Regulation of BK Channel Activity by Cholesterol and Its Derivatives

Cholesterol (CLR) is an essential structural lipid in the plasma membrane of animal cells. In addition, CLR has been widely recognized as a critical modulator of protein function, including ion channels. Voltage- and Ca²⁺-gated K⁺ (BK) channels control a wide variety of physiological processes, including cell excitability, smooth muscle contractility, sensory perception, neurotransmitter release, and hormone secretion. Thus, disruption of BK currents has been implicated in the pathophysiology of prevalent human diseases. The current chapter reviews the literature documenting CLR modulation of BK channel function at a variety of levels ranging from organ systems to artificial lipid bilayers. We discuss the use of CLR isomers and structural analogs as a tool to help in discerning the mechanisms underlying CLR-driven modification of BK current. The chapter is finalized with an overview of the phenomenology and potential mechanisms that govern CLR control over the alcohol (ethyl alcohol, ethanol) sensitivity of BK channels. Studies on CLR regulation of BK currents may ultimately pave the way for novel therapeutic approaches to combat prevalent pathophysiological and morbid conditions.