Kir2.1

Potassium channel, inwardly rectifying subfamily J, member 2

PDB rendering based on 1u4f.

Available structures

Ortholog search: PDBe, RCSB

List of PDB id codes
1u4f, 2gix

Identifiers

Symbols

KCNJ2 ; ATFB9; HHBIRK1; HHIRK1; IRK1; KIR2.1; LQT7; SQT3

External IDs

OMIM: 600681 MGI: 104744 HomoloGene: 20249 IUPHAR: 430 GeneCards: KCNJ2 Gene

Gene ontology
Molecular function	• inward rectifier potassium channel activity • phosphatidylinositol-4,5-bisphosphate binding • identical protein binding • voltage-gated potassium channel activity involved in cardiac muscle cell action potential repolarization
Cellular component	• smooth endoplasmic reticulum • rough endoplasmic reticulum • Golgi apparatus • plasma membrane • integral component of plasma membrane • voltage-gated potassium channel complex • intercalated disc • T-tubule • intrinsic component of membrane • neuronal cell body • dendritic spine
Biological process	• potassium ion transport • synaptic transmission • potassium ion import • regulation of skeletal muscle contraction via regulation of action potential • magnesium ion transport • cellular potassium ion homeostasis • protein homotetramerization • relaxation of cardiac muscle • regulation of resting membrane potential • regulation of membrane repolarization • cellular response to mechanical stimulus • potassium ion transmembrane transport • cardiac muscle cell action potential involved in contraction • membrane repolarization during action potential • membrane depolarization during cardiac muscle cell action potential • membrane repolarization during cardiac muscle cell action potential • regulation of heart rate by cardiac conduction • relaxation of skeletal muscle • positive regulation of potassium ion transmembrane transport
Sources: Amigo / QuickGO

RNA expression pattern

More reference expression data

Orthologs

Species

Human

Mouse

RefSeq (mRNA)

RefSeq (protein)

Location (UCSC)

Chr 17:
70.17 – 70.18 Mb

Chr 11:
111.07 – 111.08 Mb

PubMed search

The K_ir2.1 inward-rectifier potassium ion channel is encoded by the KCNJ2 gene.^[1]^[2]^[3]

Clinical significance

A defect in this gene is associated with Andersen-Tawil syndrome.^[4]

A mutation in the KCNJ2 gene has also been shown to cause short QT syndrome.^[5]

In research

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.^[6]

Interactions

Kir2.1 has been shown to interact with:

References

↑ Raab-Graham KF, Radeke CM, Vandenberg CA (1994). "Molecular cloning and expression of a human heart inward rectifier potassium channel". NeuroReport 5 (18): 2501–5. doi:10.1097/00001756-199412000-00024. PMID 7696590.
↑ Derst C, Karschin C, Wischmeyer E, Hirsch JR, Preisig-Müller R, Rajan S, Engel H, Grzeschik K, Daut J, Karschin A (2001). "Genetic and functional linkage of Kir5.1 and Kir2.1 channel subunits". FEBS Lett. 491 (3): 305–11. doi:10.1016/S0014-5793(01)02202-5. PMID 11240146.
↑ Kubo Y, Adelman JP, Clapham DE, Jan LY, Karschin A, Kurachi Y, Lazdunski M, Nichols CG, Seino S, Vandenberg CA (2005). "International Union of Pharmacology. LIV. Nomenclature and molecular relationships of inwardly rectifying potassium channels". Pharmacol. Rev. 57 (4): 509–26. doi:10.1124/pr.57.4.11. PMID 16382105.
↑ Donaldson MR, Yoon G, Fu YH, Ptacek LJ (2004). "Andersen-Tawil syndrome: a model of clinical variability, pleiotropy, and genetic heterogeneity". Ann. Med. 36 Suppl 1: 92–7. doi:10.1080/17431380410032490. PMID 15176430.
↑ Priori SG, Pandit SV, Rivolta I, Berenfeld O, Ronchetti E, Dhamoon A, Napolitano C, Anumonwo J, di Barletta MR, Gudapakkam S, Bosi G, Stramba-Badiale M, Jalife J (April 2005). "A novel form of short QT syndrome (SQT3) is caused by a mutation in the KCNJ2 gene". Circ. Res. 96 (7): 800–7. doi:10.1161/01.RES.0000162101.76263.8c. PMID 15761194.
↑ Gradinaru V, Zhang F, Ramakrishnan C, Mattis J, Prakash R, Diester I, Goshen I, Thompson KR, Deisseroth K (April 2010). "Molecular and cellular approaches for diversifying and extending optogenetics". Cell 141 (1): 154–65. doi:10.1016/j.cell.2010.02.037. PMID 20303157.
↑ Nehring RB, Wischmeyer E, Döring F, Veh RW, Sheng M, Karschin A (2000). "Neuronal inwardly rectifying K(+) channels differentially couple to PDZ proteins of the PSD-95/SAP90 family". J. Neurosci. 20 (1): 156–62. PMID 10627592.
↑ Kurschner C, Yuzaki M (1999). "Neuronal interleukin-16 (NIL-16): a dual function PDZ domain protein". J. Neurosci. 19 (18): 7770–80. PMID 10479680.
↑ Grishin A, Li H, Levitan ES, Zaks-Makhina E (2006). "Identification of gamma-aminobutyric acid receptor-interacting factor 1 (TRAK2) as a trafficking factor for the K+ channel Kir2.1". J. Biol. Chem. 281 (40): 30104–11. doi:10.1074/jbc.M602439200. PMID 16895905.

