Vinculin, a cytoskeletal scaffold protein essential for embryogenesis and cardiovascular function, localizes to focal adhesions and adherens junctions, connecting cell surface receptors to the actin cytoskeleton. While vinculin interacts with many adhesion proteins, its interaction with filamentous actin regulates cell morphology, motility, and mechanotransduction. Disruption of this interaction lowers cell traction forces and enhances actin flow rates. Although a model for the vinculin:actin complex exists, we recently identified actin-binding deficient mutants of vinculin outside sites predicted to bind actin and developed an alternative model to better define this actin-binding surface, using negative-stain electron microscopy (EM), discrete molecular dynamics, and mutagenesis. Actin-binding deficient vinculin variants expressed in vinculin knockout fibroblasts fail to rescue cell-spreading defects and reduce cellular response to external force. These findings highlight the importance of this actin-binding surface and provide the molecular basis for elucidating additional roles of this interaction, including actin-induced conformational changes that promote actin bundling.
authors.affiliation: Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Molecular and Cellular Biophysics Program, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
authors.forename: Peter M
authors.initials: PM
authors.lastname: Thompson
authors.affiliation: Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
authors.forename: Caitlin E
authors.initials: CE
authors.lastname: Tolbert
authors.affiliation: Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
authors.forename: Kai
authors.initials: K
authors.lastname: Shen
authors.affiliation: Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Molecular and Cellular Biophysics Program, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
authors.forename: Pradeep
authors.initials: P
authors.lastname: Kota
authors.affiliation: Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Molecular and Cellular Biophysics Program, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
authors.forename: Sean M
authors.initials: SM
authors.lastname: Palmer
authors.affiliation: Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Molecular and Cellular Biophysics Program, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
authors.forename: Karen M
authors.initials: KM
authors.lastname: Plevock
authors.affiliation: Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908, USA.
authors.forename: Albina
authors.initials: A
authors.lastname: Orlova
authors.affiliation: Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908, USA.
authors.forename: Vitold E
authors.initials: VE
authors.lastname: Galkin
authors.affiliation: Department of Cell Biology and Physiology, 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.
authors.forename: Keith
authors.initials: K
authors.lastname: Burridge
authors.affiliation: Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908, USA.
authors.forename: Edward H
authors.initials: EH
authors.lastname: Egelman
authors.affiliation: Department of Biochemistry and Biophysics, 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.
authors.forename: Nikolay V
authors.initials: NV
authors.lastname: Dokholyan
authors.affiliation: Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
authors.forename: Richard
authors.initials: R
authors.lastname: Superfine
authors.affiliation: Department of Biochemistry and Biophysics, 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. Electronic address: campbesl@med.unc.edu.
authors.forename: Sharon L
authors.initials: SL
authors.lastname: Campbell
mesh_terms: D000199:Actins / Q000378:metabolism*; D000818:Animals; D030161:Avian Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D002478:Cells, Cultured; D005347:Fibroblasts / Q000166:cytology; D022001:Focal Adhesions; D057927:Hydrophobic and Hydrophilic Interactions; D051379:Mice; D008854:Microscopy, Electron / Q000379:methods; D008958:Models, Molecular; D017354:Point Mutation; D011817:Rabbits; D016596:Vinculin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
chemical_list: D000199:Actins; D030161:Avian Proteins; C035689:VCL protein, Gallus gallus; D016596:Vinculin