Interaction of calmodulin with troponin I and the troponin-tropomyosin-actin complex. Effect of Ca2+ or Sr2+ ions

K. Yamamoto, H. Nakayama, K. Nunoi, M. Fujishima

研究成果: Contribution to journalArticle査読

5 被引用数 (Scopus)

抄録

In an effort to elucidate the mechanism of calmodulin regulation of muscle contraction, we investigated the interaction between calmodulin and troponin components in the presence of Ca2+ or Sr2+ by the use of ultracentrifugation methods and polyacrylamide-gel electrophoresis. Skeletal-muscle troponin C bound to troponin I and dissociated it from the tropomyosin-actin complex in the presence of Ca2+ or Sr2+. When troponin T was absent, calmodulin bound to troponin I and dissociated it from the tropomyosin-actin complex in the presence of Ca2+ or Sr2+. When troponin T was present, calmodulin hardly bound to troponin I even in the presence of bivalent cations. Trifluoperazine, a calmodulin antagonist, inhibited the bivalent-cation-dependent interaction between calmodulin and troponin I. Calmodulin migrated more slowly in the presence of Sr2+ than it did in the presence of EGTA but faster than it did in the presence of Ca2+ on polyacrylamide-gel electrophoresis under non-denaturing conditions. It is concluded that troponin T is not required in the calmodulin regulation of muscle contraction because troponin T inhibits the bivalent-cation-dependent interaction between calmodulin and troponin I and because calmodulin binds to troponin I and dissociates it from the tropomyosin-actin complex in a bivalent-cation-dependent manner. Sr2+-induced exposure of the hydrophobic region enables calmodulin to bind to troponin I, as is the case with Ca2+.

本文言語英語
ページ(範囲)905-909
ページ数5
ジャーナルBiochemical Journal
241
3
DOI
出版ステータス出版済み - 1987
外部発表はい

All Science Journal Classification (ASJC) codes

  • 生化学
  • 分子生物学
  • 細胞生物学

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