Dansylcadaverine inhibits internalization of 125I-epidermal growth factor in BALB 3T3 cells

The binding and internalization of 125I-epidermal growth factor (125I-EGF) was studied in cultures of BALB 3T3 cells using a novel method that involved removal of cell-surface hormone by treatment with acetic acid under conditions that did not remove internalized hormone. In control cultures, 125I-EGF initially bound to its receptor on the plasma membrane and then was rapidly internalized. After 30 min, only 15% of the cell-bound hormone remained on the surface. In contrast, cultures treated with dansylcadaverine retained 82% of the cell-bound hormone on the cell surface. We propose that dansylcadaverine inhibits EGF internalization by preventing it from clustering in clathrin-coated pits.