Skip Header

You are using a version of browser that may not display all the features of this website. Please consider upgrading your browser.
Protein

Inward rectifier potassium channel 18

Gene

KCNJ18

Organism
Homo sapiens (Human)
Status
Reviewed-Annotation score: -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.2 Publications

GO - Molecular functioni

  • inward rectifier potassium channel activity Source: UniProtKB

GO - Biological processi

  • potassium ion import Source: GO_Central
  • regulation of ion transmembrane transport Source: UniProtKB-KW

Keywordsi

Molecular functionIon channel, Voltage-gated channel
Biological processIon transport, Potassium transport, Transport
LigandPotassium

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

EuPathDBiHostDB:ENSG00000260458.3
HGNCiHGNC:39080 KCNJ18
MIMi613236 gene
neXtProtiNX_B7U540

Subcellular locationi

Extracellular region or secreted Cytosol Plasma membrane Cytoskeleton Lysosome Endosome Peroxisome ER Golgi apparatus Nucleus Mitochondrion Manual annotation Automatic computational assertionGraphics by Christian Stolte; Source: COMPARTMENTS

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

Keywords - Cellular componenti

Cell membrane, Membrane

Pathology & Biotechi

Involvement in diseasei

Thyrotoxic periodic paralysis 2 (TTPP2)4 Publications
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_079833126 – 344Missing in TTPP2; abolishes potassium inward and outward currents density. 2 PublicationsAdd BLAST219
Natural variantiVAR_063286140T → M in TTPP2. 1 PublicationCorresponds to variant dbSNP:rs527236152EnsemblClinVar.1
Natural variantiVAR_079834168V → M in TTPP2; unknown pathological significance; decreases potassium inward and outward currents density; reduces cell surface abundance; reduces open propability; dominant negatif mutation. 1 PublicationCorresponds to variant dbSNP:rs527236154EnsemblClinVar.1
Natural variantiVAR_063287205R → H in TTPP2; hypermorphic; longer time required for half-maximal current degradation. 1 PublicationCorresponds to variant dbSNP:rs672601244EnsemblClinVar.1
Natural variantiVAR_063288354T → M in TTPP2; small decrease in current density. 1 PublicationCorresponds to variant dbSNP:rs527236158EnsemblClinVar.1
Natural variantiVAR_079838360K → T in TTPP2; abolishes potassium inward and outward currents density. 2 Publications1
Natural variantiVAR_063289366K → R in TTPP2; hypermorphic; longer time required for half-maximal current degradation. 1 PublicationCorresponds to variant dbSNP:rs527236159EnsemblClinVar.1
Natural variantiVAR_079839388E → K in TTPP2; reduces potassium inward and outward currents density. 2 Publications1

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

Post-translational modificationi

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

Keywords - PTMi

Phosphoprotein

Proteomic databases

PRIDEiB7U540
ProteomicsDBi6260

PTM databases

iPTMnetiB7U540
PhosphoSitePlusiB7U540

Expressioni

Tissue specificityi

Specifically expressed in skeletal muscle.1 Publication

Inductioni

Up-regulated by triiodothyronine.1 Publication

Gene expression databases

BgeeiENSG00000260458 Expressed in 12 organ(s), highest expression level in skin of abdomen

Organism-specific databases

HPAiHPA027021

Interactioni

Protein-protein interaction databases

IntActiB7U540, 2 interactors

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
OMAiNNMEDKP
OrthoDBiEOG091G08HC
PhylomeDBiB7U540

