Arc32, or Med8, is one of the subunits of the Mediator complex of RNA polymerase II. The region conserved contains two alpha helices putatively necessary for binding to other subunits within the core of the Mediator complex [1]. The N-terminus of Med8 binds to the essential core Head part of Mediator and the C-terminus hinges to Med18 on the non-essential part of the Head that also includes Med20 [3].

1: Analysis of Schizosaccharomyces pombe mediator reveals a set of essential subunits conserved between yeast and metazoan cells. Spahr H, Samuelsen CO, Baraznenok V, Ernest I, Huylebroeck D, Remacle JE, Samuelsson T, Kieselbach T, Holmberg S, Gustafsson CM; Proc Natl Acad Sci U S A 2001;98:11985-11990. PMID:11572939

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

3: Structure-system correlation identifies a gene regulatory Mediator submodule. Lariviere L, Seizl M, van Wageningen S, Rother S, van de Pasch L, Feldmann H, Strasser K, Hahn S, Holstege FC, Cramer P; Genes Dev. 2008;22:872-877. PMID:18381891