Large conductance calcium-activated potassium channel subunit alpha-1 (KCa1.1) (KCa1.1)

The Large conductance calcium-activated potassium channel subunit alpha-1 (KCa1.1), encoded by the KCNMA1 gene, is a fundamental transmembrane protein that integrates intracellular calcium signaling with membrane voltage to regulate cellular excitability (UniProt Q12791). It is uniquely characterized by its high single-channel conductance and dual activation by both membrane depolarization and rising internal calcium concentrations (PubMed: 29100031). In smooth muscle, KCa1.1 activation promotes hyperpolarization and vasodilation, making it a key regulator of vascular tone and a target for treating hypertension and erectile dysfunction (PubMed: 24508611). Within the central nervous system, the channel modulates action potential duration, firing frequency, and neurotransmitter release, with mutations linked to epilepsy and movement disorders (PubMed: 21909131). Pharmacological agents targeting KCa1.1 include openers like BMS-204352, investigated for neuroprotection, and potent peptide blockers like iberiotoxin used in research (PubChem). Despite its therapeutic potential, the widespread expression of KCa1.1 across various tissues presents significant challenges for achieving tissue-specific modulation without systemic adverse effects (StatPearls).

Other names

BK channelMaxi-K channelSlo1KCNMA1Calcium-activated potassium channel subunit alpha-1K(VCA)alphaBKCA alpha

The channel acts as a voltage- and calcium-dependent potassium pore; its activation leads to potassium efflux, resulting in membrane hyperpolarization and subsequent inhibition of voltage-dependent processes such as calcium entry and neurotransmitter release (UniProt Q12791).