Family and domain databases

Gene3Di2.60.40.1400, 1 hit
InterProiView protein in InterPro
IPR014756 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
PANTHERiPTHR11767 PTHR11767, 1 hit
PTHR11767:SF14 PTHR11767:SF14, 1 hit
PfamiView protein in Pfam
PF01007 IRK, 1 hit
PF08466 IRK_N, 1 hit
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 conflicti192Q → H in ACJ64506 (PubMed:20074522).1
Sequence conflicti192Q → H in AMQ11134 (PubMed:27008341).1
Sequence conflicti192Q → H in AMQ11135 (PubMed:27008341).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_07983039 – 40RR → QH2 Publications2
Natural variantiVAR_07983143R → C Found in a patient with sporadic periodic paralysis; unknown pathological significance; decreases potassium inward and outward currents density; reduces cell surface abundance; reduces conductance; dominant negatif mutation. 1 PublicationCorresponds to variant dbSNP:rs527236151EnsemblClinVar.1
Natural variantiVAR_07983256A → E1 Publication1
Natural variantiVAR_079833126 – 344Missing in TTPP2; abolishes potassium inward and outward currents density. 2 PublicationsAdd BLAST219
Natural variantiVAR_063286140T → M in TTPP2. 1 PublicationCorresponds to variant dbSNP:rs527236152EnsemblClinVar.1
Natural variantiVAR_079834168V → M in TTPP2; unknown pathological significance; decreases potassium inward and outward currents density; reduces cell surface abundance; reduces open propability; dominant negatif mutation. 1 PublicationCorresponds to variant dbSNP:rs527236154EnsemblClinVar.1
Natural variantiVAR_079835169G → R Found in a patient with hypokalemic periodic paralysis without hyperthyroidism; reduces potassium inward and outward currents density. 1 Publication1
Natural variantiVAR_079836200A → P Found in a patient with sporadic periodic paralysis; unknown pathological significance; abolishes potassium inward and outward currents density; reduces cell surface abundance. 1 PublicationCorresponds to variant dbSNP:rs527236155EnsemblClinVar.1
Natural variantiVAR_063287205R → H in TTPP2; hypermorphic; longer time required for half-maximal current degradation. 1 PublicationCorresponds to variant dbSNP:rs672601244EnsemblClinVar.1
Natural variantiVAR_079837249I → V2 Publications1
Natural variantiVAR_063288354T → M in TTPP2; small decrease in current density. 1 PublicationCorresponds to variant dbSNP:rs527236158EnsemblClinVar.1
Natural variantiVAR_079838360K → T in TTPP2; abolishes potassium inward and outward currents density. 2 Publications1
Natural variantiVAR_063289366K → R in TTPP2; hypermorphic; longer time required for half-maximal current degradation. 1 PublicationCorresponds to variant dbSNP:rs527236159EnsemblClinVar.1
Natural variantiVAR_079839388E → K in TTPP2; reduces potassium inward and outward currents density. 2 Publications1

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
FJ434338 mRNA Translation: ACJ64506.2
KT828539 Genomic DNA Translation: AMQ11134.1
KT828540 Genomic DNA Translation: AMQ11135.1
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

Similar proteinsi

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
FJ434338 mRNA Translation: ACJ64506.2
KT828539 Genomic DNA Translation: AMQ11134.1
KT828540 Genomic DNA Translation: AMQ11135.1
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

IntActiB7U540, 2 interactors

PTM databases

iPTMnetiB7U540
PhosphoSitePlusiB7U540

Proteomic databases

PRIDEiB7U540
ProteomicsDBi6260

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Genome annotation databases

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

Organism-specific databases

CTDi100134444
DisGeNETi100134444
EuPathDBiHostDB:ENSG00000260458.3
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
OMAiNNMEDKP
OrthoDBiEOG091G08HC
PhylomeDBiB7U540

Miscellaneous databases

GenomeRNAii100134444
PROiPR:B7U540
SOURCEiSearch...

Gene expression databases

BgeeiENSG00000260458 Expressed in 12 organ(s), highest expression level in skin of abdomen

Family and domain databases

Gene3Di2.60.40.1400, 1 hit
InterProiView protein in InterPro
IPR014756 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
PANTHERiPTHR11767 PTHR11767, 1 hit
PTHR11767:SF14 PTHR11767:SF14, 1 hit
PfamiView protein in Pfam
PF01007 IRK, 1 hit
PF08466 IRK_N, 1 hit
PRINTSiPR01325 KIR22CHANNEL
PR01320 KIRCHANNEL
SUPFAMiSSF81296 SSF81296, 1 hit
ProtoNetiSearch...

Entry informationi

Entry nameiKCJ18_HUMAN
AccessioniPrimary (citable) accession number: B7U540
Secondary accession number(s): A0A075B742, A0A142CKZ1, A0A142CKZ2
Entry historyiIntegrated into UniProtKB/Swiss-Prot: July 13, 2010
Last sequence update: October 14, 2015
Last modified: November 7, 2018
This is version 78 of the entry and version 3 of the sequence. See 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. SIMILARITY comments
    Index of protein domains and families
  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. Human chromosome 17
    Human chromosome 17: entries, gene names and cross-references to MIM
UniProt is an ELIXIR core data resource
Main funding by: National Institutes of Health

We'd like to inform you that we have updated our Privacy Notice to comply with Europe’s new General Data Protection Regulation (GDPR) that applies since 25 May 2018.

Do not show this banner again