Fig. 7. Alix depletion affects LBPA but not CD63 levels in multivesicular endosomes. Subcellular localisation of LBPA and CD63 in control (A,C) and Alix-siRNA-treated (B,D) cells. Cells were labelled with monoclonal antibodies against LBPA and CD63 followed by a rabbit anti-mouse antibody and 15 nm proteinA gold. In control cells, LBPA was found in typical MVBs and multilamellar late endosomes. Less staining was observed in Alix-siRNA-treated cells. CD63 labelling was also found in MVBs and late endosomes. Quantitation of the labelling intensity (E,F) indicated that total cell and endosomal LBPA content was significantly reduced, whereas CD63 levels were close to control values. Scale bars: 200 nm.