FIG. 3.

Inactivating point mutations do not disrupt multimer formation. HeLa cells were infected with vT7 and were then cotransfected with plasmids expressing the indicated proteins as described in Materials and Methods. After 18 to 24 h, the fluorescence emission of the transfected cells was analyzed by fluorescence microscopy, and FRET images were collected and analyzed as described for Fig. 1. The data were manipulated as described in the text. Values represent the average of at least 12 independent cells and 3 independent experiments. For triple-transfected cells expressing VacA (P9A)-CFP, VacA (P9A)-YFP, and p37, P < 0.001 compared to that for cotransfected cells expressing VacA (P9A)-CFP and VacA (P9A)-YFP.