Ca2+ sensitization and potentiation of the maximum level of myofibrillar ATPase activity caused by mutations of troponin T found in familial hypertrophic cardiomyopathy

Fumi Yanaga, Sachio Morimoto, Iwao Ohtsuki

研究成果: ジャーナルへの寄稿学術誌査読

101 被引用数 (Scopus)

抄録

Human wild-type cardiac troponin T, I, C and five troponin T mutants (I79N, R92Q, F110I, E244D, and R278C) causing familial hypertrophic cardiomyopathy were expressed in Escherichia coli, and then were purified and incorporated into rabbit cardiac myofibrils using a troponin exchange technique. The Ca2+-sensitive ATPase activity of these myofibrillar preparations was measured in order to examine the functional consequences of these troponin mutations. An I79N troponin T mutation was found to cause a definite increase in Ca2+ sensitivity of the myofibrillar ATPase activity without inducing any significant change in the maximum level of ATPase activity. A detailed analysis indicated the inhibitory action of troponin I to be impaired by the I79N troponin T mutation. Two more troponin T mutations (R92Q and R278C) were also found to have a Ca2+-sensitizing effect without inducing any change in maximum ATPase activity. Two other troponin T mutations (F110I and E244D) had no Ca2+-sensitizing effects on the ATPase activity, but remarkably potentiated the maximum level of ATPase activity. These findings indicate that hypertrophic cardiomyopathy-linked troponin T mutations have at least two different effects on the Ca2+-sensitive ATPase activity, Ca2+-sensitization and potentiation of the maximum level of the ATPase activity.

本文言語英語
ページ(範囲)8806-8812
ページ数7
ジャーナルJournal of Biological Chemistry
274
13
DOI
出版ステータス出版済み - 3月 26 1999

!!!All Science Journal Classification (ASJC) codes

  • 生化学
  • 分子生物学
  • 細胞生物学

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