Seroatlas · Human Serome Atlas

STK4

Serine/threonine-protein kinase 4

Also known as: KRS2, MST1, STK4_HUMAN, YSK3

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

Protein identityUniProt · HPA

UniProt accession
Q13043
Gene
STK4
Ensembl
ENSG00000101109
Chromosome
20
Canonical length
487 aa
Protein class
Disease related genes, Enzymes, Potential drug targets, Predicted intracellular proteins, RAS pathway related proteins
Subcellular location
Nucleoplasm,Nuclear bodies,Cytosol
Quaternary structure
Homodimer

OverviewNCBI Gene

The protein encoded by this gene is a cytoplasmic kinase that is structurally similar to the yeast Ste20p kinase, which acts upstream of the stress-induced mitogen-activated protein kinase cascade. The encoded protein can phosphorylate myelin basic protein and undergoes autophosphorylation. A caspase-cleaved fragment of the encoded protein has been shown to be capable of phosphorylating histone H2B. The particular phosphorylation catalyzed by this protein has been correlated with apoptosis, and it's possible that this protein induces the chromatin condensation observed in this process. [provided by RefSeq, Jul 2008]

Canonical amino-acid sequenceUniProt

487 residues, UniProt reviewed canonical sequence.

>Q13043|STK4
     1  METVQLRNPP RRQLKKLDED SLTKQPEEVF DVLEKLGEGS YGSVYKAIHK ETGQIVAIKQ
    61  VPVESDLQEI IKEISIMQQC DSPHVVKYYG SYFKNTDLWI VMEYCGAGSV SDIIRLRNKT
   121  LTEDEIATIL QSTLKGLEYL HFMRKIHRDI KAGNILLNTE GHAKLADFGV AGQLTDTMAK
   181  RNTVIGTPFW MAPEVIQEIG YNCVADIWSL GITAIEMAEG KPPYADIHPM RAIFMIPTNP
   241  PPTFRKPELW SDNFTDFVKQ CLVKSPEQRA TATQLLQHPF VRSAKGVSIL RDLINEAMDV
   301  KLKRQESQQR EVDQDDEENS EEDEMDSGTM VRAVGDEMGT VRVASTMTDG ANTMIEHDDT
   361  LPSQLGTMVI NAEDEEEEGT MKRRDETMQP AKPSFLEYFE QKEKENQINS FGKSVPGPLK
   421  NSSDWKIPQD GDYEFLKSWT VEDLQKRLLA LDPMMEQEIE EIRQKYQSKR QPILDAIEAK
   481  KRRQQNF

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against STK4 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
Intracellular
Secreted
No
Transmembrane segments
0
Mean surface accessibility (rSASA)
0.39
Highest tissue expression
46 nTPM

Expression across tissuesHPA

Tissue

  • bone marrow: 46 nTPM
  • lymph node: 37 nTPM
  • tonsil: 36 nTPM
  • thymus: 28 nTPM
  • appendix: 27 nTPM
  • spleen: 26 nTPM

Single-cell type

  • neutrophils: 1,741 nCPM
  • t-cells: 762 nCPM
  • cdc: 654 nCPM
  • neutrophil progenitors: 625 nCPM
  • nk-cells: 611 nCPM
  • b-cells: 579 nCPM

Immune cell

  • neutrophil: 69 nTPM
  • basophil: 41 nTPM
  • eosinophil: 35 nTPM
  • non-classical monocyte: 24 nTPM
  • gdT-cell: 22 nTPM
  • MAIT T-cell: 21 nTPM

Brain region

  • cerebral cortex: 15 nTPM
  • white matter: 15 nTPM
  • spinal cord: 14 nTPM
  • medulla oblongata: 14 nTPM
  • hypothalamus: 14 nTPM
  • thalamus: 14 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about STK4.

Disease | AllUniProt

Conditions STK4 is implicated in, by any mechanism.

  • Immunodeficiency 110 with lymphoproliferation (IMD110) MIM:614868

Disease | GeneticClinVar

19 pathogenic / likely-pathogenic of 311 ClinVar records.

Conditions with pathogenic or likely-pathogenic variants.

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)
0.52
gnomAD pLI
0.01
gnomAD missense Z
1.47
DepMap mean gene effect
-0.1
DepMap dependency class
selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 10% 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 STK4 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 STK4 as an antibody target. Whether an autoantibody or antibody against STK4 could matter depends on whether native STK4 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

STK4 is annotated as predominantly intracellular. Intracellular proteins are common autoantibody markers, becoming visible to the immune system after cell injury or altered processing, but are usually markers of disease rather than direct drivers.

Annotation status

The present source text does not explicitly label STK4 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/STK4. 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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