Figure 3.

GFP-tagged M11L localizes to mitochondria. COS-7 cells expressing GFP alone (a), M11L bearing an NH₂-terminal GFP tag (d), or a GFP-tagged, truncated form of M11L (GFP-M11Lstop) lacking the last 24 amino acids including the hydrophobic region (g) were visualized by confocal microscopy. Mitochondria were identified by Mitotracker Red staining (b, e, and h). When the Mitotracker Red fluorescence signal was merged with that of GFP-M11L, a yellow image was produced (f), indicating that GFP-M11L localizes to mitochondria in live, transfected cells. In contrast, no colocalization was observed in the case of GFP alone (c) or truncated M11L (i). Failure of truncated M11L to localize to mitochondria indicates that the last 24 amino acids are necessary for targeting. Bar, 10 nm.