BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in potassium voltage-gated channel subfamily A member 1 (KCNA1)
KCNA1 is also called voltage-gated K(+) channel HuKI, voltage-gated potassium channel HBK1, or voltage-gated potassium channel subunit Kv1.1. It mediates transmembrane potassium transport in excitable membranes, primarily in the brain and the central nervous system, but also in the kidney. It is involved in the regulation of the membrane potential and nerve signaling, and prevents neuronal hyperexcitability. Assuming opened or closed conformations in response to the voltage difference across the membrane, the protein forms a tetrameric potassium-selective channel through which potassium ions may pass in accordance with their electrochemical gradient. Voltage-gated potassium (Kv) channels are composed of alpha subunits, which form the actual conductance pore, and cytoplasmic beta subunits, which are auxiliary proteins that associate with alpha subunits to modulate the activity of the Kv channel. KCNA1 is an alpha subunit that forms functional homo- or hetero-tetrameric channels (with other Kv1/KCNA alpha subunits) through its BTB/POZ domain, also known as tetramerization (T1) domain, which is a versatile protein-protein interaction motif.
Structure:1EXB: Rattus norvegicus potassium channel Kv1.1 in complex with KV Beta2 Protein, contacts at 4A.
Comment:Beta subunts are auxiliary proteins that associate with the alpha subunit (Kv1.1), sometimes in an alpha4beta4 stoichiometry, and modulate the activity of the Kv channel.
Jiyao W et al.(2023). "The conserved domain database in 2023.",