Large-conductance calcium-activated potassium channel subunit alpha-1 (BK channel) (BK channel)

The large-conductance calcium-activated potassium channel, often referred to as the BK channel or KCa1.1, is a fundamental regulator of cellular excitability across diverse tissues. It is uniquely characterized by its dual sensitivity to both membrane voltage and intracellular calcium levels, allowing it to integrate electrical and chemical signals (UniProt: Q12791). In smooth muscle cells, BK channel activation promotes hyperpolarization and subsequent vasodilation, making it a significant target for cardiovascular and urological conditions (PubMed: 25100715). Within the nervous system, these channels modulate action potential duration and neurotransmitter release, with dysfunctions linked to epilepsy and paroxysmal movement disorders (PubMed: 30635414). Pharmacological strategies include the use of activators to treat hypertension or asthma and inhibitors to study neuronal signaling or manage specific cancers, though achieving tissue specificity remains a major challenge (StatPearls: NBK541043).

Other names

BKCaMaxi-KKCa1.1Slo1KCNMA1Calcium-activated potassium channel subunit alpha-1SlohSlo

BK channel modulators function by altering the open-state probability of the channel pore. Activators (openers) shift the voltage-activation curve toward more negative potentials or increase calcium sensitivity, facilitating potassium efflux and membrane hyperpolarization (PubMed: 25100715). Inhibitors (blockers) physically occlude the pore or stabilize the closed conformation, preventing potassium efflux and maintaining or increasing cellular excitability (PubMed: 15131015).