Figure 3. Mitochondrial clusters induced by proline variants do not have connected mitochondrial network.

(A) Representative images of Mfn1-null MEFs expressing mt-paGFP and transduced with an empty vector (V), Mfn1^WT-FLAG, or Mfn1^S329P-FLAG either 0 or 50 min after activation of mt-paGFP with a 405-nm laser, which is time = 0. Mitochondria were labeled with MitoTracker Red CMXRos and visualized with live-cell fluorescence microscopy. Images represent maximum intensity projections. Scale bar = 5 μm. (B) Representative images of Mfn2-null MEFs expressing mt-paGFP and transduced with an empty vector (V), Mfn2^WT-FLAG, or Mfn2^S350P-FLAG either 0 or 50 min after activation of mt-paGFP with a 405-nm laser, which is time = 0. Mitochondria were labeled with MitoTracker Red CMXRos and visualized with live-cell fluorescence microscopy. Images represent maximum intensity projections. Scale bar = 5 μm. (A, C) Quantification of the diffusion of mt-paGFP in the cell lines described in (A) and in wild-type MEFs (Mfn1^+/+Mfn2^+/+) transduced with an empty vector (V), Mfn1^WT-FLAG, or Mfn1^S329P-FLAG. Error bars represent mean ± SEM. n = 6/7 cells over two independent experiments. (B, D) Quantification of the diffusion of mt-paGFP in the cell lines described in (B) and in wild-type MEFs (Mfn1^+/+Mfn2^+/+) transduced with an empty vector (V), Mfn2^WT-FLAG, or Mfn2^S350P-FLAG. Error bars represent mean ± SEM. N = 9–11 cells over three independent experiments.