Primary structure and functional expression of the omega-conotoxin-sensitive N-type calcium channel from rabbit brain.
The complete amino acid sequence of a rabbit brain calcium channel (BIII) has been deduced by cloning and sequencing the cDNA. The open reading frame encodes 2339 amino acids, which corresponds to an M(r) of 261,167. A phylogenetic tree representing evolutionary relationships indicates that BIII is grouped together with the other rabbit brain calcium channels, BI and BII, into a subfamily that is distinct from the dihydropyridine-sensitive L-type subfamily. Transient expression in cultured skeletal muscle myotubes derived from muscular dysgenic mice demonstrates that the BIII channel mediates an omega-conotoxin-sensitive calcium current with kinetics and voltage dependence like those previously reported for whole-cell N-type current. Cell-attached patch recordings, with isotonic barium as the charge carrier, revealed distinct single channels with an average slope conductance of 14.3 pS.
Department of Medical Chemistry, Kyoto University Faculty of Medicine, Japan.
Y
Y
Fujita
M
M
Mynlieff
R T
RT
Dirksen
M S
MS
Kim
T
T
Niidome
J
J
Nakai
T
T
Friedrich
N
N
Iwabe
T
T
Miyata
T
T
Furuichi
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D001921:Brain / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D006651:Histocytochemistry; D017403:In Situ Hybridization; D008969:Molecular Sequence Data; D010456:Peptides, Cyclic / Q000494:pharmacology*; D011817:Rabbits; D014018:Tissue Distribution; D020960:omega-Conotoxins
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D010456:Peptides, Cyclic; D020960:omega-Conotoxins; C053423:Conus magus toxin