Potassium calcium-activated channel subfamily M alpha 1 (BK channel)

The Potassium calcium-activated channel subfamily M alpha 1, commonly known as the BK channel or KCa1.1, is a unique ion channel dually regulated by membrane depolarization and increases in intracellular calcium concentration [8, 13, 14]. It is characterized by an exceptionally large single-channel conductance, which allows for rapid potassium efflux and subsequent membrane hyperpolarization [14, 18]. This channel plays a critical role in regulating cellular excitability across various tissues, including the nervous system, where it modulates action potential duration and neurotransmitter release, and smooth muscle, where it controls vascular and airway tone [4, 5, 9]. Dysregulation of BK channel activity is linked to a wide range of pathologies, such as hypertension, epilepsy, asthma, and erectile dysfunction [1, 2, 3, 9]. Pharmacological modulation of the BK channel involves both activators (openers) to treat conditions like hypertension and epilepsy, and inhibitors (blockers) used primarily in research or for specific therapeutic contexts [6, 11, 12]. Additionally, altered expression of the channel has been implicated in the progression and malignancy of several cancers, including breast and prostate cancer [3, 4]. However, the ubiquitous expression of the channel presents significant challenges for drug development due to the potential for systemic off-target effects [4, 8].

Other names

BKCaMaxi-KKCa1.1Slo1KCNMA1Big potassium channelhSloMSLO1SAKCACADEDSPNKD3Large-conductance calcium-activated potassium channel

Modulation of potassium efflux through the channel pore to regulate membrane potential; activators promote hyperpolarization, while inhibitors promote depolarization.