Association of the myosin-binding subunit of myosin phosphatase and moesin: dual regulation of moesin phosphorylation by Rho-associated kinase and myosin phosphatase.
The small GTPase Rho is believed to regulate the actin cytoskeleton and cell adhesion through its specific targets. We previously identified the Rho targets: protein kinase N, Rho-associated kinase (Rho-kinase), and the myosin-binding subunit (MBS) of myosin phosphatase. We found that in MDCK epithelial cells, MBS accumulated at the tetradecanoylphorbol-13-acetate (TPA)-induced membrane ruffling area, where moesin, a member of the ERM (ezrin, radixin, and moesin) family, was localized. Neither membrane ruffling nor an accumulation of moesin and MBS at the free-end plasma membrane was induced when MDCK cells were stimulated with TPA after the microinjection of C3, which ADP-ribosylates and inactivates Rho. MBS was colocalized with moesin at the cell-cell contact sites in MDCK cells. We also found that moesin was coimmunoprecipitated with MBS from MDCK cells. Recombinant MBS interacted with the amino-terminal domains of moesin and ezrin. Myosin phosphatase composed of the catalytic subunit and MBS showed phosphatase activity toward moesin, which was phosphorylated by Rho-kinase. The phosphatase activity was inhibited when MBS was phosphorylated by Rho-kinase. These results suggest that MBS is recruited with moesin to the plasma membrane and that myosin phosphatase and Rho-kinase regulate the phosphorylation state of moesin downstream of Rho.
Fukata
Y
Y
Division of Signal Transduction, Nara Institute of Science and Technology, Ikoma 630-0101, Japan.
Kimura
K
K
Oshiro
N
N
Saya
H
H
Matsuura
Y
Y
Kaibuchi
K
K
D036002:ADP Ribose Transferases / Q000235:genetics / Q000502:physiology; D000818:Animals; D001905:Botulinum Toxins; D001921:Brain / Q000378:metabolism; D002417:Cattle; D002460:Cell Line; D002462:Cell Membrane / Q000737:chemistry / Q000201:enzymology / Q000648:ultrastructure; D002474:Cell-Free System; D003598:Cytoskeletal Proteins; D004285:Dogs; D004847:Epithelial Cells; D047908:Intracellular Signaling Peptides and Proteins; D008840:Microfilament Proteins; D043263:Myosin-Light-Chain Phosphatase; D009218:Myosins / Q000378:metabolism; D010749:Phosphoprotein Phosphatases / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011506:Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins; D015398:Signal Transduction / Q000502:physiology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D054460:rho-Associated Kinases; D000099149:Ezrin
D036002:ADP Ribose Transferases; D001905:Botulinum Toxins; D003598:Cytoskeletal Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008840:Microfilament Proteins; D043263:Myosin-Light-Chain Phosphatase; D009218:Myosins; D010749:Phosphoprotein Phosphatases; D010750:Phosphoproteins; D017346:Protein Serine-Threonine Kinases; D011506:Proteins; D011993:Recombinant Fusion Proteins; D013755:Tetradecanoylphorbol Acetate; D054460:rho-Associated Kinases; D000099149:Ezrin; C071058:moesin; C063007:exoenzyme C3, Clostridium botulinum