DRTF1/E2F (DP1/E2F)

Function

• role in the control of cell-cycle progression from G1 to S phase
• appears to mediate both cell proliferation & apoptosis
• binds to E2F site
• the complex can interact with hypophosphorylated RB1 & related proteins (RBL1 & RBL2) that inhibit the E2F transactivation domain
• this repression involves recruitment of histone deacetylase
• during the cell cycle, from mid-to-late G1 phase, RB family members become phosphorylated, detach from DRTF1/E2F to render E2F transcriptionally active
• viral oncoproteins, notably E1A, T-antigen & HPV E7, are capable of sequestering RB protein, thus releasing the active complex
• RB1 inhibits the transcriptional activity of DRTF1/E2F during cell cycle progression
• when mutant RB1 is present, DRTF1/E2F is deregulated
• binding to RB1 & RB-related protein p107 inhibits DNA-binding activity of DRTF1/E2F
• E2F/DP transactivation can be mediated by several cofactors including TBP, TFIIH, MDM2 & CBP

More general terms

• transcription factor complex
• DNA-binding protein