Small conductance calcium-activated potassium channel protein 2 (SK2)

KCNN2 encodes the small conductance calcium-activated potassium channel protein 2, also known as SK2 or KCa2.2. This is an integral membrane protein that forms a voltage-independent, calcium-activated potassium channel. The channel is composed of four subunits and includes calmodulin-binding domains; calmodulin remains constitutively attached to the C terminus and confers Ca²⁺ sensitivity to the channel. KCNN2 channels mediate voltage-independent transmembrane transfer of potassium ions activated solely by intracellular Ca²⁺ levels, not by changes in membrane potential. They play a critical role in regulating neuronal excitability by contributing to the slow component of synaptic afterhyperpolarization (AHP) following action potentials in neurons, modulating firing patterns and responsiveness to synaptic input patterns in both central nervous system neurons and cardiomyocytes, and in cardiac tissue integrating beat-to-beat changes in intracellular Ca²⁺ with membrane potential dynamics. Upregulation has been linked with atrial fibrillation pathophysiology.

Other names

KCNN2KCa2.2

Channel blocker