Human KCNIP1, a novel member of the neural calcium binding protein family, is a small calcium-binding protein with EF-hand-like domains. It varies from others in its N-terminus and is an integral subunit of native Kv4 channel complexes, potentially regulating A-type currents and neuronal excitability in response to intracellular calcium changes. Predominantly expressed at GABAergic synapses, KCNIP1 is a neuronal calcium sensor protein linked to K(+) channel modulation, GABAergic transmission, and cell death.