Homer condensates orchestrate YAP-Wnt signaling crosstalk downstream of the Crumbs polarity complex

The Hippo pathway controls cell growth, proliferation and differentiation, and is frequently deregulated in cancers. YAP, the central transcriptional co-activator of the Hippo pathway, is suppressed by the canonical Hippo kinases and several poorly characterized non-canonical mechanisms. YAP also interacts with the Wnt/β-catenin signaling pathway, yet how this crosstalk is regulated is not well understood. Here we show that Homer scaffolding proteins act downstream of the Crumbs polarity complex to promote YAP/TEAD and canonical Wnt/β-catenin signaling in epithelial and cancer cells. We demonstrate that Homers via their EVH1 domains interact directly with the Crumbs complex protein PatJ as well as with the NDR kinase scaffolding protein Furry-like (FRYL). FRYL acts antagonistically to Homers in controlling YAP/TEAD signaling but cooperates with Homers to promote Wnt/β-catenin signaling output. Intriguingly, live and fixed cell imaging, Fluorescence Recovery After Photobleaching, and electron microscopy revealed that all three Homer proteins form cytoplasmic biomolecular condensates with unique ultrastructural and material properties. These condensates effectively sequestered PatJ, FRYL, NDR, YAP, and β-catenin, with PatJ and FRYL exerting opposing effects on the condensate’s properties. Finally, in colorectal cancer cells, Homers enhance YAP and Wnt signaling and promote cell migration, suggesting a tumor-promoting function for Homers. Overall, our findings suggest that Homers coordinate YAP-Wnt signaling crosstalk through cytoplasmic phase separation, linking polarity cues to transcriptional regulation.