Figure 4. EGFR signaling via promoting glucose uptake upregulates SCAP and activates SREBP-1.
(A, B) Confocal microscopy images of SREBP-1 subcellular distribution (A), or western blot analysis of SREBP-1 cleavage (B) in U87/EGFR cells in response to EGF (50 ng/ml) in the presence or absence of glucose (5 mM) for 12 hr. Scale bars, 20µm. SREBP-1 nucleus intensity was quantified over 30 cells by using ImageJ. The results are shown as mean ± SEM (n = 30). Significance was determined by an unpaired student t test.
(C) Glucose uptake analysis of U87/EGFR cells in response to EGF (50 ng/ml) by using 14C-glucose isotope. The results are shown as mean ± SEM (n=3). Significance was determined by an unpaired student t test.
(D) Western blot analysis of cell membrane and nuclear extracts from U87/EGFR cells in response to EGF (50 ng/ml) stimulation in the presence or absence of glucose (5 mM) for 12 hr.
(E) Western blot analysis of U87/EGFR cells after knockdown of SCAP in comparison with shRNA control (shCtrl) in response to EGF (50 ng/ml) stimulation in the presence of glucose (5 mM) for 12 hr.
See also Figure S4.