Exchanging native cardiac troponin C for purified skeletal TnC in Syrian hamster right ventricular muscle decreased Ca2+ sensitivity to 62% of its original value and increased thin-filament cooperativity.
The troponin C moiety regulates thin-filament cooperativity and Ca2+ sensitivity in cardiac muscle activation, with modifications associated with alterations in its primary structure.
Absolute Event Rate: 62% vs 100%
This study describes the effects of exchanging native cardiac troponin C (CTnC) from the right ventricular muscle of Syrian hamster for purified skeletal (S) TnC from fast twitch muscles in triggering cardiac contraction. Ca2+ sensitivity of the myocardium became decreased with STnC to 62% of the original value with CTnC. Furthermore, the slope of the pCa-force curve of cardiac muscle was found to be increased with STnC. The results show that the TnC moiety, as part of the switching mechanism during activation, also regulates thin-filament cooperativity in muscle. Modifications in both the Ca2+ sensitivity and cooperativity are associated with alterations in the primary structure of TnC.
Gulati et al. (Mon,) conducted a other in Cardiac muscle contraction. Purified skeletal (S) TnC from fast twitch muscles vs. Native cardiac troponin C (CTnC) was evaluated on Ca2+ sensitivity of the myocardium. Exchanging native cardiac troponin C for purified skeletal TnC in Syrian hamster right ventricular muscle decreased Ca2+ sensitivity to 62% of its original value and increased thin-filament cooperativity.