γ-Actin regulates cell migration and modulates the ROCK signaling pathway

FASEB J. 2011 Dec;25(12):4423-33. doi: 10.1096/fj.11-185447. Epub 2011 Sep 9.

Abstract

Cell migration plays a crucial role in numerous cellular functions, and alterations in the regulation of cell migration are required for invasive transformation of a tumor cell. While the mechanistic process of actin-based migration has been well documented, little is known as to the specific function of the nonmuscle actin isoforms in mammalian cells. Here, we present a comprehensive examination of γ-actin's role in cell migration using an RNAi approach. The partial suppression of γ-actin expression in SH-EP neuroblastoma cells resulted in a significant decrease in wound healing and transwell migration. Similarly, the knockdown of γ-actin significantly reduced speed of motility and severely affected the cell's ability to explore, which was, in part, due to a loss of cell polarity. Moreover, there was a significant increase in the size and number of paxillin-containing focal adhesions, coupled with a significant decrease in phosphorylated paxillin in γ-actin-knockdown cells. In addition, there was a significant increase in the phosphorylation of cofilin and myosin regulatory light chain, suggesting an overactivated Rho-associated kinase (ROCK) signaling pathway in γ-actin-knockdown cells. The alterations in the phosphorylation of paxillin and myosin regulatory light chain were unique to γ-actin and not β-actin knockdown. Inhibition of the ROCK pathway with the inhibitor Y-27632 restored the ability of γ-actin-knockdown cells to migrate. This study demonstrates γ-actin as a potential upstream regulator of ROCK mediated cell migration.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / antagonists & inhibitors
  • Actins / genetics
  • Actins / metabolism*
  • Amides / pharmacology
  • Base Sequence
  • Cell Line
  • Cell Movement / physiology*
  • Cell Polarity / physiology
  • Focal Adhesions / physiology
  • Gene Knockdown Techniques
  • Humans
  • Models, Biological
  • Myosin Light Chains / metabolism
  • Paxillin / metabolism
  • Phosphorylation
  • Protein Kinase Inhibitors / pharmacology
  • Pyridines / pharmacology
  • RNA Interference
  • RNA, Small Interfering / genetics
  • Signal Transduction
  • Wound Healing / physiology
  • rho-Associated Kinases / metabolism*

Substances

  • Actins
  • Amides
  • Myosin Light Chains
  • Paxillin
  • Protein Kinase Inhibitors
  • Pyridines
  • RNA, Small Interfering
  • Y 27632
  • rho-Associated Kinases