P52189 (IRK4_MOUSE) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names

Recommended name:
Inward rectifier potassium channel 4

Alternative name(s):
Inward rectifier K(+) channel Kir2.3
Short name=IRK-3
Potassium channel, inwardly rectifying subfamily J member 4

Gene names

Name:	Kcnj4
Synonyms:	Irk3

Organism

Mus musculus (Mouse)

Taxonomic identifier

10090 [NCBI]

Taxonomic lineage

Eukaryota › Metazoa › Chordata › Craniata › Vertebrata › Euteleostomi › Mammalia › Eutheria › Euarchontoglires › Glires › Rodentia › Sciurognathi › Muroidea › Muridae › Murinae › Mus › Mus

Protein attributes

Sequence length	445 AA.
Sequence status	Complete.
Protein existence	Evidence at transcript level

General annotation (Comments)

Function	This receptor is controlled by G proteins. 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 and cesium By similarity.
Subunit structure	Homomultimeric and heteromultimeric association with Kir2.1, resulting in an enhanced G-protein-induced current. Association, via its PDZ-recognition domain, with LIN7A, LIN7B, LIN7C, DLG1, CASK and APBA1 plays a key role in its localization and trafficking By similarity.
Subcellular location	Membrane; Multi-pass membrane protein.
Tissue specificity	Highly expressed in the forebrain, moderately in skeletal muscle.
Developmental stage	Expression increases between day 2 to 45 and is then stable from day 45 to 120.
Sequence similarities	Belongs to the inward rectifier-type potassium channel (TC 1.A.2.1) family. KCNJ4 subfamily. [View classification]

Ontologies

Keywords
Biological process	Ion transport Potassium transport Transport
Cellular component	Membrane
Domain	Transmembrane Transmembrane helix
Ligand	Potassium
Molecular function	Ionic channel Voltage-gated channel
Technical term	Complete proteome Reference proteome
Gene Ontology (GO)
Cellular component	integral to membrane Inferred from electronic annotation. Source: UniProtKB-KW
Molecular function	inward rectifier potassium channel activity Inferred from electronic annotation. Source: InterPro
Complete GO annotation...

Sequence annotation (Features)

	Feature key	Position(s)	Length	Description	Graphical view	Feature identifier
Molecule processing
	Chain	1 – 445	445	Inward rectifier potassium channel 4		PRO_0000154932
Regions
	Topological domain	1 – 55	55	Cytoplasmic By similarity
	Transmembrane	56 – 80	25	Helical; Name=M1; By similarity
	Topological domain	81 – 119	39	Extracellular By similarity
	Intramembrane	120 – 131	12	Helical; Pore-forming; Name=H5; By similarity
	Intramembrane	132 – 138	7	Pore-forming; By similarity
	Topological domain	139 – 147	9	Extracellular By similarity
	Transmembrane	148 – 169	22	Helical; Name=M2; By similarity
	Topological domain	170 – 445	276	Cytoplasmic By similarity
	Motif	133 – 138	6	Selectivity filter By similarity
	Motif	443 – 445	3	PDZ-binding Potential
	Compositional bias	361 – 367	7	Poly-Pro
	Compositional bias	382 – 389	8	Poly-Glu
	Compositional bias	390 – 398	9	Poly-Ala
Sites
	Site	163	1	Role in the control of polyamine-mediated channel gating and in the blocking by intracellular magnesium By similarity
Experimental info
	Sequence conflict	79	1	W → C in AAA53241. Ref.2
	Sequence conflict	86	1	D → E in AAA53241. Ref.2
	Sequence conflict	96	1	V → A in AAA53241. Ref.2
	Sequence conflict	105	1	E → A in AAA53241. Ref.2
	Sequence conflict	239	1	R → G in AAA53241. Ref.2
	Sequence conflict	444	1	R → A in AAA53241. Ref.2

