Partial substitution of skeletal troponin C with cardiac troponin C in rabbit skeletal muscle fibers altered the Ca2+ dependence of tension development.
The type of troponin C present plays an important role in determining the Ca2+ dependence of tension development in striated muscle.
Binding of Ca2+ to the troponin C (TnC) subunit of troponin is necessary for tension development in skeletal and cardiac muscles. Tension was measured in skinned fibers from rabbit skeletal muscle at various Ca2+ before and after partial substitution of skeletal TnC with cardiac TnC. Following substitution, the tension-pCa relationship was altered in a manner consistent with the differences in the number of low-affinity Ca2+-binding sites on the two types of TnC and their affinities for Ca2+. The alterations in the tension-pCa relationship were for the most part reversed by reextraction of cardiac TnC and readdition of skeletal TnC into the fiber segments. These findings indicate that the type of TnC present plays an important role in determining the Ca2+ dependence of tension development in striated muscle.
Moss et al. (Thu,) reported a other. Partial substitution of skeletal TnC with cardiac TnC vs. Before substitution (skeletal TnC) was evaluated on Tension-pCa relationship (Ca2+ dependence of tension development). Partial substitution of skeletal troponin C with cardiac troponin C in rabbit skeletal muscle fibers altered the Ca2+ dependence of tension development.