K_Ca3.1 is part of the Ca²⁺ activated K⁺ channel family, whose members share the characteristic of being activated by intracellular Ca²⁺. The channel has an intermediate conductance, is voltage insensitive and is activated by Ca²⁺ in the submicromolar range. The channel has a similar topology to that of K_V channels, that is, six transmembrane domains and intracellular N- and C-termini.

The functional role of the channel is to set the cell membrane potential at negative values so as to aid in the electrochemical transport of other ions such as Cl^- and Ca²⁺. Indeed, K_Ca3.1 has a key role in sustaining the Ca²⁺ influx in activated T lymphocytes and in regulating Cl^- secretion from colon epithelium. Therefore, specific blockers of the K_Ca3.1 channel have been proposed for the treatment of several diseases including autoimmune diseases, secretory diarrhea and sickle cell anemia.