Required for sound encoding at inner hair cells (IHCs) synapses, likely via inhibition of the inactivation of voltage-gated calcium channel of type 1.3 (Cav1.3) in the IHCs (PubMed:28183797). Required for the normal transfer of light signals through the retina (By similarity). {ECO:0000250|UniProtKB:Q9JLK4, ECO:0000269|PubMed:28183797}. This is the function of CABP2 (calcium binding protein 2, ENSG00000167791).