Seroatlas · Human Serome Atlas

KRT4

Keratin, type II cytoskeletal 4

Also known as: CK4, CYK4, K2C4_HUMAN, K4

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

Protein identityUniProt · HPA

UniProt accession
P19013
Gene
KRT4
Ensembl
ENSG00000170477
Chromosome
12
Canonical length
520 aa
Protein class
Cancer-related genes, Disease related genes, Human disease related genes, Plasma proteins, Predicted intracellular proteins
Subcellular location
Intermediate filaments

OverviewNCBI Gene

The protein encoded by this gene is a member of the keratin gene family. The type II cytokeratins consist of basic or neutral proteins which are arranged in pairs of heterotypic keratin chains coexpressed during differentiation of simple and stratified epithelial tissues. This type II cytokeratin is specifically expressed in differentiated layers of the mucosal and esophageal epithelia with family member KRT13. Mutations in these genes have been associated with White Sponge Nevus, characterized by oral, esophageal, and anal leukoplakia. The type II cytokeratins are clustered in a region of chromosome 12q12-q13. [provided by RefSeq, Jul 2008]

Canonical amino-acid sequenceUniProt

520 residues, UniProt reviewed canonical sequence.

>P19013|KRT4
     1  MIARQQCVRG GPRGFSCGSA IVGGGKRGAF SSVSMSGGAG RCSSGGFGSR SLYNLRGNKS
    61  ISMSVAGSRQ GACFGGAGGF GTGGFGGGFG GSFSGKGGPG FPVCPAGGIQ EVTINQSLLT
   121  PLHVEIDPEI QKVRTEEREQ IKLLNNKFAS FIDKVQFLEQ QNKVLETKWN LLQQQTTTTS
   181  SKNLEPLFET YLSVLRKQLD TLGNDKGRLQ SELKTMQDSV EDFKTKYEEE INKRTAAEND
   241  FVVLKKDVDA AYLNKVELEA KVDSLNDEIN FLKVLYDAEL SQMQTHVSDT SVVLSMDNNR
   301  NLDLDSIIAE VRAQYEEIAQ RSKAEAEALY QTKVQQLQIS VDQHGDNLKN TKSEIAELNR
   361  MIQRLRAEIE NIKKQCQTLQ VSVADAEQRG ENALKDAHSK RVELEAALQQ AKEELARMLR
   421  EYQELMSVKL ALDIEIATYR KLLEGEEYRM SGECQSAVSI SVVSGSTSTG GISGGLGSGS
   481  GFGLSSGFGS GSGSGFGFGG SVSGSSSSKI ISTTTLNKRR

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against KRT4 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
0
Mean surface accessibility (rSASA)
0.58
Highest tissue expression
18,547 nTPM

Expression across tissuesHPA

Tissue

  • esophagus: 18,547 nTPM
  • salivary gland: 3,586 nTPM
  • vagina: 1,885 nTPM
  • tonsil: 1,330 nTPM
  • cervix: 1,325 nTPM
  • lung: 16 nTPM

Single-cell type

  • esophageal apical cells: 74,823 nCPM
  • esophageal suprabasal cells: 30,263 nCPM
  • suprabasal keratinocytes: 10,803 nCPM
  • esophageal basal cells: 1,078 nCPM
  • ocular epithelial cells: 652 nCPM
  • submucosal glandular cells: 360 nCPM

Immune cell

  • basophil: 0 nTPM
  • classical monocyte: 0 nTPM
  • eosinophil: 0 nTPM
  • gdT-cell: 0 nTPM
  • intermediate monocyte: 0 nTPM
  • MAIT T-cell: 0 nTPM

Brain region

  • amygdala: 0 nTPM
  • basal ganglia: 0 nTPM
  • cerebellum: 0 nTPM
  • cerebral cortex: 0 nTPM
  • choroid plexus: 0 nTPM
  • hippocampal formation: 0 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about KRT4.

Disease | AllUniProt

Conditions KRT4 is implicated in, by any mechanism.

Disease | GeneticClinVar

3 pathogenic / likely-pathogenic of 195 ClinVar records.

Conditions with pathogenic or likely-pathogenic variants.

  • White sponge nevus 1

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)
1.06
gnomAD pLI
0
gnomAD missense Z
-0.46
DepMap mean gene effect
-0.11
DepMap dependency class
selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 2% 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 KRT4 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 KRT4 as an antibody target. Whether an autoantibody or antibody against KRT4 could matter depends on whether native KRT4 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

KRT4 is annotated at the cell surface, where native KRT4 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 KRT4 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/KRT4. 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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