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Science. 2017 Aug 18;357(6352):703-706. doi: 10.1126/science.aan2556.

Vinculin forms a directionally asymmetric catch bond with F-actin.

Author information

1
Biophysics Program, Stanford University, Stanford, CA 94305, USA.
2
Department of Structural Biology, Stanford University, Stanford, CA 94305, USA.
3
Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA.
4
Biophysics Program, Stanford University, Stanford, CA 94305, USA. bill.weis@stanford.edu alex.dunn@stanford.edu.
5
Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA.
6
Stanford Cardiovascular Institute, Stanford University, Stanford, CA 94305, USA.

Abstract

Vinculin is an actin-binding protein thought to reinforce cell-cell and cell-matrix adhesions. However, how mechanical load affects the vinculin-F-actin bond is unclear. Using a single-molecule optical trap assay, we found that vinculin forms a force-dependent catch bond with F-actin through its tail domain, but with lifetimes that depend strongly on the direction of the applied force. Force toward the pointed (-) end of the actin filament resulted in a bond that was maximally stable at 8 piconewtons, with a mean lifetime (12 seconds) 10 times as long as the mean lifetime when force was applied toward the barbed (+) end. A computational model of lamellipodial actin dynamics suggests that the directionality of the vinculin-F-actin bond could establish long-range order in the actin cytoskeleton. The directional and force-stabilized binding of vinculin to F-actin may be a mechanism by which adhesion complexes maintain front-rear asymmetry in migrating cells.

PMID:
28818948
PMCID:
PMC5821505
DOI:
10.1126/science.aan2556
[Indexed for MEDLINE]
Free PMC Article

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