The β subunit of the voltage-dependent Ca2+ channel is a cytoplasmic protein that interacts directly with an α1 subunit, thereby modulating the biophysical properties of the channel. Herein, we demonstrate that the α1B subunit of the N-type Ca2+ channel associates with several different β subunits. Polyclonal antibodies specific for three different β subunits immunoprecipitated 125I-ω-conotoxin GVIA binding from solubilized rabbit brain membranes. Enrichment of the N-type Ca2+ channels with an α1B subunit-specific monoclonal antibody showed the association of β1b, β3, and β4 subunits. Protein sequencing of tryptic peptides of the 57-kDa component of the purified N-type Ca2+ channel confirmed the presence of the β3 and β4 subunits. Each of the β subunits bound to the α1B subunit interaction domain with similar high affinity. Thus, our data demonstrate important heterogeneity in the β subunit composition of the N-type Ca2+ channels, which may be responsible for some of the diverse kinetic properties recorded from neurons.
CITATION STYLE
Scott, V. E. S., De Waard, M., Liu, H., Gurnett, C. A., Venzke, D. P., Lennon, V. A., & Campbell, K. P. (1996). β subunit heterogeneity in N-type Ca2+ channels. Journal of Biological Chemistry, 271(6), 3207–3212. https://doi.org/10.1074/jbc.271.6.3207
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