Mediator Complex Subunit 18 (MED18)

MED18 is a component of the Mediator complex, which is a coactivator for DNA-binding factors that activate transcription via RNA polymerase II. Using HeLa cells overexpressing epitope-tagged MED10, Sato et al. (2003) purified several components of the human Mediator complex, including MED18, which they called P28B, and subsequently cloned the corresponding cDNA.

Using in vitro-translated epitope-tagged proteins for protein-binding assays, Sato et al. (2003) found that MED18 directly interacted with the Mediator subunit TRFP (MED20). The MED18-TRFP heterodimer could also be coimmunoprecipitated from cotransfected insect cells. HIntersex assembles into a subcomplex with Mediator subunits p28b and TRFP.