Proteomic screen with the proto-oncogene beta-catenin identifies interaction with Golgi coatomer complex I

Crystal Semaan; Beric R Henderson; Mark P Molloy

doi:10.1016/j.bbrep.2019.100662

Proteomic screen with the proto-oncogene beta-catenin identifies interaction with Golgi coatomer complex I

Biochem Biophys Rep. 2019 Jul 10:19:100662. doi: 10.1016/j.bbrep.2019.100662. eCollection 2019 Sep.

Authors

Crystal Semaan^{1

2}, Beric R Henderson³, Mark P Molloy^{1

4

5}

Affiliations

¹ Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, Australia.
² Gene and Stem Cell Therapy Program Centenary Institute, The University of Sydney, Camperdown, 2050, NSW, Australia.
³ Westmead Institute for Medical Research, University of Sydney, Australia.
⁴ Australian Proteome Analysis Facility, Macquarie University, Sydney, Australia.
⁵ Bowel Cancer and Biomarker Laboratory, Kolling Institute, The University of Sydney, Australia.

Abstract

Beta-catenin is well-known as a key effector of Wnt signalling and aberrant expression is associated with several human cancers. Stabilisation of and atypical subcellular localisation of beta-catenin, regulated in part through specific protein-protein interactions has been linked to cancer development, however the mechanisms behind these pathologies is yet to be fully elucidated. Affinity purification and mass spectrometry were used to identify potential β-catenin interacting proteins in SW480 colon cancer cells. Recombinant β-catenin constructs were used to co-isolate interacting proteins from stable isotope labelled cells followed by detection using mass spectrometry. Several known and new putative interactors were observed. In particular, we identified interaction with a set of coatomer complex I subunits implicated in retrograde transport at the Golgi, and confirmed endogenous interaction of β-catenin with coatomer subunit COPB using immunoprecipitation assays and immunofluorescence microscopy. These observations suggest a hitherto unrecognised role for β-catenin in the secretory pathway and warrant further functional studies to unravel its activity at this cellular location.

Keywords: COPB; Cancer; Golgi; Mass spectrometry; Protein interactions; β-catenin.