Ca2+-sensitizing effects of the mutations at Ile-79 and Arg-92 of troponin T in hypertrophic cardiomyopathy

Sachio Morimoto, Fumi Yanaga, Reiko Minakami, Iwao Ohtsuki

Research output: Contribution to journalArticlepeer-review

101 Citations (Scopus)

Abstract

Several mutations in human cardiac troponin T (TnT) gene have been reported to cause hypertrophic cardiomyopathy (HCM). To explore the effects of the mutations on cardiac muscle contractile function under physiological conditions, human cardiac TnT mutants, Ile79Asn and Arg92Gln, as well as wild type, were expressed in Escherichia coli and exchanged into permeabilized rabbit cardiac muscle fibers, and Ca2+-activated force was determined. The free Ca2+ concentrations required for tension generation were found to be significantly lower in the mutant TnT-exchanged fibers than in the wild-type TnT-exchanged fibers, whereas no significant differences were found in tension-generating capability under maximal activating conditions and in cooperativity. These results suggest that a heightened Ca2+ sensitivity of cardiac muscle contraction is one of the factors to cause HCM associated with these TnT mutations.

Original languageEnglish
Pages (from-to)C200-C207
JournalAmerican Journal of Physiology - Cell Physiology
Volume275
Issue number1 44-1
DOIs
Publication statusPublished - Jul 1998

All Science Journal Classification (ASJC) codes

  • Physiology
  • Cell Biology

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