Quantification of internalized TAT-SA in living HeLa cells. (A) Quantitative analysis of the colocalization between both TAT-SA-A488 and TRITC-labeled transferrin and TRITC-labeled dextran (10 kD) at 15 min post transduction. (B) The relative fluorescence intensity of internalized TAT-SA-A488 was measured in cells treated with cytochalasin D (cytD), amiloride (ami) or nocodazole (noco) at 4 h post transduction. Control cells (C) were untreated. The fluorescence intensity data was collected from multiple series of cells by confocal microcopy and processed with the 3D LSM program.