Ca v β surface charged residues contribute to the regulation of neuronal calcium channels.

Voltage-gated calcium channels are essential regulators of brain function where they support depolarization-induced calcium entry into neurons. They consist of a pore-forming subunit (Ca v α 1 ) that requires co-assembly with ancillary subunits to ensure proper functioning of the channel. Among these ancillary subunits, the Ca v β plays an essential role in regulating surface expression and gating of the channels. This regulation requires the direct binding of Ca v β onto Ca v α 1 and is mediated by the alpha interacting domain (AID) within the Ca v α 1 subunit and the α binding pocket (ABP) within the Ca v β subunit. However, additional interactions between Ca v α 1 and Ca v β have been proposed. In this study, we analyzed the importance of Ca v β 3 surface charged residues in the regulation of Ca v 2.1 channels. Using alanine-scanning mutagenesis combined with electrophysiological recordings we identified several amino acids within the Ca v β 3 subunit that contribute to the gating of the channel. These findings add to the notion that additional contacts besides the main AID/ABP interaction may occur to fine-tune the expression and properties of the channel.