KCNJ2
Identifiers
Aliases	KCNJ2, ATFB9, HHBIRK1, HHIRK1, IRK1, KIR2.1, LQT7, SQT3, potassium voltage-gated channel subfamily J member 2, potassium inwardly rectifying channel subfamily J member 2
External IDs	OMIM: 600681 MGI: 104744 HomoloGene: 20249 GeneCards: KCNJ2
Gene location (Human) Chr. Chromosome 17 (human)[1] Band 17q24.3 Start 70,168,673 bp[1] End 70,180,044 bp[1]
Gene location (Mouse) Chr. Chromosome 11 (mouse)[2] Band 11 E2|11 75.23 cM Start 110,956,990 bp[2] End 110,967,647 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in inferior ganglion of vagus nerve pons subthalamic nucleus corpus callosum superior vestibular nucleus inferior olivary nucleus body of tongue vastus lateralis muscle deltoid muscle ventral tegmental area Top expressed in superior frontal gyrus lip temporal muscle esophagus upper arm membranous bone maxilla human mandible interventricular septum skeletal muscle tissue More reference expression data BioGPS More reference expression data
Gene ontology Molecular function voltage-gated potassium channel activity involved in cardiac muscle cell action potential repolarization voltage-gated ion channel activity identical protein binding phosphatidylinositol-4,5-bisphosphate binding inward rectifier potassium channel activity G-protein activated inward rectifier potassium channel activity Cellular component integral component of membrane rough endoplasmic reticulum Golgi apparatus membrane intercalated disc T-tubule voltage-gated potassium channel complex plasma membrane dendritic spine integral component of plasma membrane smooth endoplasmic reticulum neuronal cell body dendrite intrinsic component of membrane Biological process cardiac muscle cell action potential regulation of ion transmembrane transport magnesium ion transport cardiac muscle cell action potential involved in contraction ion transport cellular potassium ion homeostasis potassium ion transport regulation of cardiac muscle cell contraction cellular response to mechanical stimulus membrane repolarization during action potential potassium ion transmembrane transport positive regulation of potassium ion transmembrane transport regulation of skeletal muscle contraction via regulation of action potential regulation of resting membrane potential regulation of membrane repolarization relaxation of skeletal muscle regulation of heart rate by cardiac conduction membrane repolarization during cardiac muscle cell action potential protein homotetramerization relaxation of cardiac muscle membrane depolarization during cardiac muscle cell action potential potassium ion import across plasma membrane cardiac conduction Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 3759 16518 Ensembl ENSG00000123700 ENSMUSG00000041695 UniProt P63252 P35561 RefSeq (mRNA) NM_000891 NM_008425 RefSeq (protein) NP_000882 NP_032451 Location (UCSC) Chr 17: 70.17 – 70.18 Mb Chr 11: 110.96 – 110.97 Mb PubMed search [3] [4]
Wikidata
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The K_ir2.1 inward-rectifier potassium channel is a lipid-gated ion channel encoded by the KCNJ2 gene.^[5][6][7][8]

Clinical significance

A defect in this gene is associated with Andersen-Tawil syndrome.^[9]

A mutation in the KCNJ2 gene has also been shown to cause short QT syndrome.^[10]

In research

In neurogenetics, Kir2.1 is used in Drosophila research to inhibit neurons, as overexpression of this channel will hyperpolarize cells.

In optogenetics, a trafficking sequence from Kir2.1 has been added to halorhodopsin to improve its membrane localization. The resulting protein eNpHR3.0 is used in optogenetic research to inhibit neurons with light.^[11]

Expression of Kir2.1 gene in human HEK293 cells induce a transient outward current, creating a steady membrane potential close to the reversal potential of potassium.^[12]

Interactions

Kir2.1 has been shown to interact with:

• DLG4,^[13]
• Interleukin 16,^[14] and
• TRAK2^[15]