Wnt signalling: What The X@# is WTX?

EMBO J 30 8, 1433–1443 (2011); published online February 08 2011 In this issue of The EMBO Journal, Tanneberger et al demonstrate that Amer1/WTX, a tumour suppressor protein previously known for promoting β-catenin degradation and thus antagonizing Wnt signalling, is also required for LRP6 receptor phosphorylation and therefore activation of Wnt signalling. Amer1/WTX is recruited by PtdIns(4,5)P2 to the plasma membrane, and in turn recruits the Axin–GSK3 complex and CK1γ to phosphorylate LRP6. While dichotomic players like Amer1/WTX are common in Wnt signalling, these new findings add more intrigues to this enigmatic protein and pathway.