Structural determinants of Dishevelled isoform selectivity at the Wnt receptor Frizzled-7

Activation of the Wnt receptor Frizzled-7 has been shown to regulate epithelial renewal and patterning, making Frizzled-7 an important target in the promotion of tissue repair and regeneration. Although the receptor signals through cytoplasmic Dishevelled adaptors, more work is necessary to understand differences in adaptor coupling and their relation to morphogenetic outcomes. To develop a molecular understanding of the factors governing adaptor coupling and activation, we performed structure–activity relationship studies of Frizzled-7 with distinct Dishevelled isoforms. Through a combination of in vitro organoid assays, we identified a potent partial agonist—an engineered Wnt surrogate—that selectively engages a single Dishevelled isoform. We further investigated the differences in adaptor engagement at Frizzled-7 with cryo–electron microscopy, determining structures of Frizzled-7 bound to distinct ligands and Dishevelled isoforms. Combined with subsequent structure-guided mutagenesis and signaling readouts, our studies uncover both orthosteric and allosteric determinants of agonist-specific stimulation of distinct intracellular transducers, providing a framework for precision control of Wnt-dependent regenerative responses.