CaBP1 and 2 Enable Sustained CaV1.3 Calcium Currents and Synaptic Transmission in Inner Hair Cells
January 2024
CaBP1 CaBP2 calcium currents cochlear inner hair cells double knockout mouse model voltage-dependent inactivation calcium-dependent inactivation neurotransmitter release synaptic release auditory nerve viral gene transfer exocytosis calcium-binding proteins inner hair cells KO mouse model hearing function
TLDR CaBP1 and CaBP2 are important for maintaining hearing by supporting continuous calcium currents and nerve signaling in the ear.
The study investigates the role of calcium-binding proteins CaBP 1 and 2 in the inactivation of calcium currents in cochlear inner hair cells. The authors used a double knockout (KO) mouse model lacking both CaBP1 and CaBP2 and found that both proteins contribute to voltage-dependent and calcium-dependent inactivation, with CaBP2 being more effective. This inactivation is crucial for the sustained neurotransmitter release and sound encoding in cochlear hair cells. The study also found that synaptic release was reduced in the double KO, leading to depressed activity within the auditory nerve. The reintroduction of CaBP2 through viral gene transfer largely restored hearing function, normal calcium current properties, and exocytosis. However, the study did not clarify how CaBP1 and CaBP2 act together or the effect of the sole re-expression of CaBP1 in the double KO.
