Structure and functional expression of alpha 1, alpha 2, and beta subunits of a novel human neuronal calcium channel subtype.
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Williams ME, Feldman DH, McCue AF, Brenner R, Velicelebi G, Ellis SB, Harpold MM
Structure and functional expression of alpha 1, alpha 2, and beta subunits of a novel human neuronal calcium channel subtype.
Neuron. 1992 Jan;8(1):71-84.
- PubMed ID
- 1309651 [ View in PubMed]
- Abstract
The primary structures of human neuronal alpha 1, alpha 2, and beta subunits of a voltage-dependent Ca2+ channel were deduced by characterizing cDNAs. The alpha 1 subunit (alpha 1D) directs the recombinant expression of a dihydropyridine-sensitive L-type Ca2+ channel when coexpressed with the beta (beta 2) and the alpha 2 (alpha 2b) subunits in Xenopus oocytes. The recombinant channel is also reversibly blocked by 10-15 microM omega-conotoxin. Expression of the alpha 1D subunit alone, or coexpression with the alpha 2b subunit, did not elicit functional Ca2+ channel activity. Thus, the beta 2 subunit appears to serve an obligatory function, whereas the alpha 2b subunit appears to play an accessory role that potentiates expression of the channel. The primary transcripts encoding the alpha 1D, alpha 2, and beta subunits are differentially processed. At least two forms of neuronal alpha 1D were identified. Different forms of alpha 2 and beta transcripts were also identified in CNS, skeletal muscle, and aorta tissues.