Figure 3.

Validation of MERC proteins by fluorescence imaging in living cells

(A–D) Fluorescent images of living cells. U2OS cells were transiently transfected with ER-DsRed along with plasmids expressing WFS1-EGFP (A), BAG2-EGFP (B), SPTLC1-EGFP (C), or GLUD1-EGFP (D). The cells were then grown on coverslips to allow adherence and spreading. MitoTracker (deep red) was used to label mitochondria, and live cell images were taken at the indicated intervals with LSM 980 confocal microscopy equipped with a 63×/1.40 NA oil immersion objective (Zeiss). The smaller images were amplification of the boxed regions in the larger images. The upper images show overlap between mitochondria and ER. The lower images are merged images of the three channels. White arrows indicate mitochondria-ER contacts. Scale bar, 5 μm. See also Figure S4. Candidates, green; ER, magenta; blue, mitochondria.