title: Diphosphorylation of regulatory light chain of myosin IIA is responsible for proper cell spreading.
abstract: The actomyosin cytoskeleton plays prominent roles in cell spreading and migration. To address the roles of myosin II isoforms and to estimate the region where the myosin IIs are activated in spreading cells, we examined the immunolocalization of myosin II isoforms and phosphorylated RLCs in the spreading MRC-5 cells. We observed the formation of actin ring-like structure at the base of the lamella. Both myosin IIA and IIB were predominantly localized there. Myosin IIA and diphosphorylated RLC were distributed outside of the region where myosin IIB and monophosphoryated RLC were distributed predominantly. Inhibition of Rho-kinase resulted in the disappearance of the diphosphorylation of RLC, moreover, it accelerated the rate of cell spreading and induced an aberrant cell shape at later stage of spreading. These results indicate that diphosphorylation of RLCs of myosin IIA by Rho-kinase in lamella is responsible for the cell to spread properly.
authors.affiliation: Hokkaido University, Kita-ku, Sapporo, Japan.
authors.forename: Naoya
authors.initials: N
authors.lastname: Hirata
authors.forename: Masayuki
authors.initials: M
authors.lastname: Takahashi
authors.forename: Michio
authors.initials: M
authors.lastname: Yazawa
mesh_terms: D002465:Cell Movement / Q000187:drug effects; D006801:Humans; D018994:Myosin Light Chains / Q000378:metabolism*; D024507:Nonmuscle Myosin Type IIA / Q000378:metabolism*; D024501:Nonmuscle Myosin Type IIB / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D054460:rho-Associated Kinases / Q000378:metabolism
chemical_list: D018994:Myosin Light Chains; D047428:Protein Kinase Inhibitors; D054460:rho-Associated Kinases; D024507:Nonmuscle Myosin Type IIA; D024501:Nonmuscle Myosin Type IIB