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1993 Fiscal Year Final Research Report Summary

Analysis of signal transduction of insulin with special reference to protein kinase FA

Research Project

Project/Area Number 04454599
Research Category

Grant-in-Aid for General Scientific Research (B)

Allocation TypeSingle-year Grants
Research Field 代謝生物化学
Research InstitutionTokyo University

Principal Investigator

ENOMOTO Takemi  Tokyo University, Facul.of Pharmaceu.Sciences, Associate Professor, 薬学部, 助教授 (80107383)

Project Period (FY) 1992 – 1993
KeywordsInsulin / Protein kinase Fa / MAP kinase / Swiss 3T3 / thrombin / GTP binding protein / PI-3 kinase
Research Abstract

Protein kinase FA(PKFA) is a serine/threonine kinase, which was originally discovered as the factor necessary to convert inactive phoshatase 1 to active form. Binding of insulin to its receptor stimulates the tyrosine kinase activity of the insulin receptor and leads to increased serine/threonine phosphorylation of many cellular proteins and decreased phosphorylation of other proteins. In order to clarify the mechanism of signal transduction of insulin, I studied PKFA, expecting that PKFA is a key enzyme which connects the activation of tyrosine kinase with increased serine/threonine phosphorylation and dephosphorylation of proteins in the cells stimulated by insulin. First, I tried to establish an assay system for PKFA activity and then, examined activation of PKFA and translocation of the enzyme from the plasma membrane to the cytosol after stimulation by insulin. However, I could not observe activation of the enzyme nor translocation of the enzyme in all systems that I examined. Thu … More s, I changed the target from PKFA to mitogen activated protein (MAP) kinase which is converted to active from by phosphorylation of tyrosine and threonine, and studied the mechanism of signal transduction leading to the activation of MAP kinase in Swiss 3T3 cells.
Treatment of quiescent Swiss 3T3 cells with EGF resulted in the increase in the protein kinase activity that phosphorylated myelin basic protein, making a peak 2.5 min after the treatment. This kinase activity was identified as MAP kinase by FPLC Mono Q column chromatography. The increase in MAP kinase activity was also observed with phorbolester, thrombin, and bradykinin, and the increase in the kinase activity correlated well with the induction of DNA synthesis. I examined the mechanism of signal transduction from treatment of thrombin to the activation of MAP kinase in detail and confirmed the involvement of GTP binding protein, PI-3 kinase, and C kinase in the pathway to the activation of MAP kinase, In addition, the phosphorylation of DNA topoisomerase II was studied as one of final target of phosphorylation cascade. Less

  • Research Products

    (6 results)

All Other

All Publications (6 results)

  • [Publications] Saijo,M.: "Growth state and cell cycle dependent phosphorylation of DNA topoisomerase II in Swiss 3T3 cells." Biochemistry. 31. 359-363 (1992)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Enomoto,T.: "Cell cycle-dependent phosphorylation of topoisomerase II and modification of its activity by phosphorylation." Molecular biology of DNA topoisomerases and its application to chemotherapy. 65-75 (1993)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Kimura,K.: "Growth state- and cell cycle-dependent fluctuation in the expression of two forms of DNA topoisomerase II and possible specific modification of the higher molecular weight form." Journal of Biological chemistry. 269. 1173-1176 (1994)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Saijo, M., Ui, M.and Enomoto, T.: "Growth State and cell cycle dependent phosphorylation of DNA topoisomerase II in Swiss 3T3 cells." Biochemistry. 31. 359-363 (1992)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Enomoto, T., Saijo, M., Kimura, K.and Ui, M.: "Cell cycle-dependent phosphorylation of topoisomerase II and modification of its activity by phosphorylation." Mol.Biol.of DNA Topo.II and Its Appli.to Chemothr.65-75 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Kimura, K., Saijo, M., Ui, M.and Enomoto, T.: "Growth state- and cell cycle-dependent fluctuation in the expression of two forms of DNA topoisomerase II and possible specific modification of the higher molecular weight form." J.Biol.Chem.269. 1173-1176 (1994)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 1995-03-27  

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