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 (PubMed:27822497). Expressed in the inner hair cells (IHCs), outer hair cells,(OHCs) and vestibular hair cells within the ear and in the retina (at protein level) (PubMed:28183797, PubMed:17947313). Expressed in the retinal cone type 6 ON-bipolar cells and type 1 OFF-bipolar cells (at protein level) (PubMed:27822497). Expressed in the organ of Corti and spiral ganglion neurons in the cochlea (at protein level) (PubMed:26809054). Mice exhibit synaptic hearing impairment and impaired auditory brainstem responses. Enhanced inactivation of Ca(2+) influx in inner hair cells (IHCs), whereas its amplitude and voltage dependence of activation is normal. Reduced normal spontaneous and sound-evoked firing of spiral ganglion neurons (SGNs) seen (PubMed:28183797). Mice exhibit normal retinal morphology but altered light responses of retinal ganglion cells (PubMed:27822497).