Mammalian homologs of the Drosophila dishevelled (Dsh) gene have been identified, including Dvl-1, Dvl-2 and Dvl-3. The mammalian dishevelled proteins contain three homologous domains, two of which are unrelated to any other known protein. The third region is homologous to the discs-large homology domain of Drosophila discs-large-1, a tumor suppressor protein. Like their Drosophila counterpart, the dishevelled proteins are thought to be involved in embryogenesis. Overexpression of Dvl-1 has been shown to inhibit the phosphorylation of tau by GSK-3? This finding may prove to be important in Alzheimer studies, which have shown that tau is hyperphosphorylated. In Drosophila, Dsh is a component of the frizzled signaling pathway. Both mammalian dishevelled and frizzled proteins are components of the Wnt signalling pathway.