Mediator of RNA polymerase II transcription subunit 6 is one of the subunits of the Mediator complex. It is an enzyme that in humans is encoded by the MED6 gene. Component 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.