Colocalization of GST-PFO with LAMP-1 and filipin in NPC fibroblasts. Cholesterol visualized by GST-PFO (red) is present in lysosomes identified by anti-LAMP-1 (green in A’-A”) and filipin (blue in B’-B”). (A”s1-s4) Merged images of optical sections of the cell shown in (A-A”). The sections range from the basolateral (A”s1) to the apical (A”s4) part of the cell. (A”, B”) Merged images of (A-A’) and (B-B’), respectively. Colocalization of GST-PFO and LAMP-1 is seen as yellow color in (A” and A”s1-s4) while pink color reflects colocalization of GST-PFO- and filipin-positive structures in (B”). Scale bars, 20 μm.