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Protein

Inward rectifier potassium channel 18

Gene

KCNJ18

Organism
Homo sapiens (Human)
Status
Reviewed-Annotation score: Annotation score: 5 out of 5-Experimental evidence at protein leveli

Functioni

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.1 Publication

GO - Molecular functioni

  • inward rectifier potassium channel activity Source: UniProtKB

GO - Biological processi

Complete GO annotation...

Keywords - Molecular functioni

Ion channel, Voltage-gated channel

Keywords - Biological processi

Ion transport, Potassium transport, Transport

Keywords - Ligandi

Potassium

Names & Taxonomyi

Protein namesi
Recommended name:
Inward rectifier potassium channel 18
Alternative name(s):
Inward rectifier K(+) channel Kir2.6
Potassium channel, inwardly rectifying subfamily J member 18
Gene namesi
Name:KCNJ18
OrganismiHomo sapiens (Human)
Taxonomic identifieri9606 [NCBI]
Taxonomic lineageiEukaryotaMetazoaChordataCraniataVertebrataEuteleostomiMammaliaEutheriaEuarchontogliresPrimatesHaplorrhiniCatarrhiniHominidaeHomo
Proteomesi
  • UP000005640 Componenti: Chromosome 17

Organism-specific databases

HGNCiHGNC:39080. KCNJ18.

Subcellular locationi

Topology

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Topological domaini1 – 84CytoplasmicSequence analysisAdd BLAST84
Transmembranei85 – 105HelicalSequence analysisAdd BLAST21
Topological domaini106 – 156ExtracellularSequence analysisAdd BLAST51
Transmembranei157 – 177HelicalSequence analysisAdd BLAST21
Topological domaini178 – 433CytoplasmicSequence analysisAdd BLAST256

GO - Cellular componenti

  • integral component of plasma membrane Source: GO_Central
  • plasma membrane Source: UniProtKB
Complete GO annotation...

Keywords - Cellular componenti

Cell membrane, Membrane

Pathology & Biotechi

Involvement in diseasei

Thyrotoxic periodic paralysis 2 (TTPP2)1 Publication
Disease susceptibility is associated with variations affecting the gene represented in this entry.
Disease descriptionA sporadic muscular disorder characterized by episodic weakness and hypokalemia during a thyrotoxic state. It is clinically similar to hereditary hypokalemic periodic paralysis, except for the fact that hyperthyroidism is an absolute requirement for disease manifestation. The disease presents with recurrent episodes of acute muscular weakness of the four extremities that vary in severity from paresis to complete paralysis. Attacks are triggered by ingestion of a high carbohydrate load or strenuous physical activity followed by a period of rest. Thyrotoxic periodic paralysis can occur in association with any cause of hyperthyroidism, but is most commonly associated with Graves disease.
See also OMIM:613239
Feature keyPosition(s)DescriptionActionsGraphical viewLength
Natural variantiVAR_063286140T → M in TTPP2. 1 PublicationCorresponds to variant rs527236152dbSNPEnsembl.1
Natural variantiVAR_063287205R → H in TTPP2; hypermorphic; longer time required for half-maximal current degradation. 1 PublicationCorresponds to variant rs672601244dbSNPEnsembl.1
Natural variantiVAR_063288354T → M in TTPP2; small decrease in current density. 1 PublicationCorresponds to variant rs527236158dbSNPEnsembl.1
Natural variantiVAR_063289366K → R in TTPP2; hypermorphic; longer time required for half-maximal current degradation. 1 PublicationCorresponds to variant rs527236159dbSNPEnsembl.1

Mutagenesis

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Mutagenesisi354T → E: Decreases the single-channel open probability (Po) without altering its conductance. 1 Publication1

Keywords - Diseasei

Disease mutation

Organism-specific databases

DisGeNETi100134444.
MalaCardsiKCNJ18.
MIMi613239. phenotype.
OpenTargetsiENSG00000260458.
Orphaneti79102. Thyrotoxic periodic paralysis.

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
ChainiPRO_00003951711 – 433Inward rectifier potassium channel 18Add BLAST433

Amino acid modifications

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Modified residuei75S-nitrosocysteineBy similarity1

Post-translational modificationi

Probably phosphorylated by PKC; decreases single-channel open probability.1 Publication

Keywords - PTMi

Phosphoprotein, S-nitrosylation

Proteomic databases

PaxDbiB7U540.
PRIDEiB7U540.

PTM databases

iPTMnetiB7U540.
PhosphoSitePlusiB7U540.

Expressioni

Tissue specificityi

Specifically expressed in skeletal muscle.1 Publication

Inductioni

Up-regulated by triiodothyronine.1 Publication

Organism-specific databases

HPAiHPA027021.

