Traction forces of fibroblasts are regulated by the Rho-dependent kinase but not by the myosin light chain kinase

Arch Biochem Biophys. 2006 Dec 15;456(2):224-31. doi: 10.1016/ Epub 2006 Oct 11.


Adhesive cells show complex mechanical interactions with the substrate, however the exact mechanism of such interactions, termed traction forces, is still unclear. To address this question we have measured traction forces of fibroblasts treated with agents that affect the myosin II-dependent contractile mechanism. Using the potent myosin II inhibitor blebbistatin, we demonstrate that traction forces are strongly dependent on a functional myosin II heavy chain. Since myosin II is regulated by both the myosin light chain kinase (MLCK) and, directly or indirectly, the Rho-associated kinase (ROCK), we examined the effects of inhibitors against these kinases. Interestingly, inhibition of the myosin light chain kinase had no detectable effect, while inhibition of the Rho-dependent kinase caused strong inhibition of traction forces. Our results indicate that ROCK and MLCK play non-redundant roles in regulating myosin II functions, and that a subset of myosin II, regulated by the Rho small GTPase, may be responsible for the regulation of traction forces in migrating fibroblasts.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Cell Adhesion / drug effects
  • Cell Adhesion / physiology*
  • Homeostasis / physiology
  • Intracellular Signaling Peptides and Proteins / physiology*
  • Mechanotransduction, Cellular / drug effects
  • Mechanotransduction, Cellular / physiology*
  • Mice
  • Myosin Light Chains / physiology*
  • NIH 3T3 Cells
  • Phosphorylation
  • Protein-Serine-Threonine Kinases / physiology*
  • Stress, Mechanical
  • rho-Associated Kinases


  • Intracellular Signaling Peptides and Proteins
  • Myosin Light Chains
  • Protein-Serine-Threonine Kinases
  • rho-Associated Kinases