Seroatlas · Human Serome Atlas

SLC9A4

Sodium/hydrogen exchanger 4

Also known as: NHE4, SL9A4_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
Q6AI14
Gene
SLC9A4
Ensembl
ENSG00000180251
Chromosome
2
Canonical length
798 aa
Protein class
Metabolic proteins, Predicted membrane proteins, Transporters
Subcellular location
Nucleoplasm,Plasma membrane
Quaternary structure
Homodimer

OverviewNCBI Gene

Predicted to enable potassium:proton antiporter activity and sodium:proton antiporter activity. Predicted to be involved in monoatomic cation transmembrane transport; regulation of intracellular pH; and transepithelial ammonium transport. Predicted to act upstream of or within gastric acid secretion and glandular epithelial cell development. Predicted to be located in basolateral plasma membrane. Predicted to be active in plasma membrane. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

798 residues, UniProt reviewed canonical sequence.

>Q6AI14|SLC9A4
     1  MALQMFVTYS PWNCLLLLVA LECSEASSDL NESANSTAQY ASNAWFAAAS SEPEEGISVF
    61  ELDYDYVQIP YEVTLWILLA SLAKIGFHLY HRLPGLMPES CLLILVGALV GGIIFGTDHK
   121  SPPVMDSSIY FLYLLPPIVL EGGYFMPTRP FFENIGSILW WAVLGALINA LGIGLSLYLI
   181  CQVKAFGLGD VNLLQNLLFG SLISAVDPVA VLAVFEEARV NEQLYMMIFG EALLNDGITV
   241  VLYNMLIAFT KMHKFEDIET VDILAGCARF IVVGLGGVLF GIVFGFISAF ITRFTQNISA
   301  IEPLIVFMFS YLSYLAAETL YLSGILAITA CAVTMKKYVE ENVSQTSYTT IKYFMKMLSS
   361  VSETLIFIFM GVSTVGKNHE WNWAFICFTL AFCQIWRAIS VFALFYISNQ FRTFPFSIKD
   421  QCIIFYSGVR GAGSFSLAFL LPLSLFPRKK MFVTATLVVI YFTVFIQGIT VGPLVRYLDV
   481  KKTNKKESIN EELHIRLMDH LKAGIEDVCG HWSHYQVRDK FKKFDHRYLR KILIRKNLPK
   541  SSIVSLYKKL EMKQAIEMVE TGILSSTAFS IPHQAQRIQG IKRLSPEDVE SIRDILTSNM
   601  YQVRQRTLSY NKYNLKPQTS EKQAKEILIR RQNTLRESMR KGHSLPWGKP AGTKNIRYLS
   661  YPYGNPQSAG RDTRAAGFSD DDSSDPGSPS ITFSACSRIG SLQKQEAQEI IPMKSLHRGR
   721  KAFSFGYQRN TSQEEYLGGV RRVALRPKPL FHAVDEEGES GGESEGKASL VEVRSRWTAD
   781  HGHGRDHHRS HSPLLQKK

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against SLC9A4 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
10
Mean surface accessibility (rSASA)
0.42
Highest tissue expression
51 nTPM

Expression across tissuesHPA

Tissue

  • stomach: 51 nTPM
  • kidney: 8 nTPM
  • duodenum: 1.8 nTPM
  • esophagus: 1.4 nTPM
  • salivary gland: 1.3 nTPM
  • skeletal muscle: 1.2 nTPM

Single-cell type

  • mucous neck cells: 170 nCPM
  • gastric chief cells: 134 nCPM
  • parietal cells: 99 nCPM
  • renal connecting tubule cells: 94 nCPM
  • renal collecting duct principal cells: 67 nCPM
  • foveolar cells: 58 nCPM

Immune cell

  • neutrophil: 0.1 nTPM
  • basophil: 0 nTPM
  • classical monocyte: 0 nTPM
  • eosinophil: 0 nTPM
  • gdT-cell: 0 nTPM
  • intermediate monocyte: 0 nTPM

Brain region

  • cerebellum: 3.8 nTPM
  • cerebral cortex: 3.4 nTPM
  • basal ganglia: 3.1 nTPM
  • hippocampal formation: 3 nTPM
  • hypothalamus: 3 nTPM
  • white matter: 3 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)
1.1
gnomAD pLI
0
gnomAD missense Z
-0.61
DepMap mean gene effect
-0.05
DepMap dependency class
selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 3% 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

InteractionsUniProt · HPA

Protein binding partners of SLC9A4 in the human serome: UniProt-annotated complex subunits plus reported interactors. Each links to its own Seroatlas record.

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads SLC9A4 as an antibody target. Whether an autoantibody or antibody against SLC9A4 could matter depends on whether native SLC9A4 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

SLC9A4 is annotated at the cell surface, where native SLC9A4 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 SLC9A4 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/SLC9A4. Study-independent annotations aggregated from UniProt, Human Protein Atlas, PubMed, IEDB, Pfam, InterPro, Gene Ontology, AlphaFold, gnomAD, DepMap, ClinVar, TCGA. Catalog release seroatlas-reviewed-human-uniprot-20260313.

Seroatlas is the reference for exploring autoantibody and antibody serology at the human-protein level: the autoreactome and human serome, multiplex serology (HuProt, HuScan, VirScan, PhIP-Seq).

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