The beta subunit of voltage-dependent calcium channels contributes to the function of the calcium channel by increasing peak calcium current, shifting the voltage dependencies of activation and inactivation, modulating G protein inhibition and controlling the alpha-1 subunit membrane targeting. Component of a calcium channel complex consisting of a pore-forming alpha subunit (CACNA1S) and the ancillary subunits CACNB1 or CACNB2, CACNG1 and CACNA2D1. The channel complex contains alpha, beta, gamma and delta subunits in a 1:1:1:1 ratio, i.e. it contains either CACNB1 or CACNB2. Interacts with CACNA1C (By similarity). Interacts with RRAD. Interaction with RRAD regulates the trafficking of CACNA1C to the cell membrane. Interacts with TMIGD2 (By similarity). Interacts with CAMK2D (By similarity). Interacts with CBARP (PubMed:24751537). Interacts with CAMK2A (By similarity). Regulated through phosphorylation at Thr-549 by CaMK2D. Belongs to the calcium channel beta subunit family.