Voltage-sensitive calcium channels (VSCC) mediate the entry of calcium ions into excitable cells and are also involved in a variety of calcium-dependent processes, including muscle contraction, hormone or neurotransmitter release, gene expression, cell motility, cell division and cell death. Encodes a dihydropyridine- and diltiazem-sensitive current in larval body wall muscle. Vital for embryonic development. Expressed in the adult body, head and leg. Highly expressed in the embryonic nervous system. Faintly expressed in embryos at 9-12 hours. Expression increases rapidly as the nervous system matures, peaking just prior to hatching. A second peak is observed in late pupal stages around 73-108 hours postpuparium. Each of the four internal repeats contains five hydrophobic transmembrane segments (S1, S2, S3, S5, S6) and one positively charged transmembrane segment (S4). S4 segments probably represent the voltage-sensor and are characterized by a series of positively charged amino acids at every third position. Belongs to the calcium channel alpha-1 subunit (TC 1.A.1.11) family. It is uncertain whether Met-1, Met-494, Met-539, Met-544 or Met-553 is the initiator.