Effects of the ras-related rap2 protein on cellular proliferation.
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.
Jimenez
B
B
INSERM U-248 Faculté de Médecine Lariboisière-St. Louis, Paris, France.
Pizon
V
V
Lerosey
I
I
Béranger
F
F
Tavitian
A
A
de Gunzburg
J
J
D000818:Animals; D001483:Base Sequence; D002455:Cell Division / Q000235:genetics*; D002461:Cell Line, Transformed; D016336:Gene Products, vpr / Q000235:genetics / Q000378:metabolism*; D011905:Genes, ras; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D051381:Rats; D014162:Transfection
D016336:Gene Products, vpr