Probably participates in establishing action potential waveform and excitability of neuronal and muscle tissues. Inward rectifier potassium channels are characterized by a greater tendency to allow potassium to flow into the cell rather than out of it. Their voltage dependence is regulated by the concentration of extracellular potassium; as external potassium is raised, the voltage range of the channel opening shifts to more positive voltages. The inward rectification is mainly due to the blockage of outward current by internal magnesium. Can be blocked by extracellular barium or cesium. Defects in KCNJ2 are the cause of long QT syndrome type 7 (LQT7); also called Andersen syndrome or Andersen cardiodysrhythmic periodic paralysis. Long QT syndromes are heart disorders characterized by a prolonged QT interval on the ECG and polymorphic ventricular arrhythmias. They cause syncope and sudden death in response to excercise or emotional stress. LQT7 manifests itself as a clinical triad consisting of potassium-sensitive periodic paralysis, ventricular ectopy and dysmorphic features. Defects in KCNJ2 are the cause of short QT syndrome type 3 (SQT3). Short QT syndromes are heart disorders characterized by idiopathic persistently and uniformly short QT interval on ECG in the absence of structural heart disease in affected individuals. They cause syncope and sudden death. SQT3 has a unique ECG phenotype characterized by asymmetrical T waves. Defects in KCNJ2 are the cause of familial atrial fibrillation type 9 (ATFB9). ATFB9 is a familial form of atrial fibrillation, a common sustained cardiac rhythm disturbance. Atrial fibrillation is characterized by disorganized atrial electrical activity and ineffective atrial contraction promoting blood stasis in the atria and reduces ventricular filling. It can result in palpitations, syncope, thromboembolic stroke, and congestive heart failure. Belongs to the inward rectifier-type potassium channel (TC 1.A.2.1) family. KCNJ2 subfamily. Note: This description may include information from UniProtKB.
Protein type: Channel, potassium; Membrane protein, integral; Membrane protein, multi-pass
Biological Process: cellular potassium ion homeostasis; potassium ion import; potassium ion transport; protein homotetramerization; regulation of resting membrane potential; regulation of skeletal muscle contraction via membrane action potential