Cardiac L-type Ca2+ channel triggers transmitter release in PC12 cells.
Among the various voltage-sensitive Ca2+ channels present in PC12 cells are the dihydropyridine (DHP)-sensitive L-channel, the omega-conotoxin (omega-CgTx)-sensitive N-channel, and an atypical omega-CgTx/DHP-insensitive Ca2+ channel. Depolarization-evoked Ca2+ entry and [3H]dopamine release is mediated by L-type Ca2+ channels determined by the use of Ca2+ channel antagonists, and a single protein of 250 kDa is recognized by L-type-specific antibodies. Screening of a PC12 cDNA library revealed two types of Ca2+ channels which were identified by partial sequencing. A pc12-L clone displayed virtually identical sequence homology to the cardiac L-type channel. The identical sequence homology of the single alternative splicing region confirmed clone pc12-L as the rbC-I transcript, a cardiac-neuronal alpha 1 subunit expressed in rat brain. Clone pc12-N displayed identical sequence homology to rbB-I, a neuronal alpha 1 subunit of the N-type Ca2+ channel expressed in rat brain; Northern blot analysis identified RNA of a size similar to that previously described for rat brain.
Avidor
B
B
Department of Biological Chemistry, Hebrew University of Jerusalem, Israel.
Avidor
T
T
Schwartz
L
L
De Jongh
K S
KS
Atlas
D
D
D000818:Animals; D001483:Base Sequence; D015220:Calcium Channels / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D020746:Calcium Channels, L-Type; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D004298:Dopamine / Q000378:metabolism*; D008969:Molecular Sequence Data; D009124:Muscle Proteins / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism*; D016716:PC12 Cells; D010455:Peptides / Q000494:pharmacology; D051381:Rats; D012689:Sequence Homology, Nucleic Acid; D013111:Spider Venoms / Q000494:pharmacology; D020867:omega-Agatoxin IVA; D020866:omega-Conotoxin GVIA
D015220:Calcium Channels; D020746:Calcium Channels, L-Type; D018076:DNA, Complementary; D009124:Muscle Proteins; D010455:Peptides; D013111:Spider Venoms; D020867:omega-Agatoxin IVA; D020866:omega-Conotoxin GVIA; D004298:Dopamine