Figure 2: Oncogenic K-Ras-dependent activation of WT H-Ras is mediated by the allosteric stimulation of Sos.
From: Sos-mediated cross-activation of wild-type Ras by oncogenic Ras is essential for tumorigenesis
(a) MIA PaCa-2 cells stably expressing inducible miR-30-based shCtrl or shSos were infected with lentiviral inducible *SosWT or *SosRA/LE. Following doxycycline treatment, cells were serum-starved for 20 h and H-Ras-GTP levels were measured using the RBD pull-down assay. (b) The levels of activated Ras were quantified by densitometry scanning and normalized to the levels of total H-Ras. Values are means±s.d. from three independent experiments presented as fold activation compared with shCtrl. (c) MIA PaCa-2 cells stably expressing inducible miR-30-based shCtrl or shSos were infected with lentiviral inducible *SosWT in the presence or absence of shK-Ras. H-Ras-GTP levels were measured using the RBD pull-down assay. (d) The levels of activated Ras were quantified by densitometry scanning and normalized to the levels of total H-Ras. Values are means±s.d. from three independent experiments presented as fold activation compared with shCtrl. For all panels, the efficiency of Sos suppression was analysed by western blotting and tubulin was used as a loading control. WCL, whole cell lysate; A.U., arbitrary units.