Interactioni

Protein-protein interaction databases

STRINGi9606.ENSP00000328150.

Structurei

3D structure databases

ProteinModelPortaliB7U540.
SMRiB7U540.
ModBaseiSearch...
MobiDBiSearch...

Family & Domainsi

Sequence similaritiesi

Keywords - Domaini

Transmembrane, Transmembrane helix

Phylogenomic databases

eggNOGiKOG3827. Eukaryota.
ENOG410XQ62. LUCA.
GeneTreeiENSGT00760000118842.
HOVERGENiHBG006178.
InParanoidiB7U540.
KOiK19468.
OMAiHQHEMSI.
OrthoDBiEOG091G08HC.
PhylomeDBiB7U540.

Family and domain databases

Gene3Di2.60.40.1400. 1 hit.
InterProiIPR014756. Ig_E-set.
IPR016449. K_chnl_inward-rec_Kir.
IPR003272. K_chnl_inward-rec_Kir2.2.
IPR013518. K_chnl_inward-rec_Kir_cyto.
IPR013673. K_chnl_inward-rec_Kir_N.
[Graphical view]
PANTHERiPTHR11767. PTHR11767. 1 hit.
PTHR11767:SF14. PTHR11767:SF14. 1 hit.
PfamiPF01007. IRK. 1 hit.
PF08466. IRK_N. 1 hit.
[Graphical view]
PRINTSiPR01325. KIR22CHANNEL.
PR01320. KIRCHANNEL.
SUPFAMiSSF81296. SSF81296. 1 hit.

Sequencei

Sequence statusi: Complete.

B7U540-1 [UniParc]FASTAAdd to basket

« Hide

        10         20         30         40         50
MTAASRANPY SIVSLEEDGL HLVTMSGANG FGNGKVHTRR RCRNRFVKKN
60 70 80 90 100
GQCNIAFANM DEKSQRYLAD MFTTCVDIRW RYMLLIFSLA FLASWLLFGV
110 120 130 140 150
IFWVIAVAHG DLEPAEGHGR TPCVMQVHGF MAAFLFSIET QTTIGYGLRC
160 170 180 190 200
VTEECLVAVF MVVAQSIVGC IIDSFMIGAI MAKMARPKKR AQTLLFSHNA
210 220 230 240 250
VVALRDGKLC LMWRVGNLRK SHIVEAHVRA QLIKPRVTEE GEYIPLDQID
260 270 280 290 300
IDVGFDKGLD RIFLVSPITI LHEIDEASPL FGISRQDLET DDFEIVVILE
310 320 330 340 350
GMVEATAMTT QARSSYLANE ILWGHRFEPV LFEEKNQYKI DYSHFHKTYE
360 370 380 390 400
VPSTPRCSAK DLVENKFLLP SANSFCYENE LAFLSRDEED EADGDQDGRS
410 420 430
RDGLSPQARH DFDRLQAGGG VLEQRPYRRG SEI
Length:433
Mass (Da):48,880
Last modified:October 14, 2015 - v3
Checksum:i284FC956E6139DD0
GO

Experimental Info

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Sequence conflicti6R → Q in ACJ64506 (PubMed:20074522).1
Sequence conflicti29N → K in ACJ64506 (PubMed:20074522).1
Sequence conflicti39 – 40RR → QH in ACJ64506 (PubMed:20074522).2
Sequence conflicti192Q → H in ACJ64506 (PubMed:20074522).1
Sequence conflicti249I → V in ACJ64506 (PubMed:20074522).1
Sequence conflicti281F → L in ACJ64506 (PubMed:20074522).1
Sequence conflicti338 – 342YKIDY → FKIDH in ACJ64506 (PubMed:20074522).5

Natural variant

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Natural variantiVAR_063286140T → M in TTPP2. 1 PublicationCorresponds to variant rs527236152dbSNPEnsembl.1
Natural variantiVAR_063287205R → H in TTPP2; hypermorphic; longer time required for half-maximal current degradation. 1 PublicationCorresponds to variant rs672601244dbSNPEnsembl.1
Natural variantiVAR_063288354T → M in TTPP2; small decrease in current density. 1 PublicationCorresponds to variant rs527236158dbSNPEnsembl.1
Natural variantiVAR_063289366K → R in TTPP2; hypermorphic; longer time required for half-maximal current degradation. 1 PublicationCorresponds to variant rs527236159dbSNPEnsembl.1

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
FJ434338 mRNA. Translation: ACJ64506.2.
AC233702 Genomic DNA. No translation available.
CCDSiCCDS74015.1.
RefSeqiNP_001181887.2. NM_001194958.2.
UniGeneiHs.200629.

