Summary
Ras-proteins are guanine nucleotide binding proteins, which, in the GTP bound state
emit a strong mitogenic signal. In the GDP bound state, the protein appears inactive.
We have found that stimulation by insulin of cells expressing elevated levels of insulin
receptors results in a rapid conversion of Ras-GDP into Ras-GTP. This process is part
of the signalling pathway leading to immediate-early gene expression and a mitogenic
response. There seems to be no involvement of Ras-GTP formation in the process of
insulin stimulated glucose transport. Though the precise mechanism by which Ras is
converted to the GTP bound state remains to be established, a tight correlation exists
between receptor autophosphorylation and Ras-GTP formation.
Key words
Ras - Insulin Receptor - Mitogenic Response - Glucose Uptake - Insulin
