Regulatory subunit of the voltage-gated calcium channel that gives rise to L-type calcium currents (PubMed:1312465). Increases CACNA1B peak calcium current and shifts the voltage dependencies of channel activation and inactivation (By similarity). Increases CACNA1C peak calcium current and shifts the voltage dependencies of channel activation and inactivation (By similarity). Component of a calcium channel complex consisting of a pore-forming alpha subunit (CACNA1C) and the ancillary subunits CACNB3 and CACNA2D1 (PubMed:1312465). The channel complex contains alpha, beta, gamma and delta subunits in a 1:1:1:1 ratio. Interacts with CACNA2D4. Interacts with FASLG (By similarity). Interacts with CBARP; prevents the interaction of CACNB3 with the alpha subunit CACNA1C thereby negatively regulating the activity of the corresponding calcium channel (By similarity). Most abundant in brain but also present in aorta, trachea and lung. Belongs to the calcium channel beta subunit family.