Systematic peptide array-based delineation of the differential beta-catenin interaction with Tcf4, E-cadherin, and adenomatous polyposis coli.
Nuclear accumulation of the complex between beta-catenin and proteins of the T-cell factor (Tcf) family is a hallmark of many cancers. Targeting this interaction for drug development is complicated by the fact that E-cadherin and adenomatous polyposis coli (APC) bind to overlapping sites on beta-catenin. Inhibiting their interactions might actually promote tumor growth. To identify selective beta-catenin binding hot spots of Tcf4, E-cadherin, and APC, array technology with peptides of up to 53 amino acids length was used. Interactions were monitored by a quantitative fluorescent readout, which was shown to represent a monitor of true equilibrium binding constants. We identified minimal binding motifs in the beta-catenin ligands and showed that most of the 15-mer and 20-mer repeats of APC did not interact, at least when non-phosphorylated, and defined a consensus binding motif also present in APC. We confirmed previously found hot spots and identified new ones. The method allowed us to locate a hydrophobic pocket that was relevant for the Tcf, but not the E-cadherin interaction, and would thus constitute an ideal drug target site.
Gail
Robert
R
Abteilung strukturelle Biologie, Max-Planck-Institut für molekulare Physiologie, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany.
Frank
Ronald
R
Wittinghofer
Alfred
A
D000818:Animals; D001665:Binding Sites; D015820:Cadherins / Q000737:chemistry / Q000378:metabolism*; D020650:Combinatorial Chemistry Techniques; D003598:Cytoskeletal Proteins / Q000737:chemistry / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D016503:Drug Delivery Systems; D006801:Humans; D008024:Ligands; D051379:Mice; D008958:Models, Molecular; D010455:Peptides / Q000138:chemical synthesis* / Q000378:metabolism; D040081:Protein Array Analysis; D025941:Protein Interaction Mapping / Q000379:methods; D051820:TCF Transcription Factors; D015534:Trans-Activators / Q000737:chemistry / Q000378:metabolism*; D058118:Transcription Factor 7-Like 2 Protein; D014157:Transcription Factors / Q000737:chemistry / Q000378:metabolism*; D051176:beta Catenin
C495270:CTNNB1 protein, human; C495267:CTNNB1 protein, mouse; D015820:Cadherins; D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins; D008024:Ligands; D010455:Peptides; D051820:TCF Transcription Factors; C544894:TCF7L2 protein, human; C544895:Tcf7l2 protein, mouse; D015534:Trans-Activators; D058118:Transcription Factor 7-Like 2 Protein; D014157:Transcription Factors; D051176:beta Catenin