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1.A.2.1.2
G-protein enhanced inward rectifier K channel 2, IRK1, IRK2, KCNJ2, KCNJ5, Kir2.1 (Andersen-Tawil Syndrome (ATS-1) protein; the V302M mutation causing the syndrome, alters the G-loop cytoplasmic K conduction pathway) (Bendahhou et al., 2003; Ma et al., 2007). (Blocked by chloroquine which binds in the cytoplasmic pore domain (Rodriguez-Menchaca et al., 2008)). Forms heteromultimers with Kir3.1 and Kir3.4 (Ishihara et al., 2009). A C-terminal domain is critical for the sensitivity of Kir2.1 to cholesterol (Epshtein et al., 2009). Flecainide increases Kir2.1 currents by interacting with cysteine 311, decreasing the polyamine-induced rectification (Caballero et al., 2010).  The inhibitory cholesterol binding site has been identified (Fürst et al. 2014).  Polyamines and Mg2+ block ion flux synergistically (Huang and Kuo 2016). Long polyamines serve a dual role as both blockers and coactivators (with PIP2) of Kir2.1 channels (Xie et al. 2005).  Cytoplasmic domain structures of Kir2.1 and Kir3.1 show sites for modulating gating and rectification (Pegan et al. 2005). Loss-of-function mutations are a rare cause of long QT syndrome (Fodstad et al. 2004).

Accession Number:P63252
Protein Name:Inward rectifier potassium channel 2 aka IRK2
Length:427
Molecular Weight:48288.00
Species:Homo sapiens (Human) [9606]
Number of TMSs:4
Location1 / Topology2 / Orientation3: Membrane1 / Multi-pass membrane protein2
Substrate K+

Cross database links:

Genevestigator: P63252
eggNOG: prNOG10748
HEGENOM: HBG716702
RefSeq: NP_000882.1   
Entrez Gene ID: 3759   
Pfam: PF01007    PF08466   
OMIM: 170390  phenotype
600681  gene
609622  phenotype
KEGG: hsa:3759   

Gene Ontology

GO:0005887 C:integral to plasma membrane
GO:0005242 F:inward rectifier potassium channel activity
GO:0005515 F:protein binding
GO:0006813 P:potassium ion transport

References (10)

[1] “Molecular cloning and expression of a human heart inward rectifier potassium channel.”  Raab-Graham K.F.et.al.   7696590
[2] “Cloning and functional expression of a human gene, hIRK1, encoding the heart inward rectifier K+-channel.”  Wood L.S.et.al.   7590287
[3] “Inwardly rectifying whole cell potassium current in human blood eosinophils.”  Tare M.et.al.   9490857
[4] “Genetic and functional linkage of Kir5.1 and Kir2.1 channel subunits.”  Derst C.et.al.   11240146
[5] “Inward rectifier K+ channel from human heart and brain: cloning and stable expression in a human cell line.”  Ashen M.D.et.al.   7840300
[6] “Global survey of phosphotyrosine signaling identifies oncogenic kinases in lung cancer.”  Rikova K.et.al.   18083107
[7] “Mutations in Kir2.1 cause the developmental and episodic electrical phenotypes of Andersen's syndrome.”  Plaster N.M.et.al.   11371347
[8] “KCNJ2 mutation results in Andersen syndrome with sex-specific cardiac and skeletal muscle phenotypes.”  Andelfinger G.et.al.   12148092
[9] “Functional and clinical characterization of KCNJ2 mutations associated with LQT7 (Andersen syndrome).”  Tristani-Firouzi M.et.al.   12163457
[10] “A novel form of short QT syndrome (SQT3) is caused by a mutation in the KCNJ2 gene.”  Priori S.G.et.al.   15761194
Structure:
6SPZ     

External Searches:

  • Search: DB with
  • BLAST ExPASy (Swiss Institute of Bioinformatics (SIB) BLAST)
  • CDD Search (Conserved Domain Database)
  • Search COGs (Clusters of Orthologous Groups of proteins)
  • 2° Structure (Network Protein Sequence Analysis)

Analyze:

Predict TMSs (Predict number of transmembrane segments)
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FASTA formatted sequence
1:	MGSVRTNRYS IVSSEEDGMK LATMAVANGF GNGKSKVHTR QQCRSRFVKK DGHCNVQFIN 
61:	VGEKGQRYLA DIFTTCVDIR WRWMLVIFCL AFVLSWLFFG CVFWLIALLH GDLDASKEGK 
121:	ACVSEVNSFT AAFLFSIETQ TTIGYGFRCV TDECPIAVFM VVFQSIVGCI IDAFIIGAVM 
181:	AKMAKPKKRN ETLVFSHNAV IAMRDGKLCL MWRVGNLRKS HLVEAHVRAQ LLKSRITSEG 
241:	EYIPLDQIDI NVGFDSGIDR IFLVSPITIV HEIDEDSPLY DLSKQDIDNA DFEIVVILEG 
301:	MVEATAMTTQ CRSSYLANEI LWGHRYEPVL FEEKHYYKVD YSRFHKTYEV PNTPLCSARD 
361:	LAEKKYILSN ANSFCYENEV ALTSKEEDDS ENGVPESTST DTPPDIDLHN QASVPLEPRP 
421:	LRRESEI