Protein Details: Potassium voltage-gated channel subfamily A member 2

Function

Voltage-gated potassium channel that mediates transmembrane potassium transport in excitable membranes; primarily in the brain and the central nervous system; but also in the cardiovascular system. Prevents aberrant action potential firing and regulates neuronal output. Forms tetrameric potassium-selective channels through which potassium ions pass in accordance with their electrochemical gradient. The channel alternates between opened and closed conformations in response to the voltage difference across the membrane . Can form functional homotetrameric channels and heterotetrameric channels that contain variable proportions of KCNA1; KCNA2; KCNA4; KCNA5; KCNA6; KCNA7; and possibly other family members as well; channel properties depend on the type of alpha subunits that are part of the channel . Channel properties are modulated by cytoplasmic beta subunits that regulate the subcellular location of the alpha subunits and promote rapid inactivation of delayed rectifier potassium channels . In vivo; membranes probably contain a mixture of heteromeric potassium channel complexes; making it difficult to assign currents observed in intact tissues to a particular potassium channel family member. Homotetrameric KCNA2 forms a delayed-rectifier potassium channel that opens in response to membrane depolarization; followed by slow spontaneous channel closure . In contrast; a heteromultimer formed by KCNA2 and KCNA4 shows rapid inactivation. Response to toxins that are selective for KCNA1; respectively for KCNA2; suggests that heteromeric potassium channels composed of both KCNA1 and KCNA2 play a role in pacemaking and regulate the output of deep cerebellar nuclear neurons. KCNA2-containing channels play a presynaptic role and prevent hyperexcitability and aberrant action potential firing. Response to toxins that are selective for KCNA2-containing potassium channels suggests that in Purkinje cells; dendritic subthreshold KCNA2-containing potassium channels prevent random spontaneous calcium spikes; suppressing dendritic hyperexcitability without hindering the generation of somatic action potentials; and thereby play an important role in motor coordination. Plays a role in the induction of long-term potentiation of neuron excitability in the CA3 layer of the hippocampus (By similarity). May function as down-stream effector for G protein-coupled receptors and inhibit GABAergic inputs to basolateral amygdala neurons. May contribute to the regulation of neurotransmitter release; such as gamma-aminobutyric acid (GABA). Contributes to the regulation of the axonal release of the neurotransmitter dopamine. Reduced KCNA2 expression plays a role in the perception of neuropathic pain after peripheral nerve injury; but not acute pain. Plays a role in the regulation of the time spent in non-rapid eye movement (NREM) sleep (By similarity)

Sequence

PDB Structures

Ligand Binding