Involved in hearing and vision as member of the USH2 complex (PubMed:20502675). In the inner ear, required for the maintenance of hair bundle ankle formation, which connects growing stereocilia in developing cochlear hair cells (PubMed:20502675, PubMed:24334608). In retina photoreceptors, the USH2 complex is required for the maintenance of periciliary membrane complex that seems to play a role in regulating intracellular protein transport (PubMed:20502675). Interacts with collagen IV and fibronectin via its laminin EGF-like domains. Interaction with collagen may be required for stable integration into the basement membrane. Interacts with NINL (By similarity). Interacts with USH1C (PubMed:16301217). Component of USH2 complex, composed of ADGRV1, PDZD7, USH2A and WHRN (PubMed:20502675, PubMed:25406310). Interacts with ADGRV1/MASS1 (via N-terminal PDZ domain) (PubMed:20502675). Interacts (via the cytoplasmic region) with WHRN (PubMed:16301217, PubMed:20502675, PubMed:23055499). Interacts (via the cytoplasmic region) with PDZD7 (PubMed:23055499). Interacts (via the cytoplasmic region) with VEZT and MYO7A (via MyTH4-FERM domains); the interaction associates VEZT with the USH2 complex at the stereocilia base (PubMed:17567809). Component of the interstereocilia ankle links in the inner ear sensory cells (PubMed:20502675, PubMed:24334608). In photoreceptors, localizes at a plasma membrane microdomain in the apical inner segment that surrounds the connecting cilia called periciliary membrane complex (PubMed:20502675, PubMed:24334608). Present in the testis, epididymis, oviduct, spleen, submaxillary gland, and small and large intestines. Not detected in the brain, skin, lung, skeletal muscle, cardiac muscle, liver or kidney. Expressed in smooth muscle of the colon and the epididymis. Also present in select vascular basement membranes. In the cochlea, it is present in virtually every basement membrane. It is particularly high in the strial capillary basement membranes (SCBMs). In the retina, it is again expressed in all of the basement membranes. It is also very prevalent in the lens capsule and the Bruch's layer between the retinal pigment epithelium and the choroid layer, which is very rich in basement membranes. In neonates in it is widely expressed in the basement membranes of the cochlea. Present in the synaptic terminals of retinal photoreceptors (at protein level). The PDZ-binding motif mediates the association with some of the PDZ domains of USH1C and WHRN.