Big potassium channel (BK channel)

The big potassium channel, also known as the BK channel, is a large-conductance, calcium- and voltage-activated potassium channel encoded by the KCNMA1 gene (alias Slo1). It is widely expressed in both excitable and non-excitable tissues, including neurons, muscle, vascular smooth muscle, kidney, and secretory epithelia[1][3][5]. The channel has a unique ability to integrate changes in membrane potential and intracellular calcium concentration to control the efflux of potassium ions, thereby regulating cellular excitability, neurotransmitter release, muscle contraction, and vascular tone[1][3][5]. Structurally, the channel is a tetramer of α-subunits, each containing a voltage-sensing domain, a pore-gated domain, and a cytosolic calcium-sensing domain; auxiliary β and γ subunits further modulate its functional properties[1][3][5]. Aberrant BK channel function is implicated in several diseases, notably epilepsy, hypertension, stroke, and bladder dysfunction, and it is considered a promising but challenging target for drug development due to its tissue distribution and regulatory complexity[1][2][5].

Other names

BKCaMaxi-Kslo1KCa1.1Large-conductance calcium-activated potassium channel

Channel blocker (inhibitor), Channel activator (agonist), Modulation of channel gating by voltage or calcium, Alters potassium ion efflux, Hyperpolarizes cell membrane, Attenuates hyperexcitability, Promotes smooth muscle relaxation