Extended Data Fig. 4: Relative movements between sub-organellar structures observed by dual-color Sparse-SIM. | Nature Biotechnology

Extended Data Fig. 4: Relative movements between sub-organellar structures observed by dual-color Sparse-SIM.

From: Sparse deconvolution improves the resolution of live-cell super-resolution fluorescence microscopy

Extended Data Fig. 4

(a) The inner and outer mitochondrial membranes (OMMs and IMMs) labeled with Tom20–mCherry and Mito-Tracker Green in a live COS-7 cell. (b) Magnified views from the white box in (a). (c) Intensity profiles of OMMs (magenta) and IMMs (cyan) along the continuous and dashed lines in (b), with mitochondrial configurations shown in the right. Sparse-SIM readily detected two types of OMMs:IMMs configurations: a long crista extended from one side to ~142 nm away from the other side of the OMMs, and a short crista extended only ~44 nm towards the other side of the OMMs (Supplementary Video 7). (d) Average FRC resolutions (n = 10). (e) The white dashed box in (a) is enlarged and shown at three time points. It revealed rare events: the IMMs extension not being enclosed within the Tom20-labeled structures in a few frames. This result might be explained by the non-homogenous distribution of Tom20 protein on the OMMs. (f) A representative example of both the IMMs (cyan) and ER (magenta, Sec61β-mCherry). As shown in the inset, we found that ER tubules randomly contacted the mitochondria with equal probability at both the cristae regions and the regions between cristae. (g) Magnified views from the white box in (f). We found that the contact between one ER tubule and the top of a mitochondrion not only correlated with the directional movement of the latter but also the synergistically rearranged orientations of cristae thereafter (Supplementary Video 8). Centerline, medians; limits, 75% and 25%; whiskers, maximum and minimum; error bars, s.e.m; Experiments were repeated five times independently with similar results. Scale bars: (a, f) 1 μm; axial: 0.2 arbitrary units (a.u.); lateral: 100 nm; (b, e and g) 500 nm.

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