KCNN1

KCNN1, also known as SK1 or KCa2.1, is a human gene that encodes a small-conductance calcium-activated potassium channel subunit. It is a member of the KCNN family and contributes to neuronal excitability and the afterhyperpolarization that follows action potentials.

The channel product formed by KCNN1 can assemble as homo- or heterotetramers and is directly gated by intracellular calcium through calmodulin, independent of membrane potential. Activation results in potassium efflux that hyperpolarizes the cell membrane, thereby shaping neuronal firing patterns and synaptic integration.

KCNN1 transcripts are widely expressed in the central nervous system, including the hippocampus, cortex, and cerebellum, with reports of expression in some peripheral tissues. In neurons, the SK1 channel localizes to somatic and dendritic membranes and participates in regulating the duration and frequency of action potential bursts as well as synaptic plasticity.

Pharmacologically, KCNN1 channels are blocked by the peptide apamin. They can be positively modulated by compounds such as 1-EBIO, NS309, and CyPPA, which enhance calcium-dependent activation. This pharmacology makes SK channels a focus of studies on neuronal excitability and potential therapeutic targets.

In research contexts, KCNN1 function is investigated in relation to epilepsy, motor coordination, learning, and cognitive processes, with ongoing interest in exploiting SK channels for neuroprotective or cognitive-enhancing strategies.