Subunit Heterogeneity in N-type Ca Channels

• Published in: The Journal of biological chemistry 1996-02, Vol.271 (6), p.3207
• Main Authors: Victoria E. S. Scott, Michel De Waard, Hongyan Liu, Christina A. Gurnett, David P. Venzke, Vanda A. Lennon, Kevin P. Campbell
• Format: Article
• Language: English
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.271.6.3207

The β subunit of the voltage-dependent Ca channel is a cytoplasmic protein that interacts directly with an α subunit, thereby modulating the biophysical properties of the channel. Herein, we demonstrate that the α subunit of the N-type Ca channel associates with several different β subunits. Polyclonal antibodies specific for three different β subunits immunoprecipitated I- -conotoxin GVIA binding from solubilized rabbit brain membranes. Enrichment of the N-type Ca channels with an α subunit-specific monoclonal antibody showed the association of β , β , and β subunits. Protein sequencing of tryptic peptides of the 57-kDa component of the purified N-type Ca channel confirmed the presence of the β and β subunits. Each of the β subunits bound to the α subunit interaction domain with similar high affinity. Thus, our data demonstrate important heterogeneity in the β subunit composition of the N-type Ca channels, which may be responsible for some of the diverse kinetic properties recorded from neurons.