Multivalent tumor suppressor adenomatous polyposis coli promotes Axin biomolecular condensate formation and efficient β-catenin degradation
Tie‐Mei Li, Jing Ren, Dylan Husmann, John P. Coan, Or Gozani, Katrin F. Chua
Abstract
The tumor suppressor adenomatous polyposis coli (APC) is frequently mutated in colorectal cancers. APC and Axin are core components of a destruction complex that scaffolds GSK3β and CK1 to earmark β-catenin for proteosomal degradation. Disruption of APC results in pathologic stabilization of β-catenin and oncogenesis. However, the molecular mechanism by which APC promotes β-catenin degradation is unclear. Here, we find that the intrinsically disordered region (IDR) of APC, which contains multiple β-catenin and Axin interacting sites, undergoes liquid-liquid phase separation (LLPS) in vitro. Expression of the APC IDR in colorectal cells promotes Axin puncta formation and β-catenin degradation. Our results support the model that multivalent interactions between APC and Axin drives the β-catenin destruction complex to form biomolecular condensates in cells, which concentrate key components to achieve high efficient degradation of β-catenin.