Negatively regulates voltage-gated calcium channels by preventing the interaction between their alpha and beta subunits. Thereby, negatively regulates calcium channels activity at the plasma membrane and indirectly inhibits calcium-regulated exocytosis. Interacts with voltage-dependent calcium channels CACNB1, CACNB2, CACNB3 and CACNB4 beta subunits; prevents their interaction with the CACNA1C alpha subunit thereby negatively regulating the activity of the corresponding calcium channels. Expressed by neurons in the cortex, cerebellum and hippocampus and by pancreatic beta cells (at protein level). Detected in brain from 14 dpc until adulthood with higher expression between 18 dpc and P7 (at protein level). Probable cloning artifact.