Elongation factor-1α is a novel substrate of Rho-associated kinase

Tetsuyuki Izawa, Yuko Fukata, Toshihide Kimura, Akihiro Iwamatsu, Kazuhiro Dohi, Kozo Kaibuchi

研究成果: ジャーナルへの寄稿学術論文査読

60 被引用数 (Scopus)


Rho-associated kinase (Rho-kinase), which is activated by the Rho small GTPase, phosphorylates the myosin-binding subunit (MBS) of myosin phosphatase, myosin light chain (MLC), the ERM family proteins, and adducin, thereby regulating the formation of stress fibers, focal adhesions, microvillus formation, and cell motility. Here, to further understand the role of Rho-kinase in the regulation of the numerous cellular processes by Rho, we purified a novel substrate of Rho-kinase having a molecular mass of 48 kDa (p48) from a rat liver cytosol extract. Mass spectral analysis revealed p48 to be elongation factor-1 alpha (EF-1α), which is known as an actin-binding protein besides a cofactor of polypeptide elongation. Rho-kinase directly phosphorylated recombinant EF-1α in vitro. A high-speed cosedimentation assay revealed that phosphorylation of EF-1α by Rho-kinase decreased the binding activity of EF-1α to filamentous actin (F-actin). A low-speed sedimentation assay revealed that phosphorylation of EF-1α by Rho-kinase decreased the F-actin-bundling activity. In addition, EF-1α bound to MBS of myosin phosphatase, suggesting that both Rho-kinase and myosin phosphatase regulate the phosphorylation state of EF-1α downstream of Rho as other substrates of Rho-kinase, i.e., MLC, adducin, and the ERM family. These results suggest that the Rho/Rho-kinase pathway regulates the organization of actin cytoskeleton via the phosphorylation of EF-1α. (C) 2000 Academic Press.

ジャーナルBiochemical and Biophysical Research Communications
出版ステータス出版済み - 11-11-2000

All Science Journal Classification (ASJC) codes

  • 生物理学
  • 生化学
  • 分子生物学
  • 細胞生物学


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