The KCa1.1 channel (also known as BKCa, Maxi K+ or slo) is part of a structurally diverse group of K+ channels that are activated by an increase in intracellular Ca2+. KCa1.1 shows a large single channel conductance when recorded electrophysiologically and hence its name. It differs from the rest of the subfamily members in that it can be activated by both an increase in intracellular Ca2+ and by membrane depolarization. In addition, the KCa1.1 channel structurally differs from the other Ca2+-dependent K+ channels.