K(Ca)2 and K(Ca)3.1 Channels in the Airways: A New Therapeutic Target

K+ channels are involved in many critical functions in lung physiology. Recently, the family of Ca2+-activated K+ channels (K-Ca) has received more attention, and a massive amount of effort has been devoted to developing selective medications targeting these channels. Within the family of K-Ca channels, three small-conductance Ca2+-activated K+ (K(Ca)2) channel subtypes, together with the intermediate-conductance K(Ca)3.1 channel, are voltage-independent K+ channels, and they mediate Ca2+-induced membrane hyperpolarization. Many K(Ca)2 channel members are involved in crucial roles in physiological and pathological systems throughout the body. In this article, different subtypes of K(Ca)2 and K(Ca)3.1 channels and their functions in respiratory diseases are discussed. Additionally, the pharmacology of the K(Ca)2 and K(Ca)3.1 channels and the link between these channels and respiratory ciliary regulations will be explained in more detail. In the future, specific modulators for small or intermediate Ca2+-activated K+ channels may offer a unique therapeutic opportunity to treat muco-obstructive lung diseases.