Fig. 10. Tfn internalization in control, Syt IX-overexpressing and Syt IX-suppressed RBL cells. RBL-Syt IX^– (A,D,G), control (B,E,H) and RBL-Syt IX⁺ (C,F,I) cells were grown on glass coverslips, serum starved for 1 hour and incubated with Texas-Red-conjugated Tfn (TR-Tfn, 50 µg/ml) for 1 hour at 4°C. Cells were subsequently left on ice (A-C) or warmed up to 37°C for 5 (D-F) or 30 (G-I) minutes. Cells were subsequently visualized by confocal microscopy as described under Materials and Methods. Bars, 13 µm.