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Alterations and significance of protein phosphatases, in particular of phosphatase IV, under diabetic conditions

Research Project

Project/Area Number 60480140
Research Category

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

Allocation TypeSingle-year Grants
Research Field Pathological medical chemistry
Research InstitutionTOHOKU UNIVERSITY

Principal Investigator

TSUIKI Shigeru  Research Institute for Tuberculosis and Cancer, Tohoku University - Professor, 抗酸菌病研究所, 教授 (90006065)

Co-Investigator(Kenkyū-buntansha) TAMURA Shinri  Research Institute for Tuberculosis and Cancer Tohoku University - Research Asso, 抗酸菌病研究所, 助手 (20124604)
KIKUCHI Kunimi  Research Institute for Tuberculosis and Cancer Tohoku University - Associate Pro, 抗酸菌病研究所, 助教授 (20006117)
Project Period (FY) 1985 – 1986
Project Status Completed (Fiscal Year 1986)
Budget Amount *help
¥6,600,000 (Direct Cost: ¥6,600,000)
Fiscal Year 1986: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1985: ¥5,100,000 (Direct Cost: ¥5,100,000)
KeywordsProtein phosphatase / Diabetes / Liver / Skeletal muscle / Glycogen synthase / グリコゲン / ホスホリラーゼ
Research Abstract

Previous studies indicated that protein phosphatase is a primary locus when diabetic conditions affect the carbohydrate- and lipid-metabolism of tissues. Liver and skeletal muscle, however, contain multiple species of protein phosphatase; and the fact that the dephosphorylation of glycogen synthase is more profoundly affceted than that of phosphorylase by diabetes suggests that only a particular species is tightly controlled by insulin. In rat liver, strong candidates are previously studied cytosolic phosphatase IA and newly discovered phosphatase IV, which is associated with the glycogen particles. Presently, the purification and characterization of phosphatase IV and the substrate specificity of phosphatase IA were studied.
Almost all the synthase phosphatase activity of rat liver particulate fraction is due to phosphatase IV, which, however, is unable to attack phosphorylase a. Its level is decreased by fasting, normalized by refeeding, and affected also by diabetes. After purification to electrophoretic homogeneity, the enzyme was still inhibited by glycogen and phosphorylase a. SDS-PAGE revealed phosphatase IV being monomeric with <M-r> =70K. Phosphatase IA, on the other hand, was first discovered as acting to liver synthase D preferentially. The enzyme was now found to be incapable of activating skeletal muscle synthase D. This suggests that phosphatase IA may be related to differentiated liver functions.

Report

(1 results)
  • 1986 Final Research Report Summary
  • Research Products

    (11 results)

All Other

All Publications (11 results)

  • [Publications] Shigeru Tsuiki: Advances in Protein Phosphatases. 1. 193-214 (1985)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1986 Final Research Report Summary
  • [Publications] Akira Hiraga: FEBS Letters. 205. 1-5 (1986)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1986 Final Research Report Summary
  • [Publications] Shinri Tamura: Biochemical and Biophysical Research Communications. 140. 212-218 (1986)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1986 Final Research Report Summary
  • [Publications] 立木蔚: 蛋白質核酸酵素. 31. 1940-1950 (1986)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1986 Final Research Report Summary
  • [Publications] Akira Hiraga: Journal of Biochemistry. 101. (1986)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1986 Final Research Report Summary
  • [Publications] Susumu Suzuki: Journal of Biological Chemistry. 262. (1987)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1986 Final Research Report Summary
  • [Publications] Shigeru Tsuiki: "Glycogen synthase phosphatase and phosphorylase phosphatase of rat liver" Advances in Protein Phopshatases. 1. 193-214 (1985)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1986 Final Research Report Summary
  • [Publications] Akira Hiraga: "Activation of a D-form of rabbit muscle glycogen synthase by <Ca^(2+)> - activated protease" FEBS Letters. 205. 1-5 (1986)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1986 Final Research Report Summary
  • [Publications] Shinri Tamura: "Identification and characterization of <Mg^(2+)> -dependent phosphotyrosyl protein phosphatase from rat liver cytosol" Biochemical and Biophysical Research Communications. 140. 212-218 (1986)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1986 Final Research Report Summary
  • [Publications] Akira Hiraga: "Activation of rat liver and rabbit skeletal muscle glycogen synthase by rat liver cytosolic protein phosphatases" Journal of Biochemistry. 101. (1987)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1986 Final Research Report Summary
  • [Publications] Susumu Suzuki: " <Mg^(++)> -ATP stimulates the generation of an insulin mediator from liver plasma membrane" Journal of Biological Chemistry. 262. (1987)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1986 Final Research Report Summary

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Published: 1987-03-31   Modified: 2016-04-21  

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