Voltage-Gated Ca 2+ Channels

Calcium (Ca 2+ ) channels are present in excitable cell membranes in brain, heart, skeletal and smooth muscles, etc. They open and close upon changes in membrane potential. Their molecular structures determine their opening and closing kinetics. Influx of Ca 2+ into the cells through open channels leads to their binding to intracellular structural molecules such as calmodulin. This, in turn, is essential for channel kinetics and cellular functions. Structural diversities of Ca 2+ channels relate to different functions in various tissues, such as neurotransmitter release or cardiac and smooth muscle contraction. Mutations of genes encoding Ca 2+ channels can lead to various diseases (channelopathies).