FIG 4.
ElpA triggers disruption of ER structure. Full-length GFP-ElpA, GFP-ElpA1–343, and GFP-ElpA341–418 were individually expressed in HeLa cells (green), and cells were processed at 18 h posttransfection for fluorescence microscopy. The ER was detected using antibody directed against calnexin (red) and DAPI-stained DNA (blue). Bar, 10 μm. The graph indicates the percentage of transfected cells containing disrupted ER structure under each condition. Error bars represent the standard deviations from the means, and data were collected from at least 100 cells/condition from experiments performed in triplicate. *, P < 0.0001 by Student's t test when truncations and full-length GFP-ElpA are compared. Ectopic expression of GFP-ElpA alters ER structure, leading to accumulation of calnexin-rich ElpA-containing compartments in the cytoplasm. In contrast, most cells expressing GFP-ElpA1–343 or GFP-ElpA341–418 contain a normal ER structure.