KV2.1 is a member of the voltage-gated K+ channel superfamily. Together with the closely related KV2.2 protein they form the KV2 subfamily also known as Shab.1
As with all KV channels, KV2.1 possesses the signature structure of the voltage-dependent K+ channels: six membrane-spanning domains with intracellular N and C termini. The functional KV channel is a tetramer that can either be a homotetramer or a heteromer of KV2.1 and KV2.2 subunits.
Both KV2.1 and KV2.2 channels are known as delayed rectifiers that is, channels that are activated by changes in membrane potential (depolarization) but inactivate very slowly. The current they form is known as IK or IDR. Accessory subunits such as KChaP and the electrically silent a subunits KV8 and KV9 can modulate biochemical and biophysical properties of KV2.1.2
KV2.1 is widely expressed throughout the body including brain, lung, pancreas, skeletal muscle and pulmonary artery.2
The main function of KV2.1 is to maintain membrane potential and to modulate the electrical excitability in neurons and muscle. In rat pulmonary artery it probably mediates hypoxic pulmonary vasoconstriction together with the KV9.3 subunit.3
Several toxins from spider venoms are potent blockers (affecting the channels in the nanomolar range) of KV2.1channels. Among these the most potent and selective are Stromatoxin-1 (#STS-350), (12.7 nM)4 and Hanatoxin (42 nM).4
