Fig. 4.

Increased membrane contact sites in CHO M12 cells after AnxA6 depletion. a Representative transmission electron microscopy (TEM) images of late endosomes/lysosomes (LE/Lys) from CHO-WT, CHO M12 expressing control siRNA (siRNA Ctrl), siRNA targeting AnxA6 (siRNA AnxA6) and CHO M12-A6ko cells. Arrowheads indicate endoplasmic reticulum (ER). A schematic representation of these images with highlighted membrane contacts (purple) between ER and LE/Lys structures is shown. b Quantitative stereology of ER–LE/Lys contacts in TEM sections is given: perimeter of LE/Lys contacts (in microns) and percentage of endosome surface in contact with the ER per cell (n > 30). LE late endosomes, ER endoplasmic reticulum, Mit mitochondria, PM plasma membrane. Scale bar, 200 nm. *p < 0.05; ***p < 0.001 by one-way ANOVA with Bonferroni post hoc test. All data are presented as mean ± SD in red