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 (PubMed:26680202). 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 (PubMed:26680202). Interacts with CACNA1C (PubMed:15141227). Interacts with RRAD. Interaction with RRAD regulates the trafficking of CACNA1C to the cell membrane (By similarity). Interacts with TMIGD2 (By similarity). Interacts with CAMK2D (PubMed:20194790). Interacts with CBARP (PubMed:24751537). Interacts with CAMK2A (By similarity). Highly expressed in heart and brain, and at lower levels in lung. Regulated through phosphorylation at Thr-549 by CaMK2D. Belongs to the calcium channel beta subunit family.