抄録
RIMs are multidomain adaptor proteins that were discovered as putative effectors for Rab3. RIM1α, 2α consist of an N-terminal Zn2+-finger domain, central PDZ and C2A domains, and a C-terminal C2B domain; RIM2β consist of an PDZ, C2A, and C2B domains; and RIM2γ, 3γ, and 4γ consist of only a C2B domain. While C2B domain is common to all RIMs, the function remains poorly understood. Moreover, the physiological roles played by RIM3, and RIM4 remain unclear.Here we show, C2B domains of all RIMs associate with voltage-dependent Ca2+ channel (VDCC) β-subunits to modulate currents of the P/Q-type VDCC. The most prominent effect of RIMs on VDCC currents was observed on inactivation parameters. Inactivation kinetics was markedly decelerated, resulting in the predominance of high voltage inactivation and an inactivation-resistant current component in the 2-s prepulse protocol. Since RIM3γ is reported as a post-synaptic protein, RIM3γ may modulate VDCCs at post-synapses. The similarly modulated inactivation properties by RIMs suggest that this function is a common feature of the RIM family. [J Physiol Sci. 2008;58 Suppl:S73]
