New work shows that activation of the Ras guanine nucleotide exchange factor SOS is dependent upon the membrane density of phosphatidylinositol-4,5-bisphosphate (PIP 2) and GTP-bound Ras.

Comparison of these structures revealed the full catalytic mechanism by which DOCK proteins mediate the release of GDP from the GTPase, and then how the subsequent binding of GTP stimulates the ...

The GDI can be displaced by a GDI-displacement factor (GDF), and the GDP-bound Rab protein is then recruited back to the membrane and activated by a guanine nucleotide-exchange factor (GEF).

SOS1 is a guanine nucleotide exchange factor (GEF) that activates KRAS, and recent preclinical studies have demonstrated that combining KRAS and EGFR inhibitors with SOS1 inhibitors can overcome ...