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Involvement of the β-subunit in the potassium access channel of the sodium pump

Research Project

Project/Area Number 10680623
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Functional biochemistry
Research InstitutionUniversity of Occupational and Environmental Health

Principal Investigator

KAWAMURA Masaru  Univ. of Occup. and Environ. Heal, School of Medicine, Professor, 医学部, 教授 (00049066)

Co-Investigator(Kenkyū-buntansha) KIATAZAWA Takashi  Univ. of Occup. and Environ. Heal, School of Medicine, Assistant Professor, 医学部, 助手 (90122845)
Project Period (FY) 1998 – 1999
Project Status Completed (Fiscal Year 1999)
Budget Amount *help
¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 1999: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1998: ¥1,700,000 (Direct Cost: ¥1,700,000)
Keywordssodium pump / β-subunit / disulfide-bond / chimera / pump current / ATPase / proton pump / oocyte / ジスルフィド結合
Research Abstract

The sodium pump composed of the α and β subunits, couples the hydrolysis of ATP to the translocation of NaィイD1+ィエD1 and KィイD1+ィエD1 across the cell membrane. How does the pump perform this translocation of cations and what structural domains of the pump are involved in this process? In this study we obtained the following results regarding these two problems.
1. The chimera (βLィイD21ィエD2HH) is constructed by replacing the first disulfide-bonded loop (LィイD21ィエD2) of the sodium pump by the corresponding loop of the gastric proton pump, resulting in the formation of a functionless complex with the α subunit of the sodium pump. The chimeras (βLィイD21ィエD2HN and βL1NH) are constructed by replacing each half of the LィイD21ィエD2 of βLィイD21ィエD2HH by the corresponding portion of the sodium pump β subunit, forming partially active complexes with the α subunit. The result suggests that the N-terminal and C-terminal halves of LィイD21ィエD2 of the sodium pump function independently of each other. The mutatio … More n of Phe148 to Arg in the βLィイD21ィエD2HH restored the activity to the same extent as βLィイD21ィエD2HN, indicating that Arg148 is a critical residue in the C-terminal half of LィイD21ィエD2 of the sodium pump. In the N-terminal half, PADY sequence seems to be important for the sodium pump.
2. Glu residues in transmembrane segments (Glu-334, -959 and -960) of the α subunit of the sodium pomp have been discussed as possible candidates for the binding sites of the transported cations. We demonstrated that none of the three Glu residues is essential for cation coordination, but that Glu-334, and in part also Glu-960, seems to be involved in preserving the ouabain-resistant conformation of the sodium pump.
3. Polytoxin converts the sodium pump into an ion channel. We studied the effect of truncation of the N-terminus of the sodium pump α subunit on channel properties and pump functions. The results suggest that the N-terminus is involved in a voltage-dependent gate of the channel structure inherent in the pump molecule. Less

Report

(3 results)
  • 1999 Annual Research Report   Final Research Report Summary
  • 1998 Annual Research Report
  • Research Products

    (13 results)

All Other

All Publications (13 results)

  • [Publications] Larisa A. Vasilets: "Significance of the glutamic acid residues Glu_<334>, Glu_<959>, and Glu_<960> of the α subunits of Torpedo Na^+, K^+ pumps for transport activity and ouabain binding"Biochimica et Biophysica Acta. 1368(1). 137-149 (1998)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] Shinji Asano: "Chimeric Domain Analysis of the Compatibility between H^+, K^+ -ATPase and Na^+, K^+ -ATPase β-Subunits for the Functional Expression of Gastric H^+, K^+ -ATPase"The Journal of Biological Chemistry. 274(32). 22257-22265 (1999)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] Kazuo Takeda: "Na/K pump and related pumps"ELSEVIER SCIENCE (ed. K. Taniguchi) (印刷中). (2000)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] Chau. H. Wu: "Na/K pump and related pumps"ELSEVIER SCIENCE (ed. K. Taniguchi) (印刷中). (2000)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] Larisa A. Vasilets: "Significance of the glutamic acid residues GluィイD2334ィエD2, GluィイD2959ィエD2, and GluィイD2960ィエD2 of the α subunits of Torpedo NaィイD1+ィエD1, KィイD1+ィエD1 pumps for transport activity and ouabain binding."Biochemical et Biophysica Acta. 1368. 137-149 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] Shinji, Asano: "Chimeric Domain Analysis of the Compatibility between HィイD1+ィエD1, KィイD1+ィエD1-ATPase and NaィイD1+ィエD1, KィイD1+ィエD1-ATPase β-Subunits for the Functional Expression of Gastric HィイD1+ィエD1, KィイD1+ィエD1-ATOase."Journal of Biological Chemistry. 274(32). 22257-22265 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] Kazuo Takeda: "Na/K pump and related pumps."ELSECVIER SCIENCE (ed. K. Taniguchi in press). (2000)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] Chau. H. Wu: "Na/K pump and related pumps."ELSECVIER SCIENCE (ed. K. Taniguchi in press). (2000)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] Larisa A.Vasilets: "Significance of the glutamic acid residues Glu_<334>,Glu_<959>,and Glu_<960> of the α subunits of Torpedo Na^+,K^+ pumps for transport activity and ouabain binding"Biochimica et Biophysica Acta. 1368(1). 137-149 (1998)

    • Related Report
      1999 Annual Research Report
  • [Publications] Shinji Asano: "Chimeric Domain Analysis of the Compatibility between H^+,K^+-ATPase and Na^+,K^+-ATPase β-Subunits for the Functional Expression of Gastric H^+,K^+-ATPase"The Journal of Biological Chemistry. 274(32). 22257-22265 (1999)

    • Related Report
      1999 Annual Research Report
  • [Publications] Kazuo Takeda: "Na/K pump and related pumps"ELSEVIER SCIENCE(ed.K.Taniguchi)(印刷中). (2000)

    • Related Report
      1999 Annual Research Report
  • [Publications] Chau.H.Wu: "Na/K pump and related pumps"ELSEVIER SCIENCE(ed.K.Taniguchi)(印刷中). (2000)

    • Related Report
      1999 Annual Research Report
  • [Publications] Larisa A.Vasilets: "Significance of the glutamic acid residues Glu_<334・> Glu_<959・> and Glu_<960> of the α subunits of Torpedo Na^+,K^+ pumps for transport activity and ouabain binding" Biochimica et Biophysica Acta. 1368(1). 137-149 (1998)

    • Related Report
      1998 Annual Research Report

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Published: 1998-04-01   Modified: 2016-04-21  

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