title: Vinculin-actin interaction couples actin retrograde flow to focal adhesions, but is dispensable for focal adhesion growth.
abstract: In migrating cells, integrin-based focal adhesions (FAs) assemble in protruding lamellipodia in association with rapid filamentous actin (F-actin) assembly and retrograde flow. How dynamic F-actin is coupled to FA is not known. We analyzed the role of vinculin in integrating F-actin and FA dynamics by vinculin gene disruption in primary fibroblasts. Vinculin slowed F-actin flow in maturing FA to establish a lamellipodium-lamellum border and generate high extracellular matrix (ECM) traction forces. In addition, vinculin promoted nascent FA formation and turnover in lamellipodia and inhibited the frequency and rate of FA maturation. Characterization of a vinculin point mutant that specifically disrupts F-actin binding showed that vinculin-F-actin interaction is critical for these functions. However, FA growth rate correlated with F-actin flow speed independently of vinculin. Thus, vinculin functions as a molecular clutch, organizing leading edge F-actin, generating ECM traction, and promoting FA formation and turnover, but vinculin is dispensible for FA growth.
authors.affiliation: Laboratory of Cell and Tissue Morphodynamics, Cell Biology and Physiology Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Ingo
authors.initials: I
authors.lastname: Thievessen
authors.forename: Peter M
authors.initials: PM
authors.lastname: Thompson
authors.forename: Sylvain
authors.initials: S
authors.lastname: Berlemont
authors.forename: Karen M
authors.initials: KM
authors.lastname: Plevock
authors.forename: Sergey V
authors.initials: SV
authors.lastname: Plotnikov
authors.forename: Alice
authors.initials: A
authors.lastname: Zemljic-Harpf
authors.forename: Robert S
authors.initials: RS
authors.lastname: Ross
authors.forename: Michael W
authors.initials: MW
authors.lastname: Davidson
authors.forename: Gaudenz
authors.initials: G
authors.lastname: Danuser
authors.forename: Sharon L
authors.initials: SL
authors.lastname: Campbell
authors.forename: Clare M
authors.initials: CM
authors.lastname: Waterman
mesh_terms: D000199:Actins / Q000378:metabolism*; D019943:Amino Acid Substitution; D000818:Animals; D002465:Cell Movement; D003001:Cloning, Molecular; D005109:Extracellular Matrix / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism; D022001:Focal Adhesions / Q000235:genetics / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D017354:Point Mutation; D011485:Protein Binding; D025941:Protein Interaction Mapping / Q000379:methods*; D021381:Protein Transport; D059748:Proteolysis; D011554:Pseudopodia / Q000378:metabolism; D016596:Vinculin / Q000235:genetics / Q000378:metabolism*
chemical_list: D000199:Actins; C485184:enhanced green fluorescent protein; D016596:Vinculin; D049452:Green Fluorescent Proteins