Transcriptional activator that binds to E2F sites, these sites are present in the promoter of many genes whose products are involved in cell proliferation. May mediate growth factor-initiated signal transduction. It is likely involved in the early responses of resting cells to growth factor stimulation. Specifically required for multiciliate cell differentiation: together with MCIDAS and E2F5, binds and activate genes required for centriole biogenesis. Component of the DRTF1/E2F transcription factor complex. Binds cooperatively with DP-1 to E2F sites. Interaction with retinoblastoma protein RB1 or proteins RBL1 and RBL2 inhibits the E2F transactivation domain. Component of the DREAM complex (also named LINC complex) at least composed of E2F4, E2F5, LIN9, LIN37, LIN52, LIN54, MYBL1, MYBL2, RBL1, RBL2, RBBP4, TFDP1 and TFDP2. The complex exists in quiescent cells where it represses cell cycle-dependent genes. It dissociates in S phase when LIN9, LIN37, LIN52 and LIN54 form a subcomplex that binds to MYBL2 (By similarity). In the developing epidermis, first detected in 13.5-14.5 dpc embryos. With the appearance of stratified epithelium, levels of E2F5 expression increase and by 16.5 dpc, high expression found in the suprabasal cell layers. High expression also found in other regions with stratified squamous epithelia including the developing palate, lip and tongue. In the developing nervous system, first detected in the forebrain at 9.5 dpc. At 10.5 dpc, strongly expressed in the rostral region of the spinal cord. By 11.5 dpc, E2F5 is expressed throughout the developing central nervous system. In 12.5-15.5 dpc embryos, expression found in the undifferentiated ventricular regions of the brain. In the retina, expressed, in 14.5-18.5 dpc embryos, in the retinoblastic cell layer. In other developing tissues, highly expressed in the choroid plexus. Also found in the kidney, liver, lung, heart and weakly, in developing skeletal muscle and chondrocytes. Belongs to the E2F/DP family.