Genome annotation databases

EnsembliENST00000567955; ENSP00000457807; ENSG00000260458.
GeneIDi100134444.
KEGGihsa:100134444.
UCSCiuc032exz.1. human.

Keywords - Coding sequence diversityi

Polymorphism

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
FJ434338 mRNA. Translation: ACJ64506.2.
AC233702 Genomic DNA. No translation available.
CCDSiCCDS74015.1.
RefSeqiNP_001181887.2. NM_001194958.2.
UniGeneiHs.200629.

3D structure databases

ProteinModelPortaliB7U540.
SMRiB7U540.
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

STRINGi9606.ENSP00000328150.

PTM databases

iPTMnetiB7U540.
PhosphoSitePlusiB7U540.

Proteomic databases

PaxDbiB7U540.
PRIDEiB7U540.

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Genome annotation databases

EnsembliENST00000567955; ENSP00000457807; ENSG00000260458.
GeneIDi100134444.
KEGGihsa:100134444.
UCSCiuc032exz.1. human.

Organism-specific databases

CTDi100134444.
DisGeNETi100134444.
GeneCardsiKCNJ18.
HGNCiHGNC:39080. KCNJ18.
HPAiHPA027021.
MalaCardsiKCNJ18.
MIMi613236. gene.
613239. phenotype.
neXtProtiNX_B7U540.
OpenTargetsiENSG00000260458.
Orphaneti79102. Thyrotoxic periodic paralysis.
GenAtlasiSearch...

Phylogenomic databases

eggNOGiKOG3827. Eukaryota.
ENOG410XQ62. LUCA.
GeneTreeiENSGT00760000118842.
HOVERGENiHBG006178.
InParanoidiB7U540.
KOiK19468.
OMAiHQHEMSI.
OrthoDBiEOG091G08HC.
PhylomeDBiB7U540.

Miscellaneous databases

GenomeRNAii100134444.
PROiB7U540.
SOURCEiSearch...

Family and domain databases

Gene3Di2.60.40.1400. 1 hit.
InterProiIPR014756. Ig_E-set.
IPR016449. K_chnl_inward-rec_Kir.
IPR003272. K_chnl_inward-rec_Kir2.2.
IPR013518. K_chnl_inward-rec_Kir_cyto.
IPR013673. K_chnl_inward-rec_Kir_N.
[Graphical view]
PANTHERiPTHR11767. PTHR11767. 1 hit.
PTHR11767:SF14. PTHR11767:SF14. 1 hit.
PfamiPF01007. IRK. 1 hit.
PF08466. IRK_N. 1 hit.
[Graphical view]
PRINTSiPR01325. KIR22CHANNEL.
PR01320. KIRCHANNEL.
SUPFAMiSSF81296. SSF81296. 1 hit.
ProtoNetiSearch...

Entry informationi

Entry nameiKCJ18_HUMAN
AccessioniPrimary (citable) accession number: B7U540
Secondary accession number(s): A0A075B742
Entry historyi
Integrated into UniProtKB/Swiss-Prot: July 13, 2010
Last sequence update: October 14, 2015
Last modified: November 2, 2016
This is version 63 of the entry and version 3 of the sequence. [Complete history]
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programChordata Protein Annotation Program
DisclaimerAny medical or genetic information present in this entry is provided for research, educational and informational purposes only. It is not in any way intended to be used as a substitute for professional medical advice, diagnosis, treatment or care.

Miscellaneousi

Keywords - Technical termi

Complete proteome, Reference proteome

Documents

  1. Human chromosome 17
    Human chromosome 17: entries, gene names and cross-references to MIM
  2. Human entries with polymorphisms or disease mutations
    List of human entries with polymorphisms or disease mutations
  3. Human polymorphisms and disease mutations
    Index of human polymorphisms and disease mutations
  4. MIM cross-references
    Online Mendelian Inheritance in Man (MIM) cross-references in UniProtKB/Swiss-Prot
  5. SIMILARITY comments
    Index of protein domains and families

Similar proteinsi

Links to similar proteins from the UniProt Reference Clusters (UniRef) at 100%, 90% and 50% sequence identity:
100%UniRef100 combines identical sequences and sub-fragments with 11 or more residues from any organism into one UniRef entry.
90%UniRef90 is built by clustering UniRef100 sequences that have at least 90% sequence identity to, and 80% overlap with, the longest sequence (a.k.a seed sequence).
50%UniRef50 is built by clustering UniRef90 seed sequences that have at least 50% sequence identity to, and 80% overlap with, the longest sequence in the cluster.