Seroatlas · Human Serome Atlas

KCNJ9

G protein-activated inward rectifier potassium channel 3

Also known as: GIRK3, KCNJ9_HUMAN, Kir3.3

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

Protein identityUniProt · HPA

UniProt accession: Q92806
Gene: KCNJ9
Ensembl: ENSG00000162728
Chromosome: 1
Canonical length: 393 aa
Protein class: Predicted membrane proteins, Transporters, Voltage-gated ion channels

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, is controlled by G-proteins. It associates with another G-protein-activated potassium channel to form a heteromultimeric pore-forming complex. [provided by RefSeq, Jul 2008]

Canonical amino-acid sequenceUniProt

393 residues, UniProt reviewed canonical sequence.

>Q92806|KCNJ9
     1  MAQENAAFSP GQEEPPRRRG RQRYVEKDGR CNVQQGNVRE TYRYLTDLFT TLVDLQWRLS
    61  LLFFVLAYAL TWLFFGAIWW LIAYGRGDLE HLEDTAWTPC VNNLNGFVAA FLFSIETETT
   121  IGYGHRVITD QCPEGIVLLL LQAILGSMVN AFMVGCMFVK ISQPNKRAAT LVFSSHAVVS
   181  LRDGRLCLMF RVGDLRSSHI VEASIRAKLI RSRQTLEGEF IPLHQTDLSV GFDTGDDRLF
   241  LVSPLVISHE IDAASPFWEA SRRALERDDF EIVVILEGMV EATGMTCQAR SSYLVDEVLW
   301  GHRFTSVLTL EDGFYEVDYA SFHETFEVPT PSCSARELAE AAARLDAHLY WSIPSRLDEK
   361  VEEEGAGEGA GGEAGADKEQ NGCLPPPESE SKV

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against KCNJ9 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): 0.38
Highest tissue expression: 69 nTPM

Expression across tissuesHPA

Tissue

cerebellum: 69 nTPM
cerebral cortex: 59 nTPM
midbrain: 45 nTPM
hippocampal formation: 42 nTPM
amygdala: 35 nTPM
basal ganglia: 35 nTPM

Single-cell type

brain excitatory neurons: 22 nCPM
brain inhibitory neurons: 14 nCPM
retinal amacrine cells: 13 nCPM
adrenal medulla cells: 11 nCPM
oligodendrocytes: 9.8 nCPM
retinal bipolar cells: 9.8 nCPM

Immune cell

MAIT T-cell: 0.1 nTPM
memory CD8 T-cell: 0.1 nTPM
basophil: 0 nTPM
classical monocyte: 0 nTPM
eosinophil: 0 nTPM
gdT-cell: 0 nTPM

Brain region

cerebellum: 98 nTPM
white matter: 89 nTPM
thalamus: 86 nTPM
cerebral cortex: 86 nTPM
amygdala: 79 nTPM
basal ganglia: 68 nTPM

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: 0.3
gnomAD missense Z: 4.22
DepMap mean gene effect: -0.28
DepMap dependency class: selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 5% 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 KCNJ9 as an antibody target. Whether an autoantibody or antibody against KCNJ9 could matter depends on whether native KCNJ9 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

KCNJ9 is annotated at the cell surface, where native KCNJ9 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 KCNJ9 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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