MED17 (E3V6Y) Rabbit mAb #64733

The mammalian Mediator complex is a multi-subunit protein complex that acts to relay signals from transcription factors to RNA polymerase II (Pol II) and the basal transcription machinery. In other words, Mediator acts as a centralized hub or integrator for transcriptional regulation (reviewed in 1,2). Multiple studies have shown that Mediator functions include epigenetic regulation, transcriptional elongation, transcription termination, mRNA processing, non-coding RNA activation, and super-enhancer formation. Through these functions, Mediator contributes to the regulation of many biological processes, including insulin signaling (3), NF-κB-dependent signaling (4), stem cell pluripotency and self-renewal (5,6), and proliferation of colon cancer cells (7,8). The Mediator complex consists of 31 protein subunits and can be divided into four distinct modules: the head, middle, tail, and CDK8 kinase module. The CDK8 kinase module contains the CDK8, cyclin C, MED12, and MED13 subunits and is thought to act as a molecular switch, phosphorylating the C-terminal domain (CTD) of Rpb1, the large subunit of Pol II, to inhibit Pol II recruitment and transcription initiation (9,10).

MED17, along with MED6, 8, 11, 18, 20, and 22, make up the head module of the Mediator complex (11). MED17 is critical for head module assembly as it acts as a scaffold to recruit MED11 and MED22 (12). Phosphorylation of MED17 has been shown as a regulatory mechanism in lipogenesis and NF-κB signaling (13,14).