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Regulation of L-type Ca channel and phosphorylation

Research Project

Project/Area Number 09670044
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field General physiology
Research InstitutionHIROSHIMA UNIVERSITY

Principal Investigator

YAMAOKA Kaoru  Hiroshima University, Faculty of Medicine, Associate Professor, 医学部, 助教授 (10200586)

Project Period (FY) 1997 – 1998
Project Status Completed (Fiscal Year 1998)
Budget Amount *help
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 1998: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1997: ¥2,400,000 (Direct Cost: ¥2,400,000)
KeywordsL-type Ca channel / magnesium / calcium / phosphorylation / cardiac myocyte / cysteine / dorsal root ganglion / bull-frog / L型Caチャンネル / カエル
Research Abstract

The role of intracellular Mg^<2+> in the regulation of L-type Ca channel through A-kinase phosphorylation was elucidated using frog ventricular myocytes. When concentration of intracellular Mg^<2+> was lowered beyond a physiological level, it enhanced L-type Ca channel current (I_<Ca.L>) remarkably due to unblock of the channel from Mg^<2+>. The channel becomes insensitive to Mg^<2+> block when cell was phosphorylated through A-kinase stimulation. It concludes that phosphorylation regulates L-type Ca channel in cardiac myocytes through charging sensitivity to Mg^<2+> block. This particular type of Mg^<2+> block was not found in L-type Ca channel in frog dorsal root ganglion (DRG) neurons. The absence of Mg^<2+> block well correlates to the absence of the regulation through A-kinase in L-type Ca channel of frog DRG neurons. I have further found that membrane impermeable methanethiosulfonate compounds (MTS) that modify SH residues of cysteine can increase I_<Ca> dramatically from the intracellular side. This enhancing effect was not seen when I_<Ca> was pre-conditionally increased to a sub-maximal level by A-kinase stimulation. This indicates that MTS reagents affect one of the regulatory steps of phosphorylation mechanism. These results indicate that we may gain a further step to understand the mechanism of phosphorylation pathway if we target cysteines of intracellular region of L-type Ca channel or its associated proteins.

Report

(3 results)
  • 1998 Annual Research Report   Final Research Report Summary
  • 1997 Annual Research Report
  • Research Products

    (3 results)

All Other

All Publications (3 results)

  • [Publications] Yamaoka,K.: "Phosphorylation modulates L-type Ca channels in frog ventricular myocytes by changes in sensitivity to Mg2^+ block." Pflugers Arch - Eur J Physiol. 435. 329-337 (1998)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] Yamaoka, K.& Seyama, I.: "Phosphorylation modulates L-type Ca channels in frog ventricular myocytes by changes in sensitivity to Mg2+block." Pflugers Arch-Eur J Physiol. 435. 329-337 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] Yamaoka,K.: "Phosphorylation modulates L-type Ca channels in frog ventricular myocytes by changes in sensitivity to Mg^<2+> block." Pflugers Arch-Eur J Physiol. 435. 329-337 (1998)

    • Related Report
      1997 Annual Research Report

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Published: 1997-04-01   Modified: 2016-04-21  

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