Protein-protein interaction techniques: dissect PCP signaling in Xenopus

The planar cell polarity (PCP) pathway is a β-catenin-independent branch of the Wnt signaling cascade. In vertebrate embryos PCP signaling regulates morphogenetic events including convergent extension (CE) movements during gastrualtion. Xenopus embryo has been established as an excellent model system to dissect PCP signaling in vertebrates because morphogenetic cell behaviors including CE can easily be monitored in vivo. Xenopus Paraxial protocadherin (xPAPC) is a transmembrane protein which serves as a link between patterning factors in the Spemann's organizer and regulators of the morphogenetic movements. xPAPC regulates morphogenesis in part by modulating cell adhesion and PCP signaling. Here two methods, GST pull-down assay and yeast two-hybrid assay, are described for the identification of xPAPC interacting proteins to elucidate the mechanism by which xPAPC regulates PCP signaling.