The C-terminal one-fourth of the skeletal muscle Ca2+ release channel (RyR1) has a major role in Ca2+ activation and inactivation.
The C-terminal region of the skeletal muscle ryanodine receptor (RyR1) plays a critical role in its calcium-dependent activation and inactivation.
Six chimeras of the skeletal muscle (RyR1) and cardiac muscle (RyR2) Ca(2+) release channels (ryanodine receptors) previously used to identify RyR1 dihydropyridine receptor interactions Nakai et al. (1998) J. Biol. Chem. 273, 13403 were expressed in HEK293 cells to assess their Ca(2+) dependence in (3)Hryanodine binding and single channel measurements. The results indicate that the C-terminal one-fourth has a major role in Ca(2+) activation and inactivation of RyR1. Further, our results show that replacement of RyR1 regions with corresponding RyR2 regions can result in loss and/or reduction of (3)Hryanodine binding affinity while maintaining channel activity.
Nakai et al. (1999) studied this question. Chimeras of skeletal muscle (RyR1) and cardiac muscle (RyR2) Ca2+ release channels was evaluated on Ca2+ dependence in [3H]ryanodine binding and single channel measurements. The C-terminal one-fourth of the skeletal muscle Ca2+ release channel (RyR1) has a major role in Ca2+ activation and inactivation.