title: Identification of a Wnt-induced protein complex by affinity proteomics using an antibody that recognizes a sub-population of β-catenin.
abstract: β-catenin is a signaling protein with diverse functions in cell adhesion and Wnt signaling. Although β-catenin has been shown to participate in many protein-protein interactions, it is not clear which combinations of β-catenin-interacting proteins form discrete complexes. We have generated a novel antibody, termed 4B3, which recognizes only a small subset of total cellular β-catenin. Affinity proteomics using 4B3, in combination with subcellular fractionation, has allowed us to define a discrete trimeric complex of β-catenin, α-catenin and the tumor suppressor APC, which forms in the cytoplasm in response to Wnt signaling. Depletion of the limiting component of this complex, APC, implicates the complex in mediating Wnt-induced changes in cell-cell adhesion. APC is also essential for N-terminal phosphorylation of β-catenin within this complex. Each component of β-catenin/APC/α-catenin complex co-exists in other protein complexes, thus use of a selective antibody for affinity proteomics has allowed us to go beyond the generation of a list of potential β-catenin-interacting proteins, and define when and where a specific complex forms.
authors.affiliation: The Ludwig Institute for Cancer Research, Melbourne Hospital, Parkville, Australia.
authors.forename: Meredith J
authors.initials: MJ
authors.lastname: Layton
authors.forename: Maree C
authors.initials: MC
authors.lastname: Faux
authors.forename: Nicole L
authors.initials: NL
authors.lastname: Church
authors.forename: Bruno
authors.initials: B
authors.lastname: Catimel
authors.forename: Nadia J
authors.initials: NJ
authors.lastname: Kershaw
authors.forename: Eugene A
authors.initials: EA
authors.lastname: Kapp
authors.forename: Cameron
authors.initials: C
authors.lastname: Nowell
authors.forename: Janine L
authors.initials: JL
authors.lastname: Coates
authors.forename: Antony W
authors.initials: AW
authors.lastname: Burgess
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Simpson
mesh_terms: D025601:Adenomatous Polyposis Coli Protein / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis*; D002448:Cell Adhesion; D002458:Cell Fractionation; D002460:Cell Line; D002846:Chromatography, Affinity; D002853:Chromatography, Liquid; D006801:Humans; D051379:Mice; D010766:Phosphorylation; D011485:Protein Binding; D055503:Protein Multimerization; D040901:Proteomics / Q000379:methods; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D061987:Sf9 Cells / Q000166:cytology / Q000378:metabolism; D018411:Spodoptera; D053719:Tandem Mass Spectrometry; D060449:Wnt Signaling Pathway; D051178:alpha Catenin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051176:beta Catenin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: C555337:APC protein, human; D025601:Adenomatous Polyposis Coli Protein; D000911:Antibodies, Monoclonal; C495270:CTNNB1 protein, human; D011994:Recombinant Proteins; D051178:alpha Catenin; D051176:beta Catenin