Fig. 6. NRK transfectants expressing CD63-GFP, FasLWT-GFP, FasLpro-GFP, and FasL74-GFP were incubated for 30 minutes on ice with the relevant primary antibody (anti-CD63 for cells expressing CD63-GFP and Nok-1 for cells expressing FasL-GFP (WT, pro and 74)) or an irrelevant isotype-matched control antibody (data not shown). The antibody was replaced with fresh media and the cells were returned to 37°C for 120 minutes, after which they were stained with the relevant Texas-Red-conjugated secondary antibody and analysed by confocal microscopy. The images have been merged (C,F,I,L); yellow signal demonstrates endocytosed antibody. No endocytosis was seen with the control antibody. Bars, 10 mm.