Figure 4

Role of mitofusins (Mfn1/2) on vMIA trafficking and clustering on mitochondria. (a) Mfn1/2-null MEFs were transiently transfected to express vMIA-CFP (pseudocolored green) and Tom20-mCherry (red) and imaged by confocal microscopy. The images show a single confocal plane from a deconvolved z-stack presented as monochrome images of the individual channels, which are pseudocolored for the merged image, and the boxed region marks the region zoomed in the inset. (b) The fluorescence lifetime comparison of cytosolic EGFP (τ = 3.46 ± 0.015 ns, n = 150 regions from 15 cells) and vMIA-EGFP (τ = 3.10 ± 0.011 ns, n = 130 regions from 13 cells) in Mfn1/2-null MEFs. (c) A single plane from an MSIM z-stack images showing clustered distribution of vMIA-EGFP on the OMM of an Mfn1/2-null MEF. A zoom of mitochondria shows vMIA clustering. (d) The number of vMIA clusters/µm of the OMM in WT MEFs (n = 50) and Mfn1/2-null MEFs (n = 40) are shown. (e) Normalized intensity profile along the solid line shown in the zoomed inset in panel c. (f) The FWHM of vMIA clusters (n = 40) in Mfn1/2-null MEFs were measured and plotted. The line and red cross mark indicate the median and mean, respectively. ****Represents p < 0.0001.