High impact information on MED6

• Furthermore, we find that Srb7p also binds Med6p and that this interaction is necessary for full transcriptional activation by different activators [1].
• These results suggest that distinct Mediator proteins in the Rgr1 subcomplex are required for activator-specific transcriptional activation and that the activation signals mediated by these Mediator proteins converge on Med6 (or the Srb4 subcomplex) to modulate Pol II activity [2].
• On the other hand, Med6 was required for all of these transcriptional activation processes [2].
• We report here that MED6 and SRB6, both of which encode essential components of the holoenzyme, are among the dominant suppressors and that the products of these genes interact physically with Srb4 [3].
• A flexible MED6 bridge and the MED7.MED21 hinge could account for changes in overall Mediator structure upon binding to Pol II or activators [4].

Biological context of MED6

• Four putative protein binding sites on the surface allow for assembly of the Mediator middle module and for binding of the conserved subunit MED6, which is shown to bridge to the Mediator head module [4].
• A single missense mutation in SRB4 can specifically suppress transcriptional defects caused by the med6 ts mutation, indicating a functional interaction between these two mediator subunits in the activation of transcription [5].

Physical interactions of MED6

• In the yeast Saccharomyces cerevisiae, Med21 is known to interact both with the Mediator subunit Med6 and the global co-repressor Tup1 [6].

References