FunctionComponent of the Mediator complex, a coactivator involved in the regulated transcription of nearly all RNA polymerase II-dependent genes. Mediator functions as a bridge to convey information from gene-specific regulatory proteins to the basal RNA polymerase II transcription machinery. Mediator is recruited to promoters by direct interactions with regulatory proteins and serves as a scaffold for the assembly of a functional preinitiation complex with RNA polymerase II and the general transcription factors.
Tissue specificityUbiquitously expressed.
Sequence similaritiesBelongs to the Mediator complex subunit 1 family.
Post-translational modificationsPhosphorylated by MAPK1 or MAPK3 during G2/M phase which may enhance protein stability and promote entry into the nucleolus. Phosphorylated upon DNA damage, probably by ATM or ATR.
Cellular localizationNucleus. A subset of the protein may enter the nucleolus subsequent to phosphorylation by MAPK1 or MAPK3.