Potassium channels represent the most complex class of voltage-gated ion channels from both functional and structural standpoints. Their diverse functions include regulating 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 , shaker-related subfamily. This member contains six membrane-spanning domains with a shaker-type repeat in the fourth segment. It belongs to the delayed rectifier class , members of which allow nerve cells to efficiently repolarize following an action potential. It plays an essential role in T-cell proliferation and
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