Cytoplasmic potassium channel subunit that modulates the characteristics of the channel-forming alpha-subunits (, ). Contributes to the regulation of nerve signaling, and prevents neuronal hyperexcitability (By similarity). Promotes expression of the pore-forming alpha subunits at the cell membrane, and thereby increases channel activity (By similarity). Promotes potassium channel closure via a mechanism that does not involve physical obstruction of the channel pore (, ). Promotes KCNA4 channel closure (, ). Modulates the functional properties of KCNA5 (By similarity). Enhances KCNB2 channel activity (By similarity). Binds NADPH and has NADPH-dependent aldoketoreductase activity (By similarity). Has broad substrate specificity and can catalyze the reduction of methylglyoxal, 9,10-phenanthrenequinone, prostaglandin J2, 4-nitrobenzaldehyde, 4-nitroacetophenone and 4-oxo-trans-2-nonenal (in vitro) (By similarity).
Subcellular locations: Cytoplasm, Membrane, Cell membrane, Cell projection, Axon, Synapse, Synaptosome, Cytoplasm, Cytoskeleton
Recruited to the cytoplasmic side of the cell membrane via its interaction with pore-forming potassium channel alpha subunits. Associates with microtubules when unphosphorylated.
Detected in myelinated nerve fibers in the spinal cord, in the juxtaparanodal region of the nodes of Ranvier, but also in the paranodal region . Detected in hippocampus (at protein level) . Detected in hippocampus .