Mediator Complex Subunit 2 (MED2)

MED2 belongs to the mediator complex subunit 2 family. The yeast Mediator complex is required for transcriptional regulation both in vivo and in vitro, and its function is conserved in all eukaryotes. Mediator interacts with both transcriptional activators and RNA polymerase II, but little is known about the mechanisms by which it operates at the molecular level. The cyclin-dependent kinase Srb10 interacts with, and phosphorylates, the Med2 subunit of Mediator both in vivo and in vitro. A point mutation of the single phosphorylation site in Med2 results in a strongly reduced expression of the REP1, REP2, FLP1, and RAF1 genes, which are all located on the endogenous 2-microm plasmid. Combined with previous studies on the effects of SRB10/SRB11 deletions, Posttranslational modifications of Mediator subunits are important for regulation of gene expression.