Cardiac potassium channel protein

Cardiac potassium channel proteins form a large family of transmembrane ion channels highly expressed in cardiac tissue. They are integral membrane proteins assembled as tetramers around a central pore, with each subunit containing six transmembrane helices (notably S4 as the voltage sensor, S5/S6 and pore loop as the ion-conducting region). These channels mediate the outward flow of potassium ions, driving repolarization and termination of the cardiac action potential, which is critical for normal cardiac rhythm. There are multiple subtypes, including voltage-gated potassium channels (e.g., KCNQ1 for IKs, KCNH2/hERG for IKr, and Kir6.2 for IKATP), each contributing to different phases of the cardiac action potential and subject to distinct regulation and pharmacology. Mutations or drug-induced dysfunction in these channels are major causes of cardiac arrhythmias and represent a significant concern for drug safety testing and cardiovascular therapeutics

Other names

Cardiac K+ channelCardiac potassium channelCardiac KV channelCardiac voltage-gated potassium channelCardiac delayed rectifier potassium channelCardiac KCNQ1 (for one major subtype)Cardiac hERG channel (for another major subtype)Cardiac IKs channelCardiac IKr channel

Blockade of K+ channel (prolongs repolarization, antiarrhythmic effect) Modulation of channel opening/closing (gating modulation) Prolongation of cardiac action potential duration Modulation by protein kinase A (PKA) phosphorylation