Immunofluorescence microscopy studies of the cellular distribution of TAT-SA. (A) HeLa cells were transfected with mutant AP180-C, a specific dominant-negative inhibitor of clathrin-mediated endocytosis, 24 h prior to transduction with TAT-SA-A488 (green) and clathrin-endocytosis marker TRITC-Transferrin (TRITC-Tf, red). Cells were fixed with PFA at 4 h post transduction, permeabilized with Triton-X and finally stained with antibody against myc-tagged AP180-C followed by an Alexa-633-conjugated anti-mouse antibody (purple). (B) The distribution of TAT-SA-A488 and lysosomal marker (red) was monitored in HeLa cells fixed (PFA) at 4 h post transduction and stained with an antibody against lysosomal marker LAMP-2 followed by an Alexa-546-conjugated anti-mouse antibody (red). Scale bars, 10 μm.