Coexpression and protein-protein complexing of DIX domains of human Dvl1 and Axin1 protein

The Dvl and Axin proteins, which are involved in the Wnt signaling pathway, each contain a conserved DIX domain in their sequences. The DIX domain mediates interaction between Dvl and Axin, which together play an important role in signal transduction. However, the extremely low production of DIX domain fragments in E. coli has prevented more widespread functional and structural studies. In this study, we demonstrate that the DIX domains of Dvl and Axin are expressed noticeably in a multi-cistronic system but not in a mono-cistronic system. Formation of the DIXDvl1-DIXAxin1 complex was investigated by affinity chromatography, SEC and crystallization studies. Unstable DIX domains were stabilized by complexing with counterpart DIX domains. The results of the preliminary crystallization and diffraction of the DIXDvl1-DIXAxin1 complex may prove useful for further crystallographic studies. [BMB reports 2010; 43(9): 609-613]