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 (By similarity). MDL-alpha1 encodes a dihydropyridine- and diltiazem-sensitive current in larval body wall muscle. Predominantly expressed in the larval body wall musculature. In adults, highest expression in thorax followed by head and at a lower extent by abdomen. Late embryonic. 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.