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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

  1. inward rectifier potassium channel activity Source: UniProtKB

GO - Biological processi

  1. potassium ion transmembrane transport Source: GOC
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
ProteomesiUP000005640: Unplaced

Organism-specific databases

HGNCiHGNC:39080. KCNJ18.

Subcellular locationi

Topology

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Topological domaini1 – 8484CytoplasmicSequence AnalysisAdd
BLAST
Transmembranei85 – 10521HelicalSequence AnalysisAdd
BLAST
Topological domaini106 – 15651ExtracellularSequence AnalysisAdd
BLAST
Transmembranei157 – 17721HelicalSequence AnalysisAdd
BLAST
Topological domaini178 – 433256CytoplasmicSequence AnalysisAdd
BLAST

GO - Cellular componenti

  1. integral component of membrane Source: UniProtKB-KW
  2. plasma membrane Source: UniProtKB
Complete GO annotation...

Keywords - Cellular componenti

Cell membrane, Membrane

Pathology & Biotechi

Involvement in diseasei

Thyrotoxic periodic paralysis 21 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)LengthDescriptionGraphical viewFeature identifierActions
Natural varianti140 – 1401T → M in TTPP2. 1 Publication
VAR_063286
Natural varianti205 – 2051R → H in TTPP2; hypermorphic; longer time required for half-maximal current degradation. 1 Publication
VAR_063287
Natural varianti354 – 3541T → M in TTPP2; small decrease in current density. 1 Publication
VAR_063288
Natural varianti366 – 3661K → R in TTPP2; hypermorphic; longer time required for half-maximal current degradation. 1 Publication
VAR_063289

Mutagenesis

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Mutagenesisi354 – 3541T → E: Decreases the single-channel open probability (Po) without altering its conductance. 1 Publication

Keywords - Diseasei

Disease mutation

Organism-specific databases

MIMi613239. phenotype.
Orphaneti79102. Thyrotoxic periodic paralysis.

PTM / Processingi

Molecule processing

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Chaini1 – 433433Inward rectifier potassium channel 18PRO_0000395171Add
BLAST

Amino acid modifications

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Modified residuei75 – 751S-nitrosocysteineBy similarity

Post-translational modificationi

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

Keywords - PTMi

Phosphoprotein, S-nitrosylation

Proteomic databases

PRIDEiB7U540.

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

BioGridi936647. 1 interaction.

Structurei

3D structure databases

ProteinModelPortaliB7U540.
SMRiB7U540. Positions 42-372.
ModBaseiSearch...
MobiDBiSearch...

Family & Domainsi

Sequence similaritiesi

Keywords - Domaini

Transmembrane, Transmembrane helix

Phylogenomic databases

HOVERGENiHBG006178.
InParanoidiB7U540.
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]
PIRSFiPIRSF005465. GIRK_kir. 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
MTAASQANPY SIVSLEEDGL HLVTMSGAKG FGNGKVHTQH 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 AHTLLFSHNA
210 220 230 240 250
VVALRDGKLC LMWRVGNLRK SHIVEAHVRA QLIKPRVTEE GEYIPLDQVD
260 270 280 290 300
IDVGFDKGLD RIFLVSPITI LHEIDEASPL LGISRQDLET DDFEIVVILE
310 320 330 340 350
GMVEATAMTT QARSSYLANE ILWGHRFEPV LFEEKNQFKI DHSHFHKTYE
360 370 380 390 400
VPSTPRCSAK DLVENKFLLP SANSFCYENE LAFLSRDEED EADGDQDGRS
410 420 430
RDGLSPQARH DFDRLQAGGG VLEQRPYRRG SEI
Length:433
Mass (Da):48,738
Last modified:December 15, 2009 - v2
Checksum:i04FC98656CD046D1
GO

Natural variant

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Natural varianti140 – 1401T → M in TTPP2. 1 Publication
VAR_063286
Natural varianti205 – 2051R → H in TTPP2; hypermorphic; longer time required for half-maximal current degradation. 1 Publication
VAR_063287
Natural varianti354 – 3541T → M in TTPP2; small decrease in current density. 1 Publication
VAR_063288
Natural varianti366 – 3661K → R in TTPP2; hypermorphic; longer time required for half-maximal current degradation. 1 Publication
VAR_063289

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
FJ434338 mRNA. Translation: ACJ64506.2.
UniGeneiHs.200629.

Keywords - Coding sequence diversityi

Polymorphism

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
FJ434338 mRNA. Translation: ACJ64506.2.
UniGeneiHs.200629.

3D structure databases

ProteinModelPortaliB7U540.
SMRiB7U540. Positions 42-372.
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

BioGridi936647. 1 interaction.

Proteomic databases

PRIDEiB7U540.

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Organism-specific databases

GeneCardsiGC17P8V0344.
HGNCiHGNC:39080. KCNJ18.
HPAiHPA027021.
MIMi613236. gene.
613239. phenotype.
neXtProtiNX_B7U540.
Orphaneti79102. Thyrotoxic periodic paralysis.
GenAtlasiSearch...

Phylogenomic databases

HOVERGENiHBG006178.
InParanoidiB7U540.
PhylomeDBiB7U540.

Miscellaneous databases

NextBioi33696320.
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]
PIRSFiPIRSF005465. GIRK_kir. 1 hit.
PRINTSiPR01325. KIR22CHANNEL.
PR01320. KIRCHANNEL.
SUPFAMiSSF81296. SSF81296. 1 hit.
ProtoNetiSearch...

Publicationsi

  1. Cited for: NUCLEOTIDE SEQUENCE [MRNA], FUNCTION, INDUCTION BY TRIIODOTHYRONINE, TISSUE SPECIFICITY, PHOSPHORYLATION, VARIANTS TTPP2 MET-140; HIS-205; MET-354 AND ARG-366, CHARACTERIZATION OF VARIANTS TTPP2 HIS-205; MET-354 AND ARG-366, MUTAGENESIS OF THR-354.
    Tissue: Brain.

Entry informationi

Entry nameiKCJ18_HUMAN
AccessioniPrimary (citable) accession number: B7U540
Entry historyi
Integrated into UniProtKB/Swiss-Prot: July 13, 2010
Last sequence update: December 15, 2009
Last modified: March 4, 2015
This is version 48 of the entry and version 2 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

External Data

Dasty 3

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 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.