Mediator complex subunit 21 (MED21)

Mediator complex subunit 21 (MED21) is a highly conserved protein that is a core component of the Mediator complex, an essential transcriptional coactivator necessary for regulated transcription of nearly all RNA polymerase II-dependent genes. MED21 directly interacts with the RNA polymerase II holoenzyme and, in conjunction with MED7, forms a structural hinge within the Mediator's middle module. This hinge allows the complex to undergo conformational changes crucial for its function as a flexible interface between gene-specific regulatory proteins and the basal transcription machinery. MED21 thereby facilitates assembly of the preinitiation complex, enabling the integration of various signaling pathways that control gene expression. Functional studies highlight MED21's importance in processes such as cellular proliferation, differentiation, and in plants, immune responses against pathogens[1][2][3][4][5][7][8][10].\n\nMED21 is encoded by the MED21 gene, with alternative splicing producing multiple isoforms. While vital for basic transcriptional machinery, there are currently no drugs specifically targeting MED21, and it is not considered a therapeutic target such as a receptor or enzyme. However, disruptions in Mediator complex function, including MED21, have been linked to certain cancers and other diseases[7].

Other names

SRB7SURB7hSrb7Mediator of RNA polymerase II transcription subunit 21RNAPII complex component SRB7RNA polymerase II holoenzyme component SRB7suppressor of RNA polymerase B homolog