Phosphorylation of moesin by rho-associated kinase (Rho-kinase) plays a crucial role in the formation of microvilli-like structures

J Biol Chem. 1998 Dec 25;273(52):34663-6. doi: 10.1074/jbc.273.52.34663.

Abstract

Rho-associated kinase (Rho-kinase), which is activated by the small GTPase Rho, phosphorylates moesin at Thr558 in vitro. Here, using a site- and phosphorylation state-specific antibody, we found that the expression of dominant active RhoA in COS7 cells induced moesin phosphorylation and the formation of microvilli-like structures at apical membranes where the Thr558-phosphorylated moesin accumulated, whereas the expression of dominant negative Rho-kinase inhibited both of these processes. The expression of dominant active Rho-kinase also induced moesin phosphorylation. When COS7 cells expressing moesin or moesinT558A (substitution of Thr by Ala) were cultured under serum-depleted conditions, there were few microvilli-like structures, whereas microvilli-like structures remained in the cells expressing moesinT558D (substitution of Thr by Asp). The expression of moesinT558A inhibited the dominant active RhoA-induced formation of microvilli-like structures. These results indicate that Rho-kinase regulates moesin phosphorylation downstream of Rho in vivo and that the phosphorylation of moesin by Rho-kinase plays a crucial role in the formation of microvilli-like structures.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • COS Cells
  • Fluorescent Antibody Technique, Indirect
  • Intracellular Signaling Peptides and Proteins
  • Mice
  • Microfilament Proteins / genetics
  • Microfilament Proteins / isolation & purification
  • Microfilament Proteins / metabolism*
  • Microvilli / ultrastructure*
  • Phosphorylation
  • Phosphothreonine / isolation & purification
  • Protein-Serine-Threonine Kinases / metabolism*
  • Recombinant Proteins / metabolism
  • Substrate Specificity
  • rho-Associated Kinases

Substances

  • Intracellular Signaling Peptides and Proteins
  • Microfilament Proteins
  • Recombinant Proteins
  • Phosphothreonine
  • moesin
  • Protein-Serine-Threonine Kinases
  • rho-Associated Kinases