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Nat Cell Biol. 2015 Jul;17(7):880-92. doi: 10.1038/ncb3180. Epub 2015 Jun 8.

Molecular mechanism of vinculin activation and nanoscale spatial organization in focal adhesions.

Author information

1
Cell Biology and Physiology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.
2
National High Magnetic Field Laboratory and Department of Biological Science, The Florida State University, Tallahassee, Florida 32310, USA.
3
Howard Hughes Medical Institute, Janelia Farm Research Campus, Ashburn, Virginia 20147, USA.
4
Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA.

Abstract

Focal adhesions (FAs) link the extracellular matrix to the actin cytoskeleton to mediate cell adhesion, migration, mechanosensing and signalling. FAs have conserved nanoscale protein organization, suggesting that the position of proteins within FAs regulates their activity and function. Vinculin binds different FA proteins to mediate distinct cellular functions, but how vinculin's interactions are spatiotemporally organized within FAs is unknown. Using interferometric photoactivation localization super-resolution microscopy to assay vinculin nanoscale localization and a FRET biosensor to assay vinculin conformation, we found that upward repositioning within the FA during FA maturation facilitates vinculin activation and mechanical reinforcement of FAs. Inactive vinculin localizes to the lower integrin signalling layer in FAs by binding to phospho-paxillin. Talin binding activates vinculin and targets active vinculin higher in FAs where vinculin can engage retrograde actin flow. Thus, specific protein interactions are spatially segregated within FAs at the nanoscale to regulate vinculin activation and function.

PMID:
26053221
PMCID:
PMC4490039
DOI:
10.1038/ncb3180
[Indexed for MEDLINE]
Free PMC Article

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