Figure 6.

Birbeck granule formation requires the presence of both Langerin and Rab11A. M10-22E cells, comicroinjected with siRNA against Rab11A and Texas Red-dextran (A and B, left [red]), were incubated with (B) or without (A) 50 μM chloroquine, as described in Materials and Methods. The cells were then immunolabeled with an anti-Rab11 serum (middle, green) and the anti-Langerin mAb DCGM4 (right, blue). Merged images are shown in A and B. Bars, 10 μm. (C) Many BGs (arrows) are present in the cytosol, either isolated or continuous with and/or in the close vicinity of multivesicular compartments (see inset and the BGs visible in the top right-hand corner). (D) Many BGs, some of them particularly long, are also present in the perinuclear (Nu) and Golgi (G) areas. The multivesicular compartment visible in the middle on the right and indicated with a star is viewed from different angles in F. Note that the two structures (arrows) on either side of this multivesicular endosome are BGs (F, top and bottom). (E) In cells treated with both siRNA against Rab11A and chloroquine, BGs are absent from the pericentriolar area and the limiting membranes of the multivesicular compartments. Bars, 0.5 μm.