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:25401298). Can form functional homotetrameric channels and heterotetrameric channels that contain variable proportions of KCNC2, and possibly other family members as well. Contributes to fire sustained trains of very brief action potentials at high frequency in pallidal neurons. Heteromultimer with KCNG3, KCNG4 and KCNV2 (By similarity). Heteromultimer with KCNC2 (By similarity). Heterotetramer with KCNC3 (PubMed:23734863). Interacts with the ancillary subunits KCNE1 and KCNE2; the interaction modulates channel activity (By similarity). Localizes in parallel fiber membranes, distributed on the perisynaptic and extrasynaptic membranes away from the active zones. 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. The disease is caused by variants affecting the gene represented in this entry. Belongs to the potassium channel family. C (Shaw) (TC 1.A.1.2) subfamily. Kv3.1/KCNC1 sub-subfamily.