Inward rectifier potassium channel 2
Also known as: IRK1, KCNJ2
Function
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. Probably participates in establishing action potential waveform and excitability of neuronal and muscle tissues.
Classification
- Family (Pfam)
- PF01007 IRK, PF17655 IRK_C, PF08466 IRK_N
- InterPro
- Ig_E-set, IRK_C, K_chnl_inward-rec_Kir, K_chnl_inward-rec_Kir2.1, K_chnl_inward-rec_Kir_cyto, K_chnl_inward-rec_Kir_N, Kir_TM
- Functional cluster
- Nucleotide & Amino-Acid Biosynthesis Enzymes
Experimental structures · PDB · 3
A predicted model is available from AlphaFold.
Gene Ontology · 31
- GO:0043197 dendritic spine
- GO:0098978 glutamatergic synapse
- GO:0014704 intercalated disc
- GO:0016020 membrane
- GO:0043025 neuronal cell body
- GO:0005886 plasma membrane
- GO:0045211 postsynaptic membrane
- GO:0030315 T-tubule
- GO:0008076 voltage-gated potassium channel complex
- GO:0042802 identical protein binding
- GO:0005242 inward rectifier potassium channel activity
- GO:0005546 phosphatidylinositol-4,5-bisphosphate binding
- GO:0086008 voltage-gated potassium channel activity involved in cardiac muscle cell action potential repolarization
- GO:0086002 cardiac muscle cell action potential involved in contraction
- GO:0071260 cellular response to mechanical stimulus
- GO:0030007 intracellular potassium ion homeostasis
- GO:0086012 membrane depolarization during cardiac muscle cell action potential
- GO:0086011 membrane repolarization during action potential
- GO:0086013 membrane repolarization during cardiac muscle cell action potential
- GO:1901381 positive regulation of potassium ion transmembrane transport
- GO:1990573 potassium ion import across plasma membrane
- GO:0071805 potassium ion transmembrane transport
- GO:0006813 potassium ion transport
- GO:0051289 protein homotetramerization
- GO:0086004 regulation of cardiac muscle cell contraction
- GO:0086091 regulation of heart rate by cardiac conduction
- GO:0060306 regulation of membrane repolarization
- GO:0060075 regulation of resting membrane potential
- GO:0014861 regulation of skeletal muscle contraction via regulation of action potential
- GO:0055119 relaxation of cardiac muscle
- GO:0090076 relaxation of skeletal muscle
Disease associations
- Andersen-Tawil syndrome MONDO:0008222
- short QT syndrome type 3 MONDO:0012314
- atrial fibrillation, familial, 9 MONDO:0013513
Drugs targeting this protein · 1
- DRONEDARONE HYDROCHLORIDE blocker
Related proteins · sequence + function similarity
- Inward rectifier potassium channel 2 1.00
- Inward rectifier potassium channel 2 1.00
- Inward rectifier potassium channel 2 1.00
- Inward rectifier potassium channel 2 1.00
- Inward rectifier potassium channel 2 1.00
- Inward rectifier potassium channel 2 1.00
- Inward rectifier potassium channel 2 1.00
- Inward rectifier potassium channel 2 0.99
- ATP-sensitive inward rectifier potassium channel 12 0.97
- ATP-sensitive inward rectifier potassium channel 12 0.96
- ATP-sensitive inward rectifier potassium channel 12 0.96
- ATP-sensitive inward rectifier potassium channel 12 0.96
Co-cited proteins · studied together in the literature
- Inward rectifier potassium channel 16 1 shared papers
- ATP-sensitive inward rectifier potassium channel 12 2 shared papers
- Inward rectifier potassium channel 4 1 shared papers
- Inward rectifier potassium channel 2 2 shared papers
- Inward rectifier potassium channel 18 1 shared papers
- Inward rectifier potassium channel 2 2 shared papers
- ATP-sensitive inward rectifier potassium channel 12 1 shared papers
- Inward rectifier potassium channel 2 1 shared papers
- Inward rectifier potassium channel 2 1 shared papers
- Inward rectifier potassium channel 2 1 shared papers
- Inward rectifier potassium channel 2 1 shared papers
- Inward rectifier potassium channel 2 1 shared papers
Literature · 18 cited papers
- Cryo-electron microscopy unveils unique structural features of the human Kir2.1 channel. Sci. Adv. · 2022
- Kir2.6 regulates the surface expression of Kir2.x inward rectifier potassium channels. J. Biol. Chem. · 2011
- Nitric oxide increases cardiac IK1 by nitrosylation of cysteine 76 of Kir2.1 channels. Circ. Res. · 2009
- Corticosteroid-exacerbated symptoms in an Andersen's syndrome kindred. Hum. Mol. Genet. · 2007
- Functional and clinical characterization of a mutation in KCNJ2 associated with Andersen-Tawil syndrome. J. Med. Genet. · 2006
- A Kir2.1 gain-of-function mutation underlies familial atrial fibrillation. Biochem. Biophys. Res. Commun. · 2005
- A novel form of short QT syndrome (SQT3) is caused by a mutation in the KCNJ2 gene. Circ. Res. · 2005
- Functional and clinical characterization of KCNJ2 mutations associated with LQT7 (Andersen syndrome). J. Clin. Invest. · 2002
- KCNJ2 mutation results in Andersen syndrome with sex-specific cardiac and skeletal muscle phenotypes. Am. J. Hum. Genet. · 2002
- Heteromerization of Kir2.x potassium channels contributes to the phenotype of Andersen's syndrome. Proc. Natl. Acad. Sci. U.S.A. · 2002
- Mutations in Kir2.1 cause the developmental and episodic electrical phenotypes of Andersen's syndrome. Cell · 2001
- Genetic and functional linkage of Kir5.1 and Kir2.1 channel subunits. FEBS Lett. · 2001
- … and 6 more in the literature graph
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