Fig. 2. A screen for TBC domain proteins that alter ERGIC structure. (A-C) HeLa cells were transfected with the GFP-tagged wild-type and catalytically inactive point mutant TBC-domain proteins listed in the figure. After 24 hours they were fixed, and then stained with antibodies to ERGIC53. (A) The number of cells displaying a fragmented ERGIC was then counted (n>100 per condition), expressed as a percentage, and then plotted as a bar graph: grey bars, wild-type GAPs; open bars, inactive mutants. (B) Cells stained for the expressed wild-type (WT) TBC1D20 and RN-tre, and ERGIC53 are shown. (C) Cells stained for the expressed catalytically inactive mutant (RA) TBC1D20 R105A and RN-tre R150A and ERGIC53 are shown. Bars, 10 µm, in all panels.