Med complex

Transcriptional regulation and mediator

As a central integrator of both general and Transcription Factors (TFs)-specific regulatory signals, the Mediator complex plays a prominent role in controlling transcription on a genome-wide scale. Mediator is very large, comprising 25 subunits in yeast, with a total molecular weight of one mega-Dalton. Mediator is organized into four distinct modules named Head, Middle, Tail and a separable Kinase module (CKM). Mediators in higher eukaryotes are larger than they are in yeast, with 30 or more subunits making up the human version. One feature of the mammalian Mediator is that its subunit composition is variable, raising the possibility that there are several versions, each one responding to a different, although possibly overlapping set of activators.
Our group study at the molecular level how human transcription factors exert their action. Our main project is to characterize at the structural level the Mediator complex, with a specific focus on subunits from the tail module, which mainly binds TFs, starting from MED23, and to understand how transcription factors bound to individual subunits transmit regulatory information to the whole complex. To do this, we are employing a variety of biochemical, biophysical, and chemical biology techniques.