Chloride channels are a superfamily of poorly understood ion channels for chloride. These channels may conduct many different ions, but are named for chloride because its concentration in vivo is much higher than other anions. Several families of voltage-gated channels and ligand-gated channels (e.g., the CaCC families) have been characterized in humans.

Voltage-gated chloride channels display a variety of important physiological and cellular roles that include regulation of pH, volume homeostasis, organic solute transport, cell migration, cell proliferation and differentiation. Based on sequence homology the chloride channels can be subdivided into a number of groups.

General functions

Voltage-gated chloride channels are important for setting cell resting membrane potential and maintaining proper cell volume. These channels conduct Cl⁻ as well as other anions such as HCO₃⁻, I⁻, SCN⁻, and NO₃⁻. The structure of these channels are not like other known channels. The chloride channel subunits contain between 1 and 12 transmembrane segments. Some chloride channels are activated only by voltage (i.e., voltage-gated), while others are activated by Ca²⁺, other extracellular ligands, or pH.