arrow encodes an LDL-receptor-related protein essential for Wingless signalling (vol 407, pg 527, 2000)

The Wnt family of secreted molecules functions in cell-fate determination a nd morphogenesis during development in both vertebrates and invertebrates ( reviewed in ref. 1). Drosophila Wingless is a founding member of this famil y, and many components of its signal transduction cascade have been identif ied, including the Frizzled class of receptor. But the mechanism by which t he Wingless signal is received and transduced across the membrane is not co mpletely understood. Here we describe a gene that is necessary for all Wing less signalling events in Drosophila. We show that arrow gene function is e ssential in cells receiving Wingless input and that it acts upstream of Dis hevelled. arrow encodes a single-pass transmembrane protein, indicating tha t it may be part of a receptor complex with Frizzled class proteins. Arrow is a low-density lipoprotein (LDL)receptor-related protein (LRP), strikingl y homologous to murine and human LRP5 and LRP6. Thus, our data suggests a n ew and conserved function for this LRP subfamily in Wingless/Wnt signal rec eption.