Inhibits calcium-dependent inactivation of L-type calcium channel and shifts voltage dependence of activation to more depolarized membrane potentials (By similarity). Involved in the transmission of light signals (By similarity). May positively regulate neurotransmitter vesicle endocytosis and exocytosis in a salt-dependent manner (By similarity). May play a role in the extension and network organization of neurites (By similarity). Interacts with CACNA1C (via C-terminal CDB motif) in a calcium-dependent manner (By similarity). Interacts with STXBP1 (PubMed:22039235). Interacts with MYO6 (PubMed:22039235). Expressed in the retina (at protein level).