MED1

Mediator of RNA polymerase II transcription subunit 1 also known as DRIP205 or Trap220 is a subunit of the Mediator complex and is a protein that in humans is encoded by the MED1 gene. MED1 functions as a nuclear receptor coactivator.

Function
The activation of gene transcription is a multistep process that is triggered by factors that recognize transcriptional enhancer sites in DNA. These factors work with co-activators to direct transcriptional initiation by the RNA polymerase II apparatus. The mediator of RNA polymerase II transcription subunit 1 protein is a subunit of the CRSP (cofactor required for SP1 activation) complex, which, along with TFIID, is required for efficient activation by SP1. This protein is also a component of other multisubunit complexes [e.g., thyroid hormone receptor-(TR-) associated proteins that interact with TR and facilitate TR function on DNA templates in conjunction with initiation factors and cofactors]. It also regulates p53-dependent apoptosis and it is essential for adipogenesis. This protein is known to have the ability to self-oligomerize.

Interactions
MED1 has been shown to interact with:


 * Androgen receptor,
 * Calcitriol receptor,
 * Cyclin-dependent kinase 8,
 * Estrogen receptor alpha,
 * Glucocorticoid receptor,
 * Hepatocyte nuclear factor 4 alpha,
 * P53,
 * PPARGC1A,
 * TGS1, and
 * Thyroid hormone receptor alpha.

Protein family
This entry represents subunit Med1 of the Mediator complex. The Med1 forms part of the Med9 submodule of the Srb/Med complex. It is one of three subunits essential for viability of the whole organism via its role in environmentally-directed cell-fate decisions.