SV40 large T antigen binds preferentially to an underphosphorylated member of the retinoblastoma susceptibility gene product family

Cell. 1989 Jan 13;56(1):57-65. doi: 10.1016/0092-8674(89)90983-5.


Extracts of monkey cells (CV-1P) synthesizing SV40 large T antigen (T) were immunoprecipitated with monoclonal antibodies to T or p110-114Rb, the product of the retinoblastoma susceptibility gene (Rb). While a family of p110-114Rb proteins can be detected in anti-Rb immunoprecipitates, only one member of this family, p110Rb, was found in anti-T precipitates of these extracts. Identical results were obtained with extracts of CV-1P cells which had been previously mixed in vitro with highly purified T. The p110-114Rb family is composed of two sets--p110Rb, an un- or under-phosphorylated species, and pp112-114Rb, a group of overtly phosphorylated proteins. Thus, T bound preferentially to the un- or underphosphorylated member of the family. In addition, T failed to alter the relative abundances of these species. These results suggest a model in which the growth suppression function of Rb is down modulated either by phosphorylation or T antigen binding.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Antigens, Polyomavirus Transforming / immunology
  • Antigens, Polyomavirus Transforming / metabolism*
  • Blotting, Western
  • DNA-Binding Proteins / metabolism*
  • Electrophoresis, Polyacrylamide Gel
  • Humans
  • In Vitro Techniques
  • Macromolecular Substances
  • Molecular Weight
  • Nuclear Proteins / immunology
  • Nuclear Proteins / metabolism*
  • Phosphoproteins / immunology
  • Phosphoproteins / metabolism*
  • Precipitin Tests
  • Protein Binding
  • Retinoblastoma / genetics*


  • Antigens, Polyomavirus Transforming
  • DNA-Binding Proteins
  • Macromolecular Substances
  • Nuclear Proteins
  • Phosphoproteins