{"term":{"id":"13049","title":"coreceptor","longtitle":"IUPAC Gold Book - coreceptor","doi":"10.1351\/goldbook.13049","code":"13049","status":"current","definitions":[{"id":1,"text":"Cell surface protein receptor that recognizes a substance bound to a primary receptor, and binds to a signaling molecule that thereby enhances the activity of another receptor.","notes":{"1":"Optimal T cell activation in an immune response depends on the involvement of relevant coreceptors occurring in a cluster with the T-cell receptors (TCRs). The coreceptors are CD4 or CD8 proteins, which lie alongside the T-cell receptor in the plasma membrane. Only when both coreceptor and receptor bind the major histocompatibility complex (MHC) molecule-antigen complex simultaneously is the full set of intracellular effector molecules recruited and the signal pathway inside the cell maximally activated.","2":"B-cell receptors (BCRs) require the contributions of several coreceptors, notably CD19, CD21, and CD81 proteins, for full activation of intracellular signaling pathways."},"links":[{"term":"B-cell receptors (BCRs)","url":"https:\/\/goldbook.iupac.org\/terms\/view\/12936"},{"term":"CD4","url":"https:\/\/goldbook.iupac.org\/terms\/view\/12973"},{"term":"CD8","url":"https:\/\/goldbook.iupac.org\/terms\/view\/12976"},{"term":"T cell activation","url":"https:\/\/goldbook.iupac.org\/terms\/view\/13724"},{"term":"T-cell receptors (TCRs)","url":"https:\/\/goldbook.iupac.org\/terms\/view\/13714"},{"term":"major histocompatibility complex (MHC) molecule","url":"https:\/\/goldbook.iupac.org\/terms\/view\/13434"}],"sources":["PAC, 2012, 84, 1113. 'IUPAC glossary of terms used in immunotoxicology (IUPAC Recommendations 2012)' on page 1150 (https:\/\/doi.org\/10.1351\/PAC-REC-11-06-03)"]}],"altoutputs":{"html":"https:\/\/goldbook.iupac.org\/terms\/view\/13049\/html","xml":"https:\/\/goldbook.iupac.org\/terms\/view\/13049\/xml","plain":"https:\/\/goldbook.iupac.org\/terms\/view\/13049\/plain"},"citation":"Citation: 'coreceptor' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351\/goldbook.13049","license":"The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0\/) for individual terms.","collection":"If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org .","disclaimer":"The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using.","accessed":"2026-05-14T00:00:50+00:00"}}