Identifying mechanisms regulating Wnt signaling during postembryonic development

Proper regulation of the Wingless (Wg)/Wnt pathway is essential for development; inappropriate activation of the pathway occurs in many human cancers. Wg signaling stabilizes the effector, Armadillo (Arm) and in its absence Arm is phosphorylated, ubiquitinated, and then degraded. In this work, we take a closer look at Arm regulation. First we investigated the difference in Arm accumulation in APC, a member of the destruction complex, mutants. We find that while protein levels of Arm are the same, mRNA levels differ between embryos and larvae. Second, published data suggests that the SCF complex is responsible for Arm ubiquitination. The canonical SCF complex is known to contain five parts, including a RING domain protein of the Roc1/Rbx1 family. However, some data has called into question the exactly which Roc protein is part of the complex. Our data suggests that neither Roc1b nor Roc2 are solely responsible for Arm degradation