EAPP Background Information
E2F transcription factors play a major role in apoptosis and cell proliferation and are found to be frequently deregulated in cancers. Through interactions with cell cycle regulators such as cyclins, cyclin-dependent kinases and retinoblastoma protein (Rb), E2F family members also integrate cell cycle progression. EAPP (E2F-associated phosphoprotein) is a 285 amino acid highly phosphorylated nuclear protein that fine-tunes E2F activities by interacting with E2F-1, E2F-2 and E2F-3, but not E2F-4. By binding to the N-terminal domain of these E2F family members, EAPP interferes with the binding of cyclin A, Sp1 transcription factors, EBP1 and EBP2, therefore influencing E2F activity. Interestingly, EAPP is expressed during the cell cycle, but disappears during mitosis, suggesting that this step is necessary to complete the cell cycle. EAPP is ubiquitously expressed, with highest levels found in placenta, pancreas, skeletal muscle and heart.
