{"entity":{"id":"fkbp12","kind":"target","name":"FKBP12 (FKBP1A)","aka":[],"tldr":"FKBP12 is the small protein that rapamycin-type drugs grab first; the drug-FKBP12 pair then clamps onto mTOR and switches off its growth signalling.","summary":"FK506-binding protein 1A (FKBP12) is a peptidyl-prolyl isomerase that acts as the intracellular receptor for rapamycin and its analogues. Everolimus and temsirolimus bind FKBP12, and the complex binds the FRB domain of mTOR, inhibiting mTORC1. The target is therefore listed for every rapalogue approved in kidney cancer, breast cancer, neuroendocrine tumours and tuberous sclerosis.","asOf":"2026-09-04","wikipedia":"https://en.wikipedia.org/wiki/FKBP1A","links":[{"label":"UniProt P62942: FKBP1A","url":"https://www.uniprot.org/uniprotkb/P62942/entry"},{"label":"HGNC:3711 FKBP1A","url":"https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/HGNC:3711"},{"label":"ChEMBL target CHEMBL1902","url":"https://www.ebi.ac.uk/chembl/explore/target/CHEMBL1902"}],"tags":[],"related":["mtor"],"cancers":["rcc","breast-hr-positive"],"sections":[],"technologies":[],"targets":[],"drugs":["everolimus","temsirolimus"],"companies":[],"institutions":[],"pathways":[],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"symbol":"FKBP1A","role":[],"sources":[],"specificity":"broadly-expressed","distribution":"few-types","specificityNote":"Broadly expressed or essential: HPA finds the RNA at low tissue specificity; the 2 medicines aimed at it (Everolimus, Temsirolimus) act on the wild-type protein, so normal tissue is exposed and the therapeutic window comes from the tumour's faster division or its dependence on the protein. HPA FKBP1A: RNA low tissue specificity; blood lineage group enriched (dendritic cells 676 nTPM, granulocytes 976 nTPM, monocytes 1,017 nTPM); no normal tissue stained high; highest cancer staining thyroid cancer (2 of 4 high). Distribution: 2 cancer families in the corpus carry a prevalence row, label threshold or catalogue link for it (Renal cell carcinoma, Breast cancer (all types)); Open Targets associates it with 7 specific cancer types at or above 0.5 (breast cancer, renal cell carcinoma, tuberous sclerosis, kidney angiomyolipoma, lymphangioleiomyomatosis, hamartoma and more). (Rule 7 of scripts/fetch-target-specificity.ts.)","specificitySources":[{"label":"Human Protein Atlas FKBP1A tissue","url":"https://www.proteinatlas.org/ENSG00000088832-FKBP1A/tissue","note":"RNA tissue and blood lineage specificity, normal tissue antibody staining (version 25.1, CC BY-SA 3.0)"},{"label":"Open Targets ENSG00000088832 associations","url":"https://platform.opentargets.org/target/ENSG00000088832/associations","note":"cancer associations at or above 0.5 (CC0)"}],"hgnc":"HGNC:3711","ensembl":"ENSG00000088832","uniprot":"P62942","entrez":"2280","firstDescribed":1989,"firstDescribedBasis":"sequence","firstDescribedNote":"Earliest sequence paper UniProt cites for the protein: Harding M.W. et al, Nature, 1989, \"A receptor for the immunosuppressant FK506 is a cis-trans peptidyl-prolyl isomerase\".","firstDescribedSource":"https://pubmed.ncbi.nlm.nih.gov/2477715/","biology":"An abundant cytosolic immunophilin that also regulates ryanodine and TGF-beta receptors; drug binding, not its own enzyme activity, is what matters for the mTOR effect.","whereFound":["Ubiquitous, cytosolic","Required for the action of everolimus, temsirolimus and sirolimus"],"targetClass":"other","prevalence":[{"cancerId":"metastatic-cancer","pct":"all","measure":"Housekeeping enzyme present in every dividing cell (rapamycin-binding protein); not a selection marker, which is why these drugs are given by cancer type rather than by test."}]},"route":"/targets/fkbp12/","neighbours":{"target":[{"id":"mtor","kind":"target","name":"mTOR","route":"/targets/mtor/"}],"cancer":[{"id":"breast-hr-positive","kind":"cancer","name":"HR-positive / HER2-negative breast cancer","route":"/cancers/breast-hr-positive/"},{"id":"rcc","kind":"cancer","name":"Renal cell carcinoma","route":"/cancers/rcc/"}],"drug":[{"id":"everolimus","kind":"drug","name":"Everolimus","route":"/drugs/everolimus/"},{"id":"temsirolimus","kind":"drug","name":"Temsirolimus","route":"/drugs/temsirolimus/"}]}}