The canonical Wnt/β-catenin and Wnt/Ca2+ pathways play vital, but distinct, roles in vertebrate development. The first patterns the anteroposterior (AP) axis in early development; the second, together with orthologues of the Drosophila planar cell polarity (PCP) pathway,controls gastrulation cell movements. Both act through Dishevelled (Dvl). On p. , Waxman and colleagues describe how Dapper1 (Dpr1) and Dapper2 (Dpr2), zebrafish proteins that interact with Dvl, help to separate Wnt signalling pathways at Dvl. Loss-of function experiments show that endogenous Dpr1, but not Dpr2, is required for proper dorsoventral and AP patterning in zebrafish embryos with reduced Wnt8 activity, suggesting that Dpr1 enhances Wnt/β-catenin signalling in early development. Conversely, Dpr2, but not Dpr1, is required for proper gastrulation movements in embryos hypomorphic for Wnt11, indicating that Dpr2 enhances the Wnt/Ca2+-PCP pathway. These and other experiments indicate that Dpr1 and Dpr2 act in distinct Wnt-dependent developmental processes.
