Large-conductance calcium- and voltage-activated potassium channel (KCNMA1) (BK channel)

Large-conductance calcium- and voltage-activated potassium channels (BK channels), encoded by the KCNMA1 gene, are transmembrane ion channels widely distributed in excitable and non-excitable tissues, including neurons, muscle, and secretory cells[1][5][3]. They are distinguished by their high conductance for potassium and are activated synergistically by membrane depolarization and increases in intracellular calcium. BK channels play critical roles in regulating membrane potential, limiting cellular excitability, controlling neurotransmitter release, and enabling smooth muscle relaxation, among other physiological functions[1][5][7]. They are heterotetrameric in structure and can associate with modulatory β and γ subunits, and their diversity is increased by extensive alternative splicing[3][5]. Dysfunction or dysregulation of BK channels has been associated with a range of diseases, including epilepsy, hypertension, bladder and erectile dysfunction, and some types of cancer[1][3][4][5]. They are considered an important therapeutic target, though clinical success with BK channel modulators has to date been limited by safety concerns and efficacy challenges[1][6][4].

Other names

Big potassium channelBKCaMaxi-KSlo1KCa1.1Stretch-activated potassium channelKCNMA1 (gene/protein name)

Channel openers: Activate BK channels, increasing potassium efflux and causing hyperpolarization of cell membranes, reducing excitability and promoting smooth muscle relaxation[2][4][6]. Inhibitors/blockers (few in clinical use): Block potassium conductance, increasing cell excitability/contractility[4].