KCNB1

Potassium voltage-gated channel, Shab-related subfamily, member 1, also known as KCNB1 or Kv2.1, is a is_associated_with::protein that, in humans, is encoded by the KCNB1 is_associated_with::gene.

Species and tissue distribution
Kv2.1 channels are widely expressed in various tissues in mammals, including humans. They are found in is_associated_with::cardiomyocytes, skeletal muscles, vascular smooth muscles, placental vasculature, retina, and pancreatic β-cells.

Function
Voltage-gated potassium (Kv) channels represent the most complex class of voltage-gated ion channels from both functional and structural standpoints. Their diverse functions include regulating is_associated_with::neurotransmitter release, heart rate, insulin secretion, neuronal excitability, epithelial electrolyte transport, smooth muscle contraction, and cell volume. Four sequence-related potassium channel genes - shaker, shaw, shab, and shal - have been identified in Drosophila, and each has been shown to have human homolog(s). This gene encodes a member of the potassium channel, voltage-gated, shab-related subfamily. This member is a delayed rectifier potassium channel and its activity is modulated by some other family members.

In mouse cardiomyocytes, Kv2.1 channel is the molecular substrate of major repolarization current IK-slow2. Transgenic mice, expressing a dominant-negative isoform of Kv2.1, exhibit markedly prolonged is_associated_with::action potentials and demonstrate arrhythmia. In mammalian CNS neurons, Kv2.1 is a predominant delayed rectifier K+ current that regulates neuronal excitability, action potential duration, and tonic spiking. In is_associated_with::Drosophila is_associated_with::photoreceptor cells, the Kv2 channel is the key component of light-induced membrane voltage response. Genetic abolition of this current dramatically decreases photoreceptor information capacity.

Interactions
KCNB1 has been shown to interact with:
 * is_associated_with::KCNH1, and
 * is_associated_with::PTPRE.