Figure 5From: Emergence of bimodal cell population responses from the interplay between analog single-cell signaling and protein expression noiseConfirming the presence of negative feedback. HEK293 cells were pretreated with 5 ÎŒM U0126 or vehicle alone (DMSO) for 30 min prior to stimulation with 0.1 nM, 1 nM or 10 nM of EGF (A) or TGFα (B) for 5 or 30 minutes. Control cells were left unstimulated (â). Total cell lysates were assayed for activated RasGTP as described in âMaterials and Methodsâ section. IP denotes the pull-down fraction, TCL denotes total cell lysate, and IB denotes immunoblot.Back to article page