Seroatlas · Human Serome Atlas

KCNJ2

Inward rectifier potassium channel 2

Also known as: IRK1, KCNJ2_HUMAN, Kir2.1, LQT7

Cross-references: UniProt · Ensembl · Human Protein Atlas · GeneCards · NCBI Gene

Protein identityUniProt · HPA

UniProt accession: P63252
Gene: KCNJ2
Ensembl: ENSG00000123700
Chromosome: 17
Canonical length: 427 aa
Protein class: Disease related genes, FDA approved drug targets, Human disease related genes, Predicted membrane proteins, Transporters, Voltage-gated ion channels
Quaternary structure: Homotetramer

OverviewNCBI Gene

Potassium channels are present in most mammalian cells, where they participate in a wide range of physiologic responses. The protein encoded by this gene is an integral membrane protein and inward-rectifier type potassium channel. The encoded protein, which has a greater tendency to allow potassium to flow into a cell rather than out of a cell, probably participates in establishing action potential waveform and excitability of neuronal and muscle tissues. Mutations in this gene have been associated with Andersen syndrome, which is characterized by periodic paralysis, cardiac arrhythmias, and dysmorphic features. [provided by RefSeq, Jul 2008]

Canonical amino-acid sequenceUniProt

427 residues, UniProt reviewed canonical sequence.

>P63252|KCNJ2
     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

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against KCNJ2 can act on the native protein depends on physical access: surface and secreted proteins are reachable by circulating antibodies, intracellular proteins usually are not.

Antibody reachability: Cell surface
Secreted: No
Transmembrane segments: 2
Mean surface accessibility (rSASA): 0.39
Highest tissue expression: 34 nTPM

Expression across tissuesHPA

Tissue

parathyroid gland: 34 nTPM
heart muscle: 9.2 nTPM
skeletal muscle: 9.1 nTPM
tongue: 7.8 nTPM
retina: 7.1 nTPM
spleen: 6.9 nTPM

Single-cell type

neutrophils: 313 nCPM
oligodendrocytes: 159 nCPM
retinal horizontal cells: 152 nCPM
cardiomyocytes: 107 nCPM
kupffer cells: 92 nCPM
myonuclei: 74 nCPM

Immune cell

neutrophil: 31 nTPM
non-classical monocyte: 7.3 nTPM
intermediate monocyte: 6.9 nTPM
eosinophil: 5.6 nTPM
basophil: 4.2 nTPM
classical monocyte: 3.5 nTPM

Brain region

white matter: 95 nTPM
basal ganglia: 48 nTPM
medulla oblongata: 48 nTPM
pons: 47 nTPM
midbrain: 42 nTPM
thalamus: 39 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about KCNJ2.

Disease | AllUniProt

Conditions KCNJ2 is implicated in, by any mechanism.

Long QT syndrome 7 (LQT7) MIM:170390
Short QT syndrome 3 (SQT3) MIM:609622
Atrial fibrillation, familial, 9 (ATFB9) MIM:613980

Disease | GeneticClinVar

65 pathogenic / likely-pathogenic of 680 ClinVar records.

Conditions with pathogenic or likely-pathogenic variants.

Andersen Tawil syndrome
Short QT syndrome type 3
Congenital long QT syndrome
Cardiovascular phenotype
Atrial fibrillation, familial, 9

Genetic constraint and essentialitygnomAD · DepMap

Does the body need this protein intact? Low LOEUF or a strong DepMap dependency means loss or blockade of the protein is likely to be felt.

gnomAD LOEUF (loss-of-function intolerance): 0.62
gnomAD pLI: 0.31
gnomAD missense Z: 2.75
DepMap mean gene effect: -0.01
DepMap dependency class: none

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 4% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

Molecular functions

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads KCNJ2 as an antibody target. Whether an autoantibody or antibody against KCNJ2 could matter depends on whether native KCNJ2 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

KCNJ2 is annotated at the cell surface, where native KCNJ2 is exposed to circulating antibodies and is a prime autoantibody target that could block, deplete, or overstimulate it.

Annotation status

The present source text does not explicitly label KCNJ2 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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