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Mol Cell Neurosci. 2010 Jul;44(3):246-59. doi: 10.1016/j.mcn.2010.03.011. Epub 2010 Apr 2.

Modulation of Cav1.3 Ca2+ channel gating by Rab3 interacting molecule.

Author information

1
Institute of Pharmacy, Pharmacology and Toxicology, University of Innsbruck, Peter-Mayr-Strasse 1/I, A-6020 Innsbruck, Austria; Center of Molecular Biosciences Innsbruck (CMBI), Innsbruck, Austria.

Abstract

Neurotransmitter release and spontaneous action potentials during cochlear inner hair cell (IHC) development depend on the activity of Ca(v)1.3 voltage-gated L-type Ca(2+) channels. Their voltage- and Ca(2+)-dependent inactivation kinetics are slower than in other tissues but the underlying molecular mechanisms are not yet understood. We found that Rab3-interacting molecule-2alpha (RIM2alpha) mRNA is expressed in immature cochlear IHCs and the protein co-localizes with Ca(v)1.3 in the same presynaptic compartment of IHCs. Expression of RIM proteins in tsA-201 cells revealed binding to the beta-subunit of the channel complex and RIM-induced slowing of both Ca(2+)- and voltage-dependent inactivation of Ca(v)1.3 channels. By inhibiting inactivation, RIM induced a non-inactivating current component typical for IHC Ca(v)1.3 currents which should allow these channels to carry a substantial window current during prolonged depolarizations. These data suggest that RIM2 contributes to the stabilization of Ca(v)1.3 gating kinetics in immature IHCs.

PMID:
20363327
DOI:
10.1016/j.mcn.2010.03.011
[Indexed for MEDLINE]

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