Fig. 4. GFP fusions of CHMP1 and ATPase-defective human SKD1 produce similar effects on endosome structure. COS7 cells were transiently transfected with plasmids encoding the indicated GFP-fusion proteins, fixed, and labeled with antibodies to the indicated proteins or lipid, plus nuclear dye Hoechst 33258. Transfected (arrowheads) and endogenous patterns (arrows) are indicated. (A) Cell were analyzed by phase-contrast and fluorescent microscopy. Note the GFP-positive, phase-contrast visible structures in the cytoplasm that are produced by both CHMP1 and SKD1(EQ) fusions. (B) The indicated antigens were visualized by indirect immunofluorescence microscopy. EEA1 (early endosome antigen 1), a marker for early endosomes (Mu et al., 1995); lysobisphosphatidic acid (LBPA), late endosomes (Kobayashi et al., 1998); and cationic-independent mannose-6-phosphate receptor (M6PR) present on both early and late endosomes.
