PRIMARY STRUCTURE OF THE GAMMA-SUBUNIT OF THE DHP-SENSITIVE CALCIUM-CHANNEL FROM SKELETAL-MUSCLE

Affinity-purified, polyclonal antibodies to the γ subunit of the dihydropyridine (DHP)-sensitive, voltage-dependent calcium channel have been used to isolate complementary DNAs to the rabbit skeletal muscle protein from an expression library. The deduced primary structure indicates that the γ subunit is a 25,058-dalton protein that contains four transmembrane domains and two N-linked glycosylation sites, consistent with biochemical analyses showing that the γ subunit is a glycosylated hydrophobic protein. Nucleic acid hybridization studies indicate that there is a 1200-nucleotide transcript in skeletal muscle but not in brain or heart. The γ subunit may play a role in assembly, modulation, or the structure of the skeletal muscle calcium channel.