Fig. 5
From: Feedback activation of neurofibromin terminates growth factor-induced Ras activation
Feedback-mediated stimulation of neurofibromin mediates Ras deactivation. a EGF-induced Ras activation in HeLa cells subjected to previous siRNA-mediated silencing of RASA1. siRNA-transfected cells were additionally treated with the MEK inhibitor U0126 in order to ascertain that siRNA transfections did not distort the feedback mechanism of Ras deactivation. b Same experiment as in (a) in DAB2IP-silenced HeLa cells. c Same experiment as in (b) performed in neurofibromin-silenced HeLa cells. d Time course of EGF-driven Ras activation in HEK293T cells and a derivative line with stable shRNA-mediated knockdown of neurofibromin. e HeLa cells subjected to siRNA mediated silencing of neurofibromin were challenged with EGF. Cells were permeabilized prior to or 5 and 20Â min after EGF stimulation and processed for the analysis of nucleotide exchange on Ras