Also referred to as:
Small-conductance Ca2+- activated K+ (SK) channel
Small conductance calcium-activated potassium channel protein 3
SK3 channel
SKCa 3
KCa channel
About:
The SK3 channel is important for afterhyperpolarization following an action potential. One channel is made from four monomers which all contain six transmembrane segments, connected via a single pore loop. The N-termini and the C-termini are both located at the intracellular side of the membrane. A calmodulin molecule is located at the C-termini of the SK3 channel via a CaM-binding domain. Calmodulin will activate the SK3 channel upon binding of Ca2+. SK3 channels are not voltage-dependent. (Gu et al. 2018; Köhler et al. 1996; Weisbrod, 2020)
Calcium-induced activation of the SK3 channel will cause hyperpolarization of endothelial cells, resulting in hyperpolarization of the adjacent muscle cell, which is also known as an endothelium-derived hyperpolarizing factor (EDHF). This hyperpolarization of the muscle cells will then result in dilation in resistance arteries (Ledoux et al. 2006; Kohler et al. 2010).
The level of SK3 channel expression in endothelial cells was found to be important for vascular tone and blood pressure in mice. (Taylor et al. 2003)