USH2A protein (usherin, Usher syndrome type-2A protein)

Function

• involved in hearing & vision
• interacts with collagen IV & fibronectin
  • interaction via laminin EGF-like domains
• integration into the basement membrane via collagen
• interacts with USH1C, WHRN via PDZ-binding motif
• 35 fibrinogen F3 modules
• 10 EGF domains
• 3 laminin-like domains
• component of interstereocilia ankle links in the inner ear sensory cells

Structure

• the PDZ-binding motif probably mediates the association with some of the PDZ domains of USH1C & WHRN (putative)
• contains 35 fibronectin F3 modules
• contains 10 laminin EGF-like domains
• contains 2 laminin G-like domains
• contains 1 laminin N-terminal domain

Compartment

• cell projection, stereocilium membrane
• single-pass type 1 membrane protein
• probable component of the interstereocilia ankle links in the inner ear sensory cells
• isoform 2: secreted

Alternative splicing

• named isoforms=3

Expression

• present in the basement membrane of many, but not all tissues
• expressed in retina, cochlea, small intestine, large intestine, pancreas, bladder, prostate, esophagus, trachea, thymus, salivary glands, placenta, ovary, fallopian tube, uterus, testis
• absent in heart, lung, liver, kidney, brain
• in the retina, present in Bruch's membrane

Pathology

• defects in USH2A result in Usher syndrome 2a
• defects in USH2A are a cause of autosomal recessive retinitis pigmentosa type-39

More general terms

• adhesion receptor

Additional terms

• retinitis pigmentosa (RP)
• Usher syndrome type IIA

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=7399
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:7399
• OMIM: https://mirror.omim.org/entry/268000
• OMIM: https://mirror.omim.org/entry/276901
• OMIM: https://mirror.omim.org/entry/608400
• UniProt: http://www.uniprot.org/uniprot/O75445.html