Component of the srb8-11 complex. The srb8-11 complex is a regulatory module of the Mediator complex which is itself involved in regulation of basal and activated RNA polymerase II-dependent transcription. The srb8-11 complex may be involved in the transcriptional repression of a subset of genes regulated by Mediator. It may inhibit the association of the Mediator complex with RNA polymerase II to form the holoenzyme complex. Component of the srb8-11 complex which consists of rb8, srb9(TRAP240), srb10 and srb11. The srb8-11 complex associates with the Mediator complex thereby blocking association with RNA polymerase II and leading to reduced transcriptional activation by Mediator. Belongs to the Mediator complex subunit 12 family.