Phosphorylation of Vimentin by Rho-associated Kinase at a Unique Amino-terminal Site That Is Specifically Phosphorylated during Cytokinesis

• Published in: The Journal of biological chemistry 1998-05, Vol.273 (19), p.11728-11736
• Main Authors: Goto, H, Kosako, H, Tanabe, K, Yanagida, M, Sakurai, M, Amano, M, Kaibuchi, K, Inagaki, M
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Anaphase; Animals; Cattle; Cell Division; COS Cells; Fluorescent Antibody Technique, Indirect; GTP-Binding Proteins - metabolism; Guanosine Triphosphate - metabolism; Immunologic Techniques; Intermediate Filaments - ultrastructure; Intracellular Signaling Peptides and Proteins; Microscopy, Confocal; Molecular Sequence Data; Phosphorylation; Phosphoserine - metabolism; Protein-Serine-Threonine Kinases - metabolism; rho GTP-Binding Proteins; rho-Associated Kinases; Vimentin - metabolism
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.273.19.11728

We found that vimentin, the most widely expressed intermediate filament protein, served as an excellent substrate for Rho-associated kinase (Rho-kinase) and that vimentin phosphorylated by Rho-kinase lost its ability to form filaments in vitro . Two amino-terminal sites on vimentin, Ser 38 and Ser 71 , were identified as the major phosphorylation sites for Rho-kinase, and Ser 71 was the most favored and unique phosphorylation site for Rho-kinase in vitro . To analyze the vimentin phosphorylation by Rho-kinase in vivo , we prepared an antibody GK71 that specifically recognizes the phosphorylation of vimentin-Ser 71 . Ectopic expression of constitutively active Rho-kinase in COS-7 cells induced phosphorylation of vimentin at Ser 71 , followed by the reorganization of vimentin filament networks. During the cell cycle, the phosphorylation of vimentin-Ser 71 occurred only at the cleavage furrow in late mitotic cells but not in interphase or early mitotic cells. This cleavage furrow-specific phosphorylation of vimentin-Ser 71 was observed in the various types of cells we examined. All these accumulating observations increase the possibility that Rho-kinase may have a definite role in governing regulatory processes in assembly-disassembly and turnover of vimentin filaments at the cleavage furrow during cytokinesis.