The thioredoxin-related redox-regulating protein nucleoredoxin inhibits Wnt-β-catenin signalling through dishevelled

Dishevelled (Dvl) transduces signals from the Wnt receptor, Frizzled, to downstream components, leading to the stabilization of beta-catenin and subsequent activation of the transcription factor T cell factor (TCF) and/or lymphoid enchancer factor (LEF)(1-3). However, the mechanism of Dvl action remains unclear. Here, we report that nucleoredoxin (NRX)(4), a thioredoxin (TRX) family protein, interacts with Dvl. Overexpression of NRX selectively suppresses the Wnt-beta-catenin pathway and ablation of NRX by RNA-interference (RNAi) results in activation of TCF, accelerated cell proliferation and enhancement of oncogenicity through cooperation with mitogen-activated extracellular signal regulated kinase kinase (MEK) or Ras. We find that cells respond to H2O2 stimulation by activating TCF. Redox-dependent activation of the Wnt-beta-catenin pathway occurs independently of extracellular Wnts and is impaired by RNAi of NRX. In addition, association between Dvl and NRX is inhibited by H2O2 treatment. These data suggest a relationship between the Wnt-beta-catenin pathway and redox signalling through redox-sensitive association of NRX with Dvl.