Fig. S2.

Examples of mitochondrial fusion events. (A) Diverse orientation fusion events in freshly isolated in vivo-transformed AVCMs. (Upper) Images of time series showing sequential fusion events in both transverse and longitudinal orientations. (Lower) Quantitative evaluation of mtPA-GFP fluorescence transfer between numbered organelles. (B) Sequential mitochondrial fusion events in NCVMs. (Left) A 5 × 5-μm region of mtPA-GFP PA. (Center) Zoom-in view of the rectangle denoted by the white-dashed line showing the time course of mitochondrial fusion events between mitochondria 1 and 2, followed by matrix mixing between mitochondria 2 and 3. (Right) Quantification of mtPA-GFP fluorescence transfer from donor 1 to acceptor 2, and concomitant mixing of mtDsRed from 2 to 1 (the latter was photobleached when mtPA-GFP was photoactivated by 2P illumination). At 100 s after the first event, a new two-way mitochondrial mixing is evidenced between mitochondria 2 and 3. (C) Mitochondrial fusion event in an in vitro- transformed, 48-h–cultured AVCM. (Upper) The area of PA. (Lower) Time series of a fusion event between two neighbor mitochondria. Quantification of mtPA-GFP mixing is shown in the bar chart, highlighting the changes in the PA-GFP levels between donor and acceptor mitochondria before and after the fusion event.