Integrin Alpha 8 (ITGa8)

Mechanosensory hair cells within the neuroepithelia of the cochlea and vestibule have stereocilia that are indispensable for mechanosensation. Evans and Muller (2000) demonstrated that integrin alpha-8/beta-1, its ligand fibronectin, and the integrin-regulated focal adhesion kinase colocalize to the apical hair cell surface where stereocilia are forming.

In mice homozygous for a targeted mutation of integrin alpha-8, the colocalization is perturbed, and hair cells in the utricle, a vestibular subcompartment, lack stereocilia or contain malformed stereocilia. Most integrin alpha-8/beta-1-deficient mice die soon after birth due to kidney defects. Many of the surviving mice have difficulty balancing, consistent with the structural defects of the inner ear.