{"entity":{"id":"mapk3","kind":"target","name":"MAPK3","aka":["mitogen-activated protein kinase 3","Mitogen-activated protein kinase 3","ERK1","p44mapk","p44erk1","ERK-1","PRKM3"],"tldr":"MAPK3 (Mitogen-activated protein kinase 3) is a protein kinase, an enzyme that switches other proteins on by adding phosphate groups. The public catalogues list it as a drug target, and clinical evidence ties its variants to diagnosis, prognosis or drug response.","summary":"Serine/threonine kinase which acts as an essential component of the MAP kinase signal transduction pathway. MAPK1/ERK2 and MAPK3/ERK1 are the 2 MAPKs which play an important role in the MAPK/ERK cascade. They participate also in a signalling cascade initiated by activated KIT and KITLG/SCF.\n\nOpen Targets scores its association with cancer at 0.63 (direct and indirect evidence; datatypes literature 0.99, affected pathway 0.97, genetic association 0.00, clinical 0.19).","asOf":"2026-09-23","links":[{"label":"HGNC HGNC:6877","url":"https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/HGNC:6877"},{"label":"UniProt P27361","url":"https://www.uniprot.org/uniprotkb/P27361/entry"},{"label":"NCBI Gene 5595","url":"https://www.ncbi.nlm.nih.gov/gene/5595"},{"label":"Ensembl ENSG00000102882","url":"https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000102882"}],"tags":["cancer-genes-wave"],"related":["open-targets"],"cancers":[],"sections":[],"technologies":[],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":["ras-mapk"],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":["Written by scripts/fetch-cancer-genes.ts from CIViC, Open Targets, IntOGen, HGNC and UniProt; the function text is UniProt's, condensed and in UK spelling. Roles: Open Targets known-drug datatype score 0.19. Evidence tier \"clinical-evidence\" is the strongest of those signals.","Prevalence not recorded: none of the sources gives a positivity rate."],"provenance":{"editedBy":"scripts/fetch-cancer-genes.ts (CIViC, Open Targets, IntOGen, HGNC, UniProt)","editedOn":"2026-09-23"},"symbol":"MAPK3","role":["drug-target"],"evidenceTier":"clinical-evidence","sources":[{"label":"HGNC HGNC:6877","url":"https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/HGNC:6877","note":"approved symbol, name, aliases, locus and cross-references (hgnc_complete_set.txt)"},{"label":"UniProt P27361","url":"https://www.uniprot.org/uniprotkb/P27361/entry","note":"protein name, function text, keywords and locations (REST API)"},{"label":"Open Targets ENSG00000102882","url":"https://platform.opentargets.org/target/ENSG00000102882/associations","note":"association with cancer (MONDO_0004992) 0.63;  (GraphQL API, CC0)"}],"specificity":"broadly-expressed","distribution":"not-established","specificityNote":"Broadly expressed or essential: HPA finds the RNA at low tissue specificity; a medicine acting on the wild-type protein would expose normal tissue too. HPA MAPK3: RNA low tissue specificity; blood lineage lineage enriched (granulocytes 49 nTPM); high antibody staining in 12 normal tissues; highest cancer staining colorectal cancer (12 of 12 high). Distribution: no corpus cancer carries a prevalence row, threshold or catalogue link for it; Open Targets associates it with 0 specific cancer types at or above 0.5. (Rule 7 of scripts/fetch-target-specificity.ts.)","specificitySources":[{"label":"Human Protein Atlas MAPK3 tissue","url":"https://www.proteinatlas.org/ENSG00000102882-MAPK3/tissue","note":"RNA tissue and blood lineage specificity, normal tissue antibody staining (version 25.1, CC BY-SA 3.0)"},{"label":"Open Targets ENSG00000102882 associations","url":"https://platform.opentargets.org/target/ENSG00000102882/associations","note":"cancer associations at or above 0.5 (CC0)"}],"hgnc":"HGNC:6877","ensembl":"ENSG00000102882","uniprot":"P27361","entrez":"5595","firstDescribed":1992,"firstDescribedBasis":"sequence","firstDescribedNote":"Earliest sequence paper UniProt cites for the protein: Owaki et al, Biochem. Biophys. Res. Commun, 1992, \"Extracellular signal-regulated kinases in T cells: characterization of human ERK1 and ERK2 cDNAs\".","firstDescribedSource":"https://pubmed.ncbi.nlm.nih.gov/1540184/","biology":"Serine/threonine kinase which acts as an essential component of the MAP kinase signal transduction pathway. MAPK1/ERK2 and MAPK3/ERK1 are the 2 MAPKs which play an important role in the MAPK/ERK cascade. They participate also in a signalling cascade initiated by activated KIT and KITLG/SCF. Depending on the cellular context, the MAPK/ERK cascade mediates diverse biological functions such as cell growth, adhesion, survival and differentiation through the regulation of transcription, translation, cytoskeletal rearrangements. The MAPK/ERK cascade also plays a role in initiation and regulation of meiosis, mitosis, and postmitotic functions in differentiated cells by phosphorylating a number of transcription factors. About 160 substrates have already been discovered for ERKs. Location: Cytoplasm; Nucleus; Membrane, caveola; Cell junction, focal adhesion (UniProt). Locus 16p11.2 (HGNC).","whereFound":[],"targetClass":"kinase","prevalence":[]},"route":"/targets/mapk3/","neighbours":{"collection":[{"id":"open-targets","kind":"collection","name":"Open Targets Platform","route":"/collections/open-targets/"}],"pathway":[{"id":"ras-mapk","kind":"pathway","name":"RAS / RAF / MEK / ERK (MAPK)","route":"/pathways/ras-mapk/"}]}}