Specific internalization
of the FGF2 WT and FGF2-vcMMAE conjugates
into the cells expressing FGFR1. Shown are the representative images
of internalization of FGF2 WT, KCK-FGF2[C78S/C96S]-(vcMMAE)1, or KCK-FGF2-(vcMMAE)3 into U2OS-R1 cells vs U2OS cells.
Equal numbers of U2OS cells stably stained with CellTrace Violet (blue)
and U2OS-R1 (nonstained) were grown together and then incubated with
1000 ng/mL FGF2 WT, KCK-FGF2[C78S/C96S]-(vcMMAE)1, or KCK-FGF2-(vcMMAE)3 labeled with DyLight550 (red) at 37 °C for 15 min. The
cells were fixed, stained with anti-EEA1 antibody (green), and examined
by confocal microscopy. U2OS-R1 cells are marked with a dashed line.
The bar corresponds to 10 μm.