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Official Full Name
potassium inwardly-rectifying channel, subfamily J, member 2
Potassium channels are present in most mammalian cells, where they participate in a wide range of physiologic responses. The protein encoded by this gene is an integral membrane protein and inward-rectifier type potassium channel. The encoded protein, which has a greater tendency to allow potassium to flow into a cell rather than out of a cell, probably participates in establishing action potential waveform and excitability of neuronal and muscle tissues. Mutations in this gene have been associated with Andersen syndrome, which is characterized by periodic paralysis, cardiac arrhythmias, and dysmorphic features. [provided by RefSeq, Jul 2008]
KCNJ2; potassium inwardly-rectifying channel, subfamily J, member 2; IRK1; LQT7; SQT3; ATFB9; HHIRK1; KIR2.1; HHBIRK1; inward rectifier potassium channel 2; IRK-1; hIRK1; inward rectifier K+ channel KIR2.1; cardiac inward rectifier potassium channel; inward rectifier K(+) channel Kir2.1; inward rectifier potassium channel cIRK1; potassium channel, inwardly rectifying subfamily J member 2

Recent Research

KCNJ2, encodes Kir2.1, is a member of the classical inwardly rectifying potassium channel family (Kir2 subfamily). It is a 427 amino acid, double-channel transmembrane protein, located at both ends in the cytoplasm. It conducts a strong inward rectifier K+ current in a wide range of tissues and cell types, including neurons, skeletal muscle, cardiac myocytes, immune system, hippocampus, caudate, putamen and carcinoma cells. The KCNJ2 gene was first cloned by Kubo from a macrophage cell line. Similar to the other members of the Kir family, KCNJ2 is tetrameric, containing two transmembrane helix domains (M1 and M2), an ion-selective P-loop between M1 and M2, and cytoplasmic N-and C-terminal domains. Functionally, KCNJ2 plays a key role in maintaining the resting membrane potential and regulating cellular excitability in cardiac myocytes, skeletal muscle and neurons. Changes in the expression levels of K+ channels induced by aberrant KCNJ2 expression have substantial effects on cellular processes such as cell death, proliferation, apoptosis and adhesion, which are linked to a variety of cardiac and neurological disorders.

It is reported that KCNJ2 loss-of-function mutations result in four distinct arrhythmia syndromes, including Andersen-Tawil syndrome type 1 (ATS1, also denoted as long QT syndrome type 7 [LQT7]), short QT syndrome type 3(SQT), familial atrial fibrillation and CPVT3. ATS1 is a rare autosomal-dominant disorder. It is characterized by a phenotypic triad consisting of cardiac abnormalities (premature ventricular complexes, ventricular bigeminy, ventricular tachycardia and supraventricular, torsades de pointes, prominent electrocardiographic U waves and prolonged QT intervals) in addition to dysmorphic features and periodic paralysis.

In addition, gain-of-function KCNJ2 mutations cause atrial fibrillation (AF). Atrial fibrillation is the most common arrhythmia characterized by complex and irregular atrial electrical activity. One rare, genetic condition associated with increased risk of AF is the SQT, which is caused by mutations in genes involved in normal electrical function of the heart. SQT results in QT shortening and increased risk of sudden cardiac death.


  1. Anna B, et al. A Novel KCNJ2 Mutation Identified in an Autistic Proband Affects the Single Channel Properties of Kir2.1. Frontiers in Cellular Neuroscience, 2018, 12:76-.
  2. Whittaker D G, et al. Atrial arrhythmogenicity of KCNJ2 mutations in short QT syndrome: Insights from virtual human atria. PLOS Computational Biology, 2017, 13(6):e1005593-.
  3. Adams D S, et al. Bioelectric signalling via potassium channels: a mechanism for craniofacial dysmorphogenesis in KCNJ2-associated Andersen-Tawil Syndrome. The Journal of Physiology, 2016:n/a-n/a.
  4. Liu H, et al. Upregulation of the inwardly rectifying potassium channel Kir2.1 (KCNJ2) modulates multidrug resistance of small-cell lung cancer under the regulation of miR-7 and the Ras/MAPK pathway. Molecular Cancer, 2015, 14(1):59.

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