Differential effect of actomyosin relaxation on the dynamic properties of focal adhesion proteins

PLoS One. 2013 Sep 9;8(9):e73549. doi: 10.1371/journal.pone.0073549. eCollection 2013.

Abstract

Treatment of cultured cells with inhibitors of actomyosin contractility induces rapid deterioration of stress fibers, and disassembly of the associated focal adhesions (FAs). In this study, we show that treatment with the Rho kinase inhibitor Y-27632, which blocks actomyosin contractility, induces disarray in the FA-associated actin bundles, followed by the differential dissociation of eight FA components from the adhesion sites. Live-cell microscopy indicated that the drug triggers rapid dissociation of VASP and zyxin from FAs (τ values of 7-8 min), followed by talin, paxillin and ILK (τ ~16 min), and then by FAK, vinculin and kindlin-2 (τ = 25-28 min). Examination of the molecular kinetics of the various FA constituents, using Fluorescence Recovery After Photobleaching (FRAP), in the absence of or following short-term treatment with the drug, revealed major changes in the kon and koff values of the different proteins tested, which are in close agreement with their differential dissociation rates from the adhesion sites. These findings indicate that mechanical, actomyosin-generated forces differentially regulate the molecular kinetics of individual FA-associated molecules, and thereby modulate FA composition and stability.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actin Cytoskeleton / drug effects
  • Actin Cytoskeleton / metabolism*
  • Actomyosin / antagonists & inhibitors
  • Actomyosin / metabolism*
  • Amides / pharmacology*
  • Animals
  • Cell Line
  • Focal Adhesions / drug effects
  • Focal Adhesions / metabolism*
  • Humans
  • Protein Kinase Inhibitors / pharmacology*
  • Pyridines / pharmacology*
  • Rats
  • rho-Associated Kinases / antagonists & inhibitors*

Substances

  • Amides
  • Protein Kinase Inhibitors
  • Pyridines
  • Y 27632
  • Actomyosin
  • rho-Associated Kinases