Altered regulation of cardiac muscle contraction by troponin T mutations that cause familial hypertrophic cardiomyopathy

Danuta Szczesna-Cordary, Ren Zhang, Jiaju Zhao, Michelle Jones, Georgianna Guzman, James D. Potter

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Abstract

To study the effect of troponin (Tn) T mutations that cause familial hypertrophic cardiomyopathy (FHC) on cardiac muscle contraction, wild-type, and the following recombinant human cardiac TnT mutants were cloned and expressed: I79N, R92Q, F110I, E163K, R278C, and intron 16(G1 → A) (In16). These TnT FHC mutants were reconstituted into skinned cardiac muscle preparations and characterized for their effect on maximal steady state force activation, inhibition, and the Ca2+ sensitivity of force development. Troponin complexes containing these mutants were tested for their ability to regulate actin-tropomyosin(Tm)-activated myosin-ATPase activity. TnT(R278C) and TnT(F110I) reconstituted preparations demonstrated dramatically increased Ca2+ sensitivity of force development, while those with TnT(R92Q) and TnT(I79N) showed a moderate increase. The deletion mutant, TnT(In16), significantly decreased both the activation and the inhibition of force, and substantially decreased the activation and the inhibition of actin-Tm- activated myosin-ATPase activity. ATPase activation was also impaired by TnT(F110I), while its inhibition was reduced by TnT(R278C). The TnT(E163K) mutation had the smallest effect on the Ca2+ sensitivity of force; however, it produced an elevated activation of the ATPase activity in reconstituted thin filaments. These observed changes in the Ca2+ regulation of force development caused by these mutations would likely cause altered contractility and contribute to the development of FHC.

Original languageEnglish
Pages (from-to)624-630
Number of pages7
JournalJournal of Biological Chemistry
Volume275
Issue number1
DOIs
StatePublished - Jan 7 2000

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Familial Hypertrophic Cardiomyopathy
Troponin T
Myosins
Muscle Contraction
Muscle
Myocardium
Chemical activation
Tropomyosin
Mutation
Adenosine Triphosphatases
Actins
Troponin
Introns

ASJC Scopus subject areas

  • Biochemistry

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Altered regulation of cardiac muscle contraction by troponin T mutations that cause familial hypertrophic cardiomyopathy. / Szczesna-Cordary, Danuta; Zhang, Ren; Zhao, Jiaju; Jones, Michelle; Guzman, Georgianna; Potter, James D.

In: Journal of Biological Chemistry, Vol. 275, No. 1, 07.01.2000, p. 624-630.

Research output: Contribution to journalArticle

Szczesna-Cordary, Danuta ; Zhang, Ren ; Zhao, Jiaju ; Jones, Michelle ; Guzman, Georgianna ; Potter, James D. / Altered regulation of cardiac muscle contraction by troponin T mutations that cause familial hypertrophic cardiomyopathy. In: Journal of Biological Chemistry. 2000 ; Vol. 275, No. 1. pp. 624-630.
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