Sequences

	Sequence		Length	Mass (Da)
	P52189 [UniParc]. Last modified October 1, 1996. Version 1. Checksum: 09C9E889CC8E0DF3	FASTA	445	49,899
	10 20 30 40 50 60 MHGHNRNGQA HVPRRKRRNR FVKKNGQCNV YFANLSNKSQ RYMADIFTTC VDTRWRYMLM 70 80 90 100 110 120 IFSAAFLVSW LFFGLLFWWI AFFHGDLEAS PSVPAVGGPG GNGGESPNAP KPCIMHVNGF 130 140 150 160 170 180 LGAFLFSVET QTTIGYGFRC VTEECPLAVI AVVVQSIVGC VIDSFMIGTI MAKMARPKKR 190 200 210 220 230 240 AQTLLFSHHA VISVRDGKLC LMWRVGNLRK SHIVEAHVRA QLIKPYMTQE GEYLPLDQRD 250 260 270 280 290 300 LNVGYDIGLD RIFLVSPIII VHEIDEDSPL YGMGKEELES EDFEIVVILE GMVEATAMTT 310 320 330 340 350 360 QARSSYLASE ILWGHRFEPV VFEEKSHYKV DYSRFHKTYE VAGTPCCSAR ELQESKITVL 370 380 390 400 410 420 PAPPPPPSAF CYENELALMS QEEEEMEEEA AAAAAVAAGL GLEAGSKEEA GIIRMLEFGS 430 440 HLDLERMQAA TLPLDNISYR RESRI

References

[1]	"Molecular cloning and functional expression of a novel brain-specific inward rectifier potassium channel." Morishige K., Takahashi N., Jahangir A., Yamada M., Koyama H., Zanelli J.S., Kurachi Y. FEBS Lett. 346:251-256(1994) [PubMed: 8013643] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA]. Tissue: Brain.
[2]	"Cloning provides evidence for a family of inward rectifier and G-protein coupled K+ channels in the brain." Lesage F., Duprat F., Fink M., Guillemare E., Coppola T., Lazdunski M., Hugnot J.-P. FEBS Lett. 353:37-42(1994) [PubMed: 7926018] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA]. Tissue: Brain.
+	Additional computationally mapped references.

Cross-references

Sequence databases
EMBL GenBank DDBJ	U11075 mRNA. Translation: AAA53241.1. S71382 mRNA. Translation: AAB31087.1.
IPI	IPI00123672.
PIR	S45713.
UniGene	Mm.140760.
3D structure databases
ProteinModelPortal	P52189.
SMR	P52189. Positions 18-356.
ModBase	Search...
Protein-protein interaction databases
IntAct	P52189. 1 interaction.
MINT	MINT-103836.
STRING	P52189.
PTM databases
PhosphoSite	P52189.
Proteomic databases
PRIDE	P52189.
Protocols and materials databases
StructuralBiologyKnowledgebase	Search...
Organism-specific databases
MGI	MGI:104743. Kcnj4.
Phylogenomic databases
eggNOG	maNOG10942.
HOGENOM	HBG716702.
HOVERGEN	HBG006178.
InParanoid	P52189.
OrthoDB	EOG40GCR0.
Gene expression databases
ArrayExpress	P52189.
Bgee	P52189.
Genevestigator	P52189.
GermOnline	ENSMUSG00000044216. Mus musculus.
Family and domain databases
InterPro	IPR014756. Ig_E-set. IPR016449. K_chnl_inward-rec_Kir. IPR001838. K_chnl_inward-rec_Kir-like. IPR003273. K_chnl_inward-rec_Kir2.3. IPR013521. K_chnl_inward-rec_Kir_Cr2. IPR013518. K_chnl_inward-rec_Kir_cyto. [Graphical view]
Gene3D	G3DSA:2.60.40.1400. IR_K+channel_cytopl. 1 hit.
PANTHER	PTHR11767. K+channel_IR. 1 hit. PTHR11767:SF13. KIR23_channel. 1 hit.
Pfam	PF01007. IRK. 1 hit. [Graphical view]
PIRSF	PIRSF005465. GIRK_kir. 1 hit.
PRINTS	PR01326. KIR23CHANNEL. PR01320. KIRCHANNEL.
SUPFAM	SSF81296. Ig_E-set. 1 hit.
ProtoNet	Search...
Other
SOURCE	Search...

Entry information

Entry name

IRK4_MOUSE

Accession

Primary (citable) accession number: P52189

Entry history

Integrated into UniProtKB/Swiss-Prot:	October 1, 1996
Last sequence update:	October 1, 1996
Last modified:	January 25, 2012
This is version 94 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Chordata Protein Annotation Program