Small conductance calcium-activated potassium channel protein 2 (KCa2.2) (KCa2.2)

Small conductance calcium-activated potassium channel protein 2 (KCa2.2), encoded by the KCNN2 gene, is a voltage-independent potassium channel activated by increases in intracellular calcium levels [UniProt, 2024]. It plays a critical role in regulating the excitability of neurons by contributing to the medium afterhyperpolarization (mAHP) following an action potential, thereby limiting the firing frequency of cells [PubMed: 10804210]. In the central nervous system, KCa2.2 is involved in synaptic plasticity, learning, and memory processes [PubMed: 16959744]. Beyond the brain, it is significantly expressed in the heart, particularly in the atria, where it contributes to cardiac repolarization [PubMed: 21148300]. Dysregulation of KCa2.2 is linked to various neurological disorders such as ataxia and epilepsy, as well as cardiovascular conditions like atrial fibrillation [NCBI Gene, 2024]. Pharmacological modulation of KCa2.2, using either activators like CyPPA to reduce excitability or blockers like apamin to enhance it, represents a promising therapeutic strategy for these conditions [Guide to Pharmacology, 2024].

Other names

SK2SKCA2KCNN2Small conductance calcium-activated potassium channel 2hSK2

Drugs targeting KCa2.2 typically act as either pore blockers, which prevent potassium efflux, or allosteric modulators that alter the channel's sensitivity to intracellular calcium ions [Guide to Pharmacology, 2024].