Fig. 5: Mitochondria associate with PDZD8- Rab7 labeled ER-endosome contacts. | Nature Communications

Fig. 5: Mitochondria associate with PDZD8- Rab7 labeled ER-endosome contacts.

From: PDZD8 interacts with Protrudin and Rab7 at ER-late endosome membrane contact sites associated with mitochondria

Fig. 5

a Correlative light and electron microscopy (CLEM) analysis indicates regions co-labeled with Rab7 and PDZD8 in cells are contacts between ER, late endosomes and mitochondria. Upper left panel: In-resin fluorescence images of U2OS cells expressing PDZD8-GFP (green), mCherry-Rab7 (red, mCh-Rab7) and MitoTracker DeepRed (magenta). Rectangle area on merged image corresponds to the magnified image under the panel (left middle), which is an overlay of the transmission electron micrograph and in-resin fluorescence images. Scale bars: 1 μm. Boxed regions, labeled 1–3 correspond to slices from 3D electron tomograms (upper and lower right and left images). Arrowheads in (1) indicate three membrane bilayers corresponding the late endosome membrane and two membranes of an ER tubule; Scale bar: 100 nm. Measured distance between the membranes of ER and LE is ~15 nm. Arrowheads in (2–3) mark the proximity of mitochondria to the ER-late endosome contact site. The CLEM experiment was repeated twice from independent samples of transiently transfected cells. TEM tilt-series for tomographic reconstruction were acquired from three individual cells that exhibited fluorescence of all three markers (PDZD8-GFP, mCherry-Rab7 and MitoTracker DeepRed). Scale bar: 100 nm. Late endosome (LE), mitochondria (M), and nucleus (N). b Mitochondria are persistently localized with late endosomes in contact with PDZD8 ER subregions. Time lapse GI-SIM imaging of BFP-Rab7 labeled endosomes in cells expressing PDZD8-GFP. Red arrow indicates a PDZD8-Rab7 mediated ER-LE-mitochondria contact site. Representative images from eight independent GI-SIM imaging sessions. Scale bar: 2 μm.

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