Diverse Regulatory Functions of the E2F Family of Transcription Factors.

E2F activity is largely controlled by cell cycle dependent phosphorylation of the retinoblastoma family of proteins (e.g., pRB). Regulation of E2F transcription factors by RB-family proteins is crucial to the regulation of cell cycle entry. In addition to masking E2F activation of transcription, pRB family proteins have been implicated in nucleating transcriptional repressor complexes containing E2F transcription factors on cell cycle regulated promoters. More recently E2F transcription factors have been shown to regulate the activity of cellular processes in differentiation and apoptosis in a manner that is independent of cell cycle control. These recent findings have revealed that E2F transcription factors participate in noncell cycle regulatory mechanisms. [ABSTRACT FROM AUTHOR]