Voltage-gated potassium channel that plays an important role in the rapid repolarization of fast-firing brain neurons. The channel opens in response to the voltage difference across the membrane, forming a potassium-selective channel through which potassium ions pass in accordance with their electrochemical gradient (PubMed:10482766, PubMed:14679187). Can form functional homotetrameric channels and heterotetrameric channels that contain variable proportions of KCNC2, and possibly other family members as well (PubMed:10482766, PubMed:14679187). Contributes to fire sustained trains of very brief action potentials at high frequency in pallidal neurons (PubMed:10482766). Heteromultimer with KCNG3, KCNG4 and KCNV2 (By similarity). Heteromultimer with KCNC2 (PubMed:10482766, PubMed:14679187). Heterotetramer with KCNC3 (By similarity). Interacts with the ancillary subunits KCNE1 and KCNE2; the interaction modulates channel activity (PubMed:14679187). Localizes in parallel fiber membranes, distributed on the perisynaptic and extrasynaptic membranes away from the active zones. Expressed in brain (PubMed:1378392). Expressed in globus pallidal neurons of the basal ganglia (at protein level) (PubMed:10482766). Detected on Purkinje cells in the cerebellum molecular layer (at protein level) (PubMed:20857303). The segment S4 is probably the voltage-sensor and is characterized by a series of positively charged amino acids at every third position. The tail may be important in modulation of channel activity and/or targeting of the channel to specific subcellular compartments. N-glycosylated; contains sialylated glycans. Belongs to the potassium channel family. C (Shaw) (TC 1.A.1.2) subfamily. Kv3.1/KCNC1 sub-subfamily.