Mouse wild-type and Anxa5-null utricles and hair bundles

ABSTRACT: The phospholipid- and Ca2+-binding protein annexin A5 (ANXA5) is the most abundant membrane-associated protein of ~P23 mouse vestibular hair bundles, present at ~15,000 copies per stereocilium, which is ~2% of the total protein there. Although seven other annexin genes are expressed in mouse utricles, mass spectrometry showed that none were upregulated in stereocilia of Anxa5-/- mice. Annexins have been proposed to mediate Ca2+-dependent repair of membrane lesions, which could be part of the repair mechanism in hair cells after noise damage. Nevertheless, Anxa5-/- mice not only have normal hearing or balance, but are identical to wild-type mice in their temporary or permanent hearing changes following noise exposure. We suggest that the significant amounts of ANXA2 and ANXA6 that are present in the hair-cell cytoplasm can substitute in any function carried out by ANXA5, and that ANXA5 may be playing a hitchhiker role in the bundle. These results demonstrate that abundance of a protein in a specific compartment or cellular structure does not necessarily imply functional significance.

INSTRUMENT(S): LTQ Velos

ORGANISM(S): Mus Musculus (mouse)

TISSUE(S): Utricle, Inner Ear, Vestibular Hair Cell

SUBMITTER: Peter Barr-Gillespie  

LAB HEAD: Peter Barr-Gillespie

PROVIDER: PXD003005 | Pride | 2016-06-09

REPOSITORIES: Pride