FIG 3.

VAMP3 and VAMP4 interact with multiple chlamydial Inc proteins by the BACTH analyses. VAMP3 and VAMP4 were screened in triplicate against a library of 30 chlamydial Inc proteins using the BACTH system, followed by quantitative β-galactosidase assays. Graphed results are representative of positive interactions that were consistent across all three biological replicates between VAMP3 and indicated Inc proteins (A) and VAMP4 and indicated Inc proteins (B). Data are represented as arbitrary units from β-galactosidase assays. The dashed line indicates a cutoff for positive interactions, as determined by a 5-fold increase in activity compared to that of the negative controls (EV [empty vector/pUT18C] and IncE), which is an established threshold for positive interactions (47, 50). The positive control, syntaxin 6 (Stx6), is a known eukaryotic SNARE binding partner for both VAMP3 and VAMP4 (78, 79). The data were graphed with GraphPad Prism and are represented as the means ± SEM. Complete data sets can be found in Fig. S3 for VAMP3 and Fig. S4 for VAMP4. (C) Venn diagram of shared or specific interactions between VAMP3 and VAMP4 with Inc proteins. The Venn diagram was made using Venny v2.1 (80).