Phosphorylation of moesin by rho-associated kinase (Rho-kinase) plays a crucial role in the formation of microvilli-like structures.
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.
Oshiro
N
N
Division of Signal Transduction, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma 630-0101, Japan.
Fukata
Y
Y
Kaibuchi
K
K
D000818:Animals; D019556:COS Cells; D019084:Fluorescent Antibody Technique, Indirect; D047908:Intracellular Signaling Peptides and Proteins; D051379:Mice; D008840:Microfilament Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D008871:Microvilli / Q000648:ultrastructure*; D010766:Phosphorylation; D010769:Phosphothreonine / Q000302:isolation & purification; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D013379:Substrate Specificity; D054460:rho-Associated Kinases
D047908:Intracellular Signaling Peptides and Proteins; D008840:Microfilament Proteins; D011994:Recombinant Proteins; D010769:Phosphothreonine; C071058:moesin; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases