NIH3T3 fibroblasts stably transduced with mCherry-tagged GBP2 (wildtype and mutants, red) and unprimed cells were infected with B. thailandensis (GFP+). (a-c) Cells were fixed at 12 h post-infection, stained for F-actin (white), and images were collected for GBP2 localization and F-actin tail quantification. NIH3T3 fibroblasts pre-stained with CellTrace Far Red or CellTrace Violet and seeded overnight at a 1:1 ratio (d) were fixed at 24 h post-infection and imaged for cell fusion and (e) had fusion quantified by colocalization of the two CellTrace signals. Dotted white line outlines the boundary of large MNGC formed during infection. Images are representative of at least ten images collected for quantification. White scale bars indicate 20 μm. Significance was determined by one-way ANOVA with the Holm-Sidak multiple comparison test, *P < 0.05, ****P < 0.0001 (b, c, e).