Rb Gene Protein

Retinoblastoma gene protein (RB1) is a negative regulator of the cell cycle, which has dephosphorylated active form or phosphorylated inactive form. In G0 and G1 phases, dephosphorylated RB1 can bind to transcription factor E2F to prevent its activation of cell cycle progression genes. In S phase, RB1 is phosphorylated by the complex composed of cyclin and cyclin dependent kinase (CDK), and then releases E2F to promote the operation of the cell cycle. Some research has found that RB1 has tumor inhibitory effect, and its down-regulation is closely related to the occurrence of various tumors, including retinoblastoma, osteosarcoma, liver cancer, lung cancer, colorectal cancer, prostate cancer, breast cancer, ovarian cancer, etc. Its expression deletion or functional inactivation may be caused by RB gene mutation or combination with oncoprotein. However, the relationship between RB1 and tumor development, as well as patient prognosis, is currently inconclusive.