Proximity interactomics identifies RAI14, EPHA2 and PHACTR4 as essential components of Wnt/planar cell polarity pathway in vertebrates

Wnt/planar cell polarity (Wnt/PCP) pathway is an evolutionarily conserved signaling cascade playing an inevitable role in cell biology. Deregulation of Wnt/PCP leads to severe developmental defects or cancer progression. Here, we applied proximity-dependent biotinylation (BioID) to capture the intracellular interactome of key Wnt/PCP components: transmembrane ROR1, ROR2 and VANGL2, and cytoplasmic DVL3 and PRICKLE1. Mapping of individual preys across the baits and subcellular compartments identified a group of 30 proteins that we tested by loss-of-function in zebrafish. Among those rai14, epha2 and phactr4 were essential for several Wnt/PCP-dependent processes such as zebrafish convergent extension, orientation of lateral organ cells, or migration of melanoma cells. Mechanistically, RAI14, EPHA2 and PHACTR4 connect the receptor complex to effector actomyosin. In summary, this study identified novel essential components of vertebrate WNT/PCP pathway and provides a detailed characterization of PCP complex composition that can serve as comprehensive resource for further analysis of Wnt/PCP function.