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Fig. 2. Reversal of SARA-mediated endosome enlargement by Rab5S34N overexpression.
MDCK cells cotransfected with GFP-SARA (green) with Rab5Q79L (A-C) or Rab5S34N
(D-F) were fixed for Rab5 immunostaining (red). Rab5 transfected cells can be
easily distinguished from the neighboring untransfected cells based on their
higher level of Rab5 immunolabeling. Because the photographic exposure was
chosen to highlight the transfected cells, the endogenous Rab5 labeling is
negligible in these figures. (A-C) Rab5Q79L labeling is extensively
colocalized with SARA on enlarged early endosomal membranes. (D-F) In contrast
to the cells singly transfected with GFP-SARA, in which green fluorescence is
observed on enlarged endosomal membranes (arrowheads), GFP signals are
distributed diffusely in the cytosol and on small puncta in the cells
co-transfected with GFA-SARA and Rab5S34N (arrow). Bar, 10 µm.