The product of the retinoblastoma susceptibility gene has properties of a cell cycle regulatory element

Cell. 1989 Sep 22;58(6):1085-95. doi: 10.1016/0092-8674(89)90507-2.


The retinoblastoma susceptibility gene product, Rb, is suspected to suppress cell growth. Rb is a 110-114 kd nuclear phosphoprotein. We have previously demonstrated that SV40 T antigen binds only to unphosphorylated Rb, and not pp112-114Rb, the family of phosphorylated Rb. Here we demonstrate the cell cycle-dependent phosphorylation of Rb. In G0/G1 cells, virtually all the Rb is unphosphorylated. In contrast, during S and G2, it is largely, if not exclusively, phosphorylated. Rb phosphorylation occurs at the G1/S boundary in several cell types tested. A 14 residue peptide, corresponding to the SV40 T domain required for transformation, is able to compete effectively with SV40 T for binding to p110Rb. We propose a model to explain how Rb may suppress cell growth by acting as a cell cycle regulatory element.

MeSH terms

  • Adult
  • Amino Acid Sequence
  • Animals
  • Cell Cycle* / drug effects
  • Cell Line
  • Cells, Cultured
  • DNA Replication
  • Disease Susceptibility
  • Endothelium, Vascular / cytology
  • Eye Neoplasms / genetics*
  • Genes, Regulator*
  • HeLa Cells / cytology
  • Humans
  • Hydroxyurea / pharmacology
  • Molecular Sequence Data
  • Monocytes / cytology
  • Phosphoproteins / isolation & purification
  • Phosphoproteins / physiology*
  • Phosphorylation
  • Retinoblastoma / genetics*
  • Retinoblastoma Protein
  • Suppression, Genetic*
  • T-Lymphocytes / cytology
  • T-Lymphocytes / immunology


  • Phosphoproteins
  • Retinoblastoma Protein
  • Hydroxyurea