Seroatlas · Human Serome Atlas

MAPK9

Mitogen-activated protein kinase 9

Also known as: JNK2, MK09_HUMAN, p54a, PRKM9, SAPK

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

Protein identityUniProt · HPA

UniProt accession
P45984
Gene
MAPK9
Ensembl
ENSG00000050748
Chromosome
5
Canonical length
424 aa
Protein class
Enzymes, Predicted intracellular proteins, RAS pathway related proteins
Subcellular location
Nuclear speckles,Plasma membrane,Cytosol

OverviewNCBI Gene

The protein encoded by this gene is a member of the MAP kinase family. MAP kinases act as an integration point for multiple biochemical signals, and are involved in a wide variety of cellular processes such as proliferation, differentiation, transcription regulation and development. This kinase targets specific transcription factors, and thus mediates immediate-early gene expression in response to various cell stimuli. It is most closely related to MAPK8, both of which are involved in UV radiation induced apoptosis, thought to be related to the cytochrome c-mediated cell death pathway. This gene and MAPK8 are also known as c-Jun N-terminal kinases. This kinase blocks the ubiquitination of tumor suppressor p53, and thus it increases the stability of p53 in nonstressed cells. Studies of this gene's mouse counterpart suggest a key role in T-cell differentiation. Several alternatively spliced transcript variants encoding distinct isoforms have been reported. [provided by RefSeq, Sep 2008]

Canonical amino-acid sequenceUniProt

424 residues, UniProt reviewed canonical sequence.

>P45984|MAPK9
     1  MSDSKCDSQF YSVQVADSTF TVLKRYQQLK PIGSGAQGIV CAAFDTVLGI NVAVKKLSRP
    61  FQNQTHAKRA YRELVLLKCV NHKNIISLLN VFTPQKTLEE FQDVYLVMEL MDANLCQVIH
   121  MELDHERMSY LLYQMLCGIK HLHSAGIIHR DLKPSNIVVK SDCTLKILDF GLARTACTNF
   181  MMTPYVVTRY YRAPEVILGM GYKENVDIWS VGCIMGELVK GCVIFQGTDH IDQWNKVIEQ
   241  LGTPSAEFMK KLQPTVRNYV ENRPKYPGIK FEELFPDWIF PSESERDKIK TSQARDLLSK
   301  MLVIDPDKRI SVDEALRHPY ITVWYDPAEA EAPPPQIYDA QLEEREHAIE EWKELIYKEV
   361  MDWEERSKNG VVKDQPSDAA VSSNATPSQS SSINDISSMS TEQTLASDTD SSLDASTGPL
   421  EGCR

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against MAPK9 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)
0.31
Highest tissue expression
69 nTPM

Expression across tissuesHPA

Tissue

  • cerebellum: 69 nTPM
  • cerebral cortex: 58 nTPM
  • pancreas: 43 nTPM
  • skeletal muscle: 38 nTPM
  • hypothalamus: 34 nTPM
  • tongue: 33 nTPM

Single-cell type

  • brain excitatory neurons: 88 nCPM
  • retinal ganglion cells: 81 nCPM
  • thyrotrophs: 78 nCPM
  • brain inhibitory neurons: 77 nCPM
  • other brain neurons: 75 nCPM
  • sertoli cells: 74 nCPM

Immune cell

  • basophil: 16 nTPM
  • T-reg: 2.7 nTPM
  • eosinophil: 2.3 nTPM
  • non-classical monocyte: 2.3 nTPM
  • gdT-cell: 1.6 nTPM
  • MAIT T-cell: 1.6 nTPM

Brain region

  • cerebral cortex: 98 nTPM
  • cerebellum: 90 nTPM
  • basal ganglia: 75 nTPM
  • white matter: 75 nTPM
  • pons: 70 nTPM
  • hypothalamus: 70 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)
0.52
gnomAD pLI
0.07
gnomAD missense Z
2.28
DepMap mean gene effect
0.16
DepMap dependency class
none

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 6% 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 MAPK9 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 MAPK9 as an antibody target. Whether an autoantibody or antibody against MAPK9 could matter depends on whether native MAPK9 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

MAPK9 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 MAPK9 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/MAPK9. 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).

© 2026 · Seroatlas, Discover Oregon LLC · Terms of use

Loading the interactive Seroatlas protein explorer...