Fig. 7: Oncogenic APC enhances macromolecular interactions within Wnt receptor nanoscale signaling platforms.

For in vitro FLIM-FRET experiments, cells co-expressing EGFP- and mCherry-tagged A Fzd7 or B LRP6 or C EGFP-tagged LRP6 and mCherry-tagged Fzd7 were used to perform homo- and hetero-clustering FLIM-FRET analyses, respectively. To examine the effect of oncogenic APC on the interactions between Dvl1 and Wnt receptors, cells co-expressing EGFP-tagged D Fzd7 or E LRP6 and mCherry-tagged Dvl1 were used to perform FLIM-FRET. To examine the effect of oncogenic APC on plasma membrane Wnt receptor localization, cells co-expressing EGFP-tagged F Fzd7 or G LRP6 and tH-RFP were used to perform FLIM-FRET analyses. For FLIM-FRET experiments, YAMC, IMCE, and IMCE βcat cells were pre-treated with mevastatin (5 µM, 24 h), MβCD (10 mM, 30 min), or phenylarsine oxide (PAO) (20 µM, 30 min) and washed, as indicated. Subsequently, cells were incubated with Wnt3a-conditioned media or control media without Wnt3a for 30 min, washed, fixed, and imaged. The apparent FRET efficiency was calculated from FLIM data averaged per FOV (mean ± SD, from n = 10–15 FOVs containing 3–5 cells each were examined per condition, exact n value is shown in each graph). For all experiments, statistical significance was determined by two-way ANOVA and post Tukey’s multiple comparison test. Different letters indicate significant differences between WT APC (control) and mutant APC/treatment groups (experimental) (P < 0.05). Source data are provided as a Source data file.