Protein Chemistry and Structure
Identification of Three Subunits of the High Affinity ω-Conotoxin MVIIC-sensitive Ca2+ Channel*

https://doi.org/10.1074/jbc.271.23.13804Get rights and content
Under a Creative Commons license
open access

N-, P- and Q-type voltage-dependent Ca2+ channels control neurotransmitter release in the nervous system and are blocked by ω-conotoxin MVIIC. In this study, both a high affinity and a low affinity binding site for ω-conotoxin MVIIC were detected in rabbit brain. The low affinity binding site is shown to be present on the N-type Ca2+ channel. Using optimized conditions for specific labeling of the high affinity ω-conotoxin MVIIC receptor and a panel of subunit specific antibodies, the molecular structure of the high affinity receptor was investigated. We demonstrate for the first time that this receptor is composed of at least α1A, α2δ, and any one of the four brain β subunits. Such association of different β subunits with α1A and α2δ components may produce Ca2+ channels with distinct functional properties, such as P- and Q-type.

Cited by (0)

*

The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

Supported by American Heart Association-Iowa Affiliate Predoctoral Fellowship.

Supported by National Institutes of Health, NCI Grant CA-37343.