Figure 1. CXCR7 mediated EGFR transactivation is independent of Gαi/o and EGF-like ligands.
Growth factor starved RWPE-1 (A), RWCX7 (B) or LNCaP cells (C) were pretreated with Pertussis toxin (B. pertussis, PTX, 0.5 μg/ml) for 2 hr at 37 °C or left untreated and then incubated in presence or absence of EGF (10 ng/ml) for 2 or 5 min at 37 °C. Total cell lysates were collected and subjected to Western blot analysis using antibodies to phosphorylated and total EGFR and ERK1/2. D, E: RWCX7 cells (RWPE-1 cells stably expressing CXCR7) (D) or LNCaP cells (E) were growth factor starved for 16 hr and then pre-incubated with Amphiregulin (Amp) for 4 hr followed by incubation in presence or absence of EGF (10 ng/ml, 5 min). Cell lysates were analyzed by western blotting using anti-phospho-EGFR and anti-ERK1/2 antibodies. Growth curves for starved and non-starved cells are shown in the right panels.