FIG 12.

Both HCMV and EGF induce dextran uptake and activate macropinocytosis in SNB-19 cells, while HS-578T cells have high-level constitutively active macropinocytosis. (A and B) SNB-19 cells were serum starved for 5 h and then pretreated with EIPA (50 μM) or DMSO (the solvent for EIPA) at 37°C for 60 min. HCMV was added to the cells and incubated on ice for 45 to 60 min, followed by addition of 10-kDa dextran–Alexa 488 (A) or 70-kDa dextran–FITC (B) at 0.5 mg/ml. The temperature was then shifted to 37°C for 60 min. The cells were then treated with low-pH citrate buffer for 3 min and washed extensively with PBS, and uptake of dextran was quantified by FACS analysis. (C to E) HS-578T (C) or SNB-19 (D) cells were treated with 70-kDa dextran–FITC as described above. In parallel, the cells were treated with EGF at 50 ng/ml for 60 min at 37°C in the presence of 0.5 mg/ml 70-kDa dextran–FITC (E). (F) HS-578T cells were treated in the absence or presence of EIPA (50 μM) at 37°C for 60 min and then incubated with HCMV and dextran as described above.