Temperature- and CD33-dependent uptake of His-M195FANCF by EUFA698 cells.

Purified His-M195FANCF (30 μg) was added to parental or CD33⁺ EUFA698 cells (1 × 10⁶/mL) as indicated. In parallel experiments, cells were preincubated with 0.25% trypsin for 10 minutes at 37°C to reduce the surface expression of CD33 before addition of the fusion protein. After 10 minutes at 4°C, cells were warmed to 37°C, and internalization of the fusion protein (arrow) was assessed by Western blotting of total cellular lysates using anti-FANCF antibodies.