CaV1.3 Ca2+ channels are voltage-gated L-type calcium channels, regulating many different physiological functions including neurotransmitter release in cochlear inner hair cells (IHCs) after sound-evoked stimulation. In IHCs, the CaV1.3 channel shows rapid activation after stimulation with very slow inactivation kinetics, whereas in other tissues (heart and brain) the channel underlies a very strong inactivation. The exact mechanism for the very slow inactivation observed in IHCs is not known so far. Interaction of the auxiliary β subunit with RIM2α, an active zone scaffolding protein, slows down calcium-dependent inactivation (CDI) and voltage-dependent inactivation (VDI); however, it does not fully account for the even slower inactivation kinetics observed in IHCs, as recently published by our lab. RIM binding proteins (RBPs), another group of active zone proteins, are known to interact with RIM and with the CaV1.3 α1 subunit C-terminus. We therefore hypothesized that interaction of the Ca2+ channel with both RIM and RBPs results in a large signaling complex that restrains gating transitions, leading to the slow inactivation kinetics of the CaV1.3 channel in IHCs.