Dual Function of the Voltage-Dependent Ca2+ Channel α2δ Subunit in Current Stimulation and Subunit Interaction

mational changes induced by a2d subunit coassembly. and Kevin P. Campbell The importance of the a2d subunit for Ca1 channel funcHoward Hughes Medical Institute tion is highlighted by the Caenorhabditis elegans uncDepartment of Physiology and Biophysics 36 a2d subunit mutant, which yields the same phenotype University of Iowa College of Medicine as the unc-2 a1 subunit loss of function mutant (Schafer Iowa City, Iowa 52242 and Kenyon, 1995). To understand how the a2d subunit interacts with the other channel subunits, it is important to establish its Summary transmembrane topology, since the b subunit is entirely cytoplasmic and the a1 subunit contains extensive intraVoltage-dependent Ca21 channels are modulated by cellular domains. Hydropathy analysis of the cloned a2d complex interactions with the a2d subunit. In vitro subunit shows the presence of three hydrophobic regions suggesting 3 potential transmembrane domains, translation was used to demonstrate a single trans-