EF-hand protein Ca2+ buffers regulate Ca2+ influx and exocytosis in sensory hair cells.

ABSTRACT: EF-hand Ca(2+)-binding proteins are thought to shape the spatiotemporal properties of cellular Ca(2+) signaling and are prominently expressed in sensory hair cells in the ear. Here, we combined genetic disruption of parvalbumin-α, calbindin-D28k, and calretinin in mice with patch-clamp recording, in vivo physiology, and mathematical modeling to study their role in Ca(2+) signaling, exocytosis, and sound encoding at the synapses of inner hair cells (IHCs). IHCs lacking all three proteins showed excessive exocytosis during prolonged depolarizations, despite enhanced Ca(2+)-dependent inactivation of their Ca(2+) current. Exocytosis of readily releasable vesicles remained unchanged, in accordance with the estimated tight spatial coupling of Ca(2+) channels and release sites (effective "couplin

SUBMITTER: Pangrsic T 

PROVIDER: S-EPMC4352837 | biostudies-literature | 2015 Mar

REPOSITORIES: biostudies-literature