Cloning and tissue-specific expression of the brain calcium channel beta-subunit.
A cDNA clone encoding a protein with high homology to the beta-subunit of the rabbit skeletal muscle dihydropyridine-sensitive calcium channel was isolated from a rat brain cDNA library. This rat brain beta-subunit cDNA hybridizes to a 3.4 kb message that is expressed in high levels in the cerebral hemispheres and hippocampus but is significantly reduced in cerebellum. The open reading frame encodes 597 amino acids with a predicted mass of 65 679 Da which is 82% homologous with the skeletal muscle beta-subunit. The brain cDNA encodes a unique 153 amino acid C-terminus and predicts the absence of a muscle-specific 50 amino acid internal segment. It also encodes numerous consensus phosphorylation sites suggesting a role in calcium channel regulation. The corresponding human beta-subunit gene was localized to chromosome 17. Hence the encoded brain beta-subunit, which has a primary structure highly similar to its isoform in skeletal muscle, may have a comparable role as an integral regulatory component of a neuronal calcium channel.
Pragnell
M
M
Howard Hughes Medical Institute, Program in Neuroscience, University of Iowa College of Medicine, Iowa City 52242.
Sakamoto
J
J
Jay
S D
SD
Campbell
K P
KP
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001923:Brain Chemistry; D015220:Calcium Channels / Q000378:metabolism*; D003001:Cloning, Molecular; D006224:Cricetinae; D004095:Dihydropyridines / Q000378:metabolism; D015870:Gene Expression; D006801:Humans; D008969:Molecular Sequence Data; D011817:Rabbits; D051381:Rats; D011978:Receptors, Nicotinic / Q000235:genetics* / Q000302:isolation & purification; D012689:Sequence Homology, Nucleic Acid; D012756:Sheep
D015220:Calcium Channels; D004095:Dihydropyridines; D011978:Receptors, Nicotinic; C038806:1,4-dihydropyridine