– Pore-forming, alpha-1C subunit of the voltage-gated calcium channel that gives rise to L-type calcium currents. Mediates influx of calcium ions into the cytoplasm, and thereby triggers calcium release from the sarcoplasm. Plays an important role in excitation-contraction coupling in the heart. Required for normal heart development and normal regulation of heart rhythm. Required for normal contraction of smooth muscle cells in blood vessels and in the intestine. Essential for normal blood pressure regulation via its role in the contraction of arterial smooth muscle cells. Long-lasting (L-type) calcium channels belong to the ‘high-voltage activated’ (HVA) group.