Figure 5.

ApoB in lysosomal structures was increased by ALLN treatment. Bars, 10 μm. (A and B) Huh7 cells treated with 10 μM ALLN for 12 h. Many ApoB-positive structures were not colocalized with BODIPY493/503 (arrows in A), GM130 (B-left), or EEA1 (B-right). (C) Colocalization of ApoB (green) and Lysotracker (red) increased drastically after ALLN treatment. (D) Huh7 cells treated with 10 μM ALLN for the indicated times were incubated with 500 nM Lysotracker-Red for 2 h before fixation and immunolabeling. Colocalization of ApoB and Lysotracker-Red was quantified by measuring the number of double-positive pixels in confluent cells. Results of three independent experiments were averaged; statistical difference from the control (0 h) was examined by Student's t test (∗p < 0.05, ∗∗p < 0.001). (E and F) Immunogold labeling of ALLN-treated Huh7 cells. Bars, 0.2 μm. (E) Lysosomes (arrowheads) contained ApoB-positive electron-lucent particles (arrows) and adhered to the ApoB-crescent area adjacent to CLDs. (F) In some cases, the lysosomes containing ApoB labeling (arrows) wrapped around the ApoB-crescent and the adjacent CLD. The limiting membrane of the lysosome is marked by arrowheads.