Recombinant Mouse Usherin (Ush2A), partial

Function

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)

Subcellular Location

Secreted

Tissue Specificity

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)

Subunit

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)

• Huang D. et al. Identification of the mouse and rat orthologs of the gene mutated in Usher syndrome type IIA and the cellular source of USH2A mRNA in retina, a target tissue of the disease. — Genomics (2002)
• Liu X. et al. Biochemical and genetic analyses of murine usherin (Ush2A). (MAY-)
• Church D.M. et al. Lineage-specific biology revealed by a finished genome assembly of the mouse. — PLoS Biol. (2009)
• Bhattacharya G. et al. Localization and expression of usherin: a novel basement membrane protein defective in people with Usher's syndrome type IIa. — Hear. Res. (2002)
• Adato A. et al. Usherin, the defective protein in Usher syndrome type IIA, is likely to be a component of interstereocilia ankle links in the inner ear sensory cells. — Hum. Mol. Genet. (2005)
• Reiners J. et al. Scaffold protein harmonin (USH1C) provides molecular links between Usher syndrome type 1 and type 2. — Hum. Mol. Genet. (2005)
• Michalski N. et al. Molecular characterization of the ankle-link complex in cochlear hair cells and its role in the hair bundle functioning. — J. Neurosci. (2007)
• Yang J. et al. Ablation of whirlin long isoform disrupts the USH2 protein complex and causes vision and hearing loss. — PLoS Genet. (2010)