Promotes expression of the ion channel CACNA1H at the cell membrane, and thereby contributes to the regulation of channel activity (PubMed:27149520). Plays a minor and redundant role in promoting the expression of calcium channel CACNA1S at the cell membrane, and thereby contributes to increased channel activity (PubMed:29467163). Slows the rate of calcium-mediated inactivation of CACNA1C calcium channel activity (PubMed:29363593). Interacts (via SH3 domains) with CACNA1S (PubMed:29467163). Interacts with CACNA1H (PubMed:27149520). Interacts with CACNA1C (Probable) (PubMed:29363593). Expressed predominantly in brain (PubMed:8954993, PubMed:23818578) Detected in brain neurons, more specifically in hippocampus, cerebellum and inferior olive (PubMed:8954993). Highly expressed in urinary bladder, and detected at lower levels in adrenal gland (PubMed:23818578). Detected at very low levels in heart, liver, lung and kidney (PubMed:8954993). Expression in brain started at late 13.5 dpc and continued to adult (8W) with a peak around P10.