Functions in cell cycle regulation. Component of the DREAM complex, a multiprotein complex that can both act as a transcription activator or repressor depending on the context. In follicle cells, the complex plays a central role in the site-specific DNA replication at the chorion loci. During development, the complex represses transcription of developmentally controlled E2F target genes. Forms a complex with the DRTF1/E2F transcription factor through binding to a C-terminal region of E2F. This binding inhibits the E2F-mediated transactivation activity. Component of the DREAM complex at least composed of Myb, Caf1-55, mip40, mip120, mip130, E2f2, Dp, Rbf, Rbf2, lin-52, HDAC1/Rpd3 and l(3)mbt. Expressed at constant levels throughout embryo and larval development (at protein level). Phosphorylation by cyclin E-dependent kinases appears to negatively regulate RBF activity. Belongs to the retinoblastoma protein (RB) family.