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. The Mediator complex, having a compact conformation in its free form, is recruited to promoters by direct interactions with regulatory proteins and serves for the assembly of a functional preinitiation complex with RNA polymerase II and the general transcription factors. Involved in the regulation of the circadian clock, in the control of flowering time, in freezing- and osmotic-stress tolerance and in both salicylic acid- and jasmonate-mediated defense gene expression. Component of the Mediator complex. Not up- or down-regulated by cold. Late flowering in long days. Very low expression of cold-responsive (COR) genes. Belongs to the plant Mediator complex subunit 16 family.