Destruction complex function in the Wnt signaling pathway of Drosophila requires multiple interactions between Adenomatous polyposis coli 2 and Armadillo.

The tumor suppressor Adenomatous polyposis coli (APC) negatively regulates Wnt signaling through its activity in the destruction complex. APC binds directly to the main effector of the pathway, β-catenin (βcat, Drosophila Armadillo), and helps to target it for degradation. In vitro studies demonstrated that a nonphosphorylated 20-amino-acid repeat (20R) of APC binds to βcat through the N-terminal extended region of a 20R.

Cortical localization of APC2 plays a role in actin organization but not in Wnt signaling in Drosophila.

The tumor suppressor Adenomatous polyposis coli (APC) has roles in both Wnt signaling and in actin and microtubule organization. Within the cell, APC proteins have been reported to localize in the cytoplasm, at the cell cortex and in the nucleus. How these localizations relate to the functions of the protein is an aspect of APC biology that is poorly understood.