Uptake and turnover of His-ILFAC. His ILFAC and His-FAC (10 μg/mL of cells; lane 1) were bound to HSC536 lymphoblasts at 4°C, internalized by warming to 37°C, and the intracellular fate of the fusion proteins was assessed by Western analysis with anti-FAC antibody after 5 minutes (lane 3), 15 minutes (lane 4), 30 minutes (lane 5), 60 minutes (lane 6), 120 minutes (lane 7), and 240 minutes (lane 8) postbinding times. Lane 2, no recombinant protein added.