Effects of the ras-related rap2 protein on cellular proliferation

Int J Cancer. 1991 Sep 30;49(3):471-9. doi: 10.1002/ijc.2910490327.


Ras oncogenes encode 21-kDa (p21s) GTP binding proteins that are capable of transforming immortalized cells in culture. The ras-related rap1A/Krev-1/smgp21A protein, that exhibits a similar structural organization and contains the same effector domain as ras proteins, antagonizes ras-transformation. In order to investigate whether the closely related (61% identical) rap2 protein had similar capacities, the corresponding cDNA was inserted into constitutive as well as inducible mammalian expression vectors. Neither the wild-type, nor an "activated" mutant carrying a glycine-to-valine substitution at position 12, had any transforming activity. Several independent lines of evidence demonstrate that the rap2 protein exhibits neither growth-promoting nor growth-inhibitory effects, and that its over-expression does not interfere with ras-induced transformation. Thus, in spite of their great similarities, the rap1A/Krev-1/smgp21A and rap2 proteins have distinct physiological properties.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • Cell Division / genetics*
  • Cell Line, Transformed
  • Gene Products, vpr / genetics
  • Gene Products, vpr / metabolism*
  • Genes, ras*
  • Molecular Sequence Data
  • Mutation / genetics
  • Phenotype
  • Rats
  • Transfection


  • Gene Products, vpr