The overall function of the full-length Med25 is efficiently to coordinate the transcriptional activation of RAR/RXR (retinoic acid receptor/retinoic X receptor) in higher eukaryotic cells. Human Med25 consists of several domains with different binding properties, the N-terminal, VWA domain which is this one, an SD2 domain from residues 229-381, a PTOV(B) or ACID domain from 395-545, an SD2 domain from residues 564-645 and a C-terminal NR box-containing domain (646-650) from 646-747. This VWA or von Willebrand factor type A domain when bound to RAR and the histone acetyltransferase CBP is responsible for recruiting Med1 to the rest of the Mediator complex [3].

1: The activator-recruited cofactor/Mediator coactivator subunit ARC92 is a functionally important target of the VP16 transcriptional activator. Yang F, DeBeaumont R, Zhou S, Naar AM; Proc Natl Acad Sci U S A. 2004;101:2339-2344. PMID:14983011

2: Purification of a plant mediator from Arabidopsis thaliana identifies PFT1 as the Med25 subunit. Backstrom S, Elfving N, Nilsson R, Wingsle G, Bjorklund S; Mol Cell. 2007;26:717-729. PMID:17560376

3: MED25 is distinct from TRAP220/MED1 in cooperating with CBP for retinoid receptor activation. Lee HK, Park UH, Kim EJ, Um SJ; EMBO J. 2007;26:3545-3557. PMID:17641689