Code:71-171
Retinoblastoma protein (Rb) the tumor suppressor product of the retinoblastoma susceptibility gene is a 110 kDa protein that functions as a negative regulator of the cell cycle by arresting cells in the G1 phase and halting inappropriate cell proliferation (1). At the transcriptional level Rb protein exerts its growth suppressive function by binding to transcription factors including E2F1 PU1 ATF2 UBF Elf-1 and c-Abl (2-4). Loss of Rb function leads to uncontrolled cell growth and tumor development and is found in all retinoblastomas and in a variety of other human malignancies. The ability of Rb protein to inhinbit transcription and cell cycle progression is inactivated by phosphorylation which is catalyzed by the cyclin-dependent protein kinases
|