Involvement of a heptad repeat in the carboxyl terminus of the dihydropyridine receptor beta1a subunit in the mechanism of excitation-contraction coupling in skeletal muscle.

ABSTRACT: Chimeras consisting of the homologous skeletal dihydropyridine receptor (DHPR) beta1a subunit and the heterologous cardiac/brain beta2a subunit were used to determine which regions of beta1a were responsible for the skeletal-type excitation-contraction (EC) coupling phenotype. Chimeras were transiently transfected in beta1 knockout myotubes and then voltage-clamped with simultaneous measurement of confocal fluo-4 fluorescence. All chimeras expressed a similar density of DHPR charge movements, indicating that the membrane density of DHPR voltage sensors was not a confounding factor in these studies. The data indicates that a beta1a-specific domain present in the carboxyl terminus, namely the D5 region comprising the last 47 residues (beta1a 478-524), is essential for expression of skeletal-

SUBMITTER: Sheridan DC 

PROVIDER: S-EPMC1304501 | biostudies-literature | 2004 Aug

REPOSITORIES: biostudies-literature