A Time-lapse microscopic images showing that H1299 shCtr or shM2 cells stably expressing Mito-GFP were connected by TNTs containing mitochondria. Cells were seeded in collagen-coated dishes and cultured for 24 h before time-lapse life cell images were acquired by confocal microscopy (also see Movies EV1 and EV2). Fluorescent images (with bright field) at different time points show the mitochondria moving along the TNT and entering in one of the two connected cells. Scale bar: 20 μm. The moving mitochondria are marked by the white arrows. Boxed areas (shCtr in yellow dotted boxes; shM2 in red dotted boxes) are enlarged and shown in the middle panel. B Confocal microscopic images of control and shM2 H1299 cells following immunofluorescence staining with anti-Tom20 antibody (green) and staining using phalloidin (red). The white arrows marked TNTs, whereas the white triangles marked mitochondria inside TNTs. Scale bar: 25 μm. C Data information: nuclei were stained with Hoechst 33342 (blue). 