An arrow for wingless to take-off.

The Wnt family of secreted glycoproteins is involved in the regulation of diverse developmental processes. The classical Wnt/beta-catenin pathway has been thoroughly investigated resulting in the identification of a plethora of components involved in the activation of beta-catenin target genes. Moreover, two additional Wnt-triggered pathways have been identified. These various signalling cascades require at least one component that confers signalling specificity. This function is fulfilled at least in part by the Wnt receptor Frizzled. The recent identification of a potential Frizzled co-receptor, an LDL-receptor-related-protein (LRP), sheds more light on Wnt-signal transduction specificity and promises more exciting revelations.