Abstract
We have recently cloned a channel homologous to DSC1 (drosophila sodium channel 1) in the honeybee. Despite sequence similarity with voltage-dependent Na+ channel, we demonstrate a strong calcium (Ca2+) permeation, and suggested that AmSC1 may belong to a new type of voltage-dependent calcium channel (VDCC), now named CaV4. Identification of a particular sequences for the selectivity filter (DEEA), for inactivation domain (MFL, homologous to the IFM of the NaV channel) and a C-terminus sequence containing a calmodulin (Cam)-binding site led us to analyze the singular permeation and the voltage and calcium-dependent inactivation properties of this new channel. Its voltage-dependence of activation and deactivation suggest an important role in the Ca influx during action potential