Fig. 5. In HEK-293 cells endogenous Rab27 immunoreactivity is not enriched on lysosomes, but it is recruited to the WPB-like organelles induced by expression of VWF. HEK-293 cells were either mock transfected (A-D) or transfected with VWF (E-L); after 48 hours, they were fixed and processed for immunocytochemistry as described in Materials and Methods. The images shown are composite confocal images of Rab27 (A,E,I and green in D,H,L), LAMP1 (B,F,J and red in D,H,L) and VWF (C,G,K and blue in D,H,L) immunoreactivities. The same confocal parameters were used to collect the data for both groups (transfected and untransfected). (I-L) An enlarged area from (H) (outlined by the white box). Asterisk in (A) indicates immunoreactivity associated with the microtubule organizing centre. Arrows in (A,B) indicate the slight association of Rab27 immunoreactivity with a minority of the LAMP1-positive structures. Arrows in (E,G,I,K) indicate examples of co-localization between the VWF-positive structures and Rab27, and the arrowheads point to examples of VWF-positive structures that are negative for Rab27 immunoreactivity. Scale bars, 10 µm (D,H), 2 µm (L).