External links

GeneReviews/NCBI/NIH/UW entry on Andersen-Tawil syndrome
OMIM entries on Anderson-Tawil syndrome
KCNJ2 protein, human at the US National Library of Medicine Medical Subject Headings (MeSH)
Kir2.1 channel at the US National Library of Medicine Medical Subject Headings (MeSH)

PDB gallery

1u4f: Crystal Structure of Cytoplasmic Domains of IRK1 (Kir2.1) channel

2gix: Cytoplasmic Domain Structure of Kir2.1 containing Andersen's Mutation R218Q and Rescue Mutation T309K

Membrane transport protein: ion channels (TC 1A)

Ca²⁺: Calcium channel

Ligand-gated	Inositol trisphosphate receptor 1 2 3 Ryanodine receptor 1 2 3

Voltage-gated	L-type/Ca_vα 1.1 1.2 1.3 1.4 N-type/Ca_vα2.2 P-type/Ca_vα 2.1 Q-type/Ca_vα2.1 R-type/Ca_vα2.3 T-type/Ca_vα 3.1 3.2 3.3 α₂δ-subunits 1 2 β-subunits β1 β2 β3 β4 γ-subunits γ1 γ2 γ3 γ4 Cation channels of sperm 1 2 3 4 Two-pore channel 1 2

Na⁺: Sodium channel

Constitutively active	Epithelial sodium channel α β γ δ

Proton-gated	Amiloride-sensitive cation channel 1 2 3 4

Voltage-gated	Na_vα 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 7A Na_vβ 1 2 3 4

K⁺: Potassium channel

Calcium-activated	BK channel α1 β1 β2 β3 β4 SK channel SK1 SK2 SK3 IK channel IK1 K_Ca 1.1 2.1 2.2 2.3 3.1 4.1 4.2 5.1

Inward-rectifier	K_ATP K_ir 1.1 2.1 2.2 2.3 2.4 2.6 GIRK/K_ir 3.1 3.2 3.3 3.4 K_ir 4.1 4.2 5.1 6.1 6.2 7.1

Tandem pore domain	K2P 1 2 3 4 5 6 7 9 10 12 13 15 16 17 18

Voltage-gated	K_vα1-6 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 2.1 2.2 3.1 3.2 3.3 3.4 4.1 4.2 4.3 5.1 6.1 6.2 6.3 6.4 K_vα7-12 7.1 7.2 7.3 7.4 7.5 8.1 8.2 9.1 9.2 9.3 10.1 10.2 11.1/hERG 11.2 11.3 12.1 12.2 12.3 K_vβ 1 2 3 KCNIP 1 2 3 4 minK/ISK minK/ISK-like MiRP 1 2 3 Shaker gene

Miscellaneous

Cl⁻: Chloride channel	Calcium-activated chloride channels Anoctamin ANO1 Bestrophin 1 2 Chloride Channel Accessory 1 2 3 4 CFTR CLCN 1 2 3 4 5 6 7 KA KB CLIC 1 2 3 4 5 6 L1 CLNS 1A 1B

H⁺: Proton channel	HVCN1

M⁺: CNG cation channel	α 1 2 3 4 β 1 2 3 HCN FC 1 2 3 4

M⁺: TRP cation channel	TRPA (1) TRPC 1 2 3 4 4AP 5 6 7 TRPM 1 2 3 4 5 6 7 8 TRPML 1 2 3 TRPN TRPP 1 2 TRPV 1 2 3 4 5 6

H₂O (+ solutes): Porin	Aquaporin 0 1 2 3 4 5 6 7 8 9 Voltage-dependent anion channel 1 2 3 General bacterial porin family

Cytoplasm: Gap junction	Connexin: A GJA1 GJA3 GJA4 GJA5 GJA8 GJA9 GJA10 B GJB1 GJB2 GJB3 GJB4 GJB5 GJB6 GJB7 C GJC1 GJC2 GJC3 D GJD2 GJD3 GJD4) Innexin

By gating mechanism

Ion channel class	Ligand-gated Light-gated Voltage-gated Stretch-activated

see also disorders

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