Med12 is a negative regulator of the Gli3-dependent sonic hedgehog signalling pathway via its interaction with Gli3 within the RNA polymerase II transcriptional Mediator. A complex is formed between Med12, Med13, CDK8 and CycC which is responsible for suppression of transcription. This subunit forms part of the Kinase section of Mediator [2].

1: Mediator modulates Gli3-dependent Sonic hedgehog signaling. Zhou H, Kim S, Ishii S, Boyer TG; Mol Cell Biol. 2006;26:8667-8682. PMID:17000779

2: A unified nomenclature for protein subunits of mediator complexes linking transcriptional regulators to RNA polymerase II. Bourbon HM, Aguilera A, Ansari AZ, Asturias FJ, Berk AJ, Bjorklund S, Blackwell TK, Borggrefe T, Carey M, Carlson M, Conaway JW, Conaway RC, Emmons SW, Fondell JD, Freedman LP, Fukasawa T, Gustafsson CM, Han M, He X, Herman PK, Hinnebusch AG, Holmberg S, Mol Cell. 2004;14:553-557. PMID:15175151