The present invention relates to KCNQ proteins defining potassium channels. In particular, the invention concerns the human KCNQ2, human KCNQ3, murine KCNQ2, and rat KCNQ2 proteins reported herein. KCNQ2 and KCNQ3 proteins are nervous system-selective and may be involved in neurotransmission and neuroprotection. The KCNQ2 and KCNQ3 of the present invention can be used to assay for modulators of the proteins, which would be useful in treatment of such disorders as ataxia, myokymia, seizures, Alzheimer's disease, Parkinson's disease, age-associated memory loss, learning deficiencies, motor neuron diseases, epilepsy, stroke, and the like.