title: How vinculin regulates force transmission.
abstract: Focal adhesions mediate force transfer between ECM-integrin complexes and the cytoskeleton. Although vinculin has been implicated in force transmission, few direct measurements have been made, and there is little mechanistic insight. Using vinculin-null cells expressing vinculin mutants, we demonstrate that vinculin is not required for transmission of adhesive and traction forces but is necessary for myosin contractility-dependent adhesion strength and traction force and for the coupling of cell area and traction force. Adhesion strength and traction forces depend differentially on vinculin head (V(H)) and tail domains. V(H) enhances adhesion strength by increasing ECM-bound integrin-talin complexes, independently from interactions with vinculin tail ligands and contractility. A full-length, autoinhibition-deficient mutant (T12) increases adhesion strength compared with VH, implying roles for both vinculin activation and the actin-binding tail. In contrast to adhesion strength, vinculin-dependent traction forces absolutely require a full-length and activated molecule; V(H) has no effect. Physical linkage of the head and tail domains is required for maximal force responses. Residence times of vinculin in focal adhesions, but not T12 or V(H), correlate with applied force, supporting a mechanosensitive model for vinculin activation in which forces stabilize vinculin's active conformation to promote force transfer.
authors.affiliation: Woodruff School of Mechanical Engineering, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA.
authors.forename: David W
authors.initials: DW
authors.lastname: Dumbauld
authors.forename: Ted T
authors.initials: TT
authors.lastname: Lee
authors.forename: Ankur
authors.initials: A
authors.lastname: Singh
authors.forename: Jan
authors.initials: J
authors.lastname: Scrimgeour
authors.forename: Charles A
authors.initials: CA
authors.lastname: Gersbach
authors.forename: Evan A
authors.initials: EA
authors.lastname: Zamir
authors.forename: Jianping
authors.initials: J
authors.lastname: Fu
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Chen
authors.forename: Jennifer E
authors.initials: JE
authors.lastname: Curtis
authors.forename: Susan W
authors.initials: SW
authors.lastname: Craig
authors.forename: Andrés J
authors.initials: AJ
authors.lastname: García
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D003599:Cytoskeleton / Q000378:metabolism*; D004622:Embryo, Mammalian / Q000166:cytology; D005109:Extracellular Matrix / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D036681:Fluorescence Recovery After Photobleaching; D022001:Focal Adhesions / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D016023:Integrins / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D008856:Microscopy, Fluorescence; D008954:Models, Biological; D011485:Protein Binding; D013314:Stress, Mechanical; D016608:Talin / Q000378:metabolism; D016596:Vinculin / Q000235:genetics / Q000378:metabolism*
chemical_list: D000199:Actins; D016023:Integrins; D016608:Talin; D016596:Vinculin; D049452:Green Fluorescent Proteins
keywords: cell adhesion; fibronectin