Fig. 2.

LY6E and RNASEK facilitate size-dependent endocytosis. (A and B) Biotin-conjugated transferrin (25 μg/mL) was added to siRNA-treated U2OS cells for the indicated times. (A) Images are representative of three independent experiments. (B) Quantification of transferrin (Tf) uptake; n = 3, mean ± SEM, **P < 0.01. (C) Schematic of bead uptake assay. (D and E) Transferrin-conjugated GFP beads were added to siRNA-transfected U2OS cells for 45 min before fixation. Nonpermeabilized cells were then treated with streptavidin-594. (D) Images are representative of three independent experiments. Arrows show internalized beads (green only). (E) Quantification of transferrin-conjugated bead uptake (Mander’s colocalization analysis); n = 3, mean ± SEM, *P < 0.05. n.s., not significant. (Magnification: 63×.)