title: Structural basis of PROTAC cooperative recognition for selective protein degradation.
abstract: Inducing macromolecular interactions with small molecules to activate cellular signaling is a challenging goal. PROTACs (proteolysis-targeting chimeras) are bifunctional molecules that recruit a target protein in proximity to an E3 ubiquitin ligase to trigger protein degradation. Structural elucidation of the key ternary ligase-PROTAC-target species and its impact on target degradation selectivity remain elusive. We solved the crystal structure of Brd4 degrader MZ1 in complex with human VHL and the Brd4 bromodomain (Brd4BD2). The ligand folds into itself to allow formation of specific intermolecular interactions in the ternary complex. Isothermal titration calorimetry studies, supported by surface mutagenesis and proximity assays, are consistent with pronounced cooperative formation of ternary complexes with Brd4BD2. Structure-based-designed compound AT1 exhibits highly selective depletion of Brd4 in cells. Our results elucidate how PROTAC-induced de novo contacts dictate preferential recruitment of a target protein into a stable and cooperative complex with an E3 ligase for selective degradation.
authors.affiliation: Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, Scotland, UK.
authors.forename: Morgan S
authors.initials: MS
authors.lastname: Gadd
authors.affiliation: Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, Scotland, UK.
authors.forename: Andrea
authors.initials: A
authors.lastname: Testa
authors.affiliation: Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, Scotland, UK.
authors.forename: Xavier
authors.initials: X
authors.lastname: Lucas
authors.affiliation: Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, Scotland, UK.
authors.forename: Kwok-Ho
authors.initials: KH
authors.lastname: Chan
authors.affiliation: Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, Scotland, UK.
authors.forename: Wenzhang
authors.initials: W
authors.lastname: Chen
authors.affiliation: Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, Scotland, UK.
authors.forename: Douglas J
authors.initials: DJ
authors.lastname: Lamont
authors.affiliation: Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, Scotland, UK.
authors.forename: Michael
authors.initials: M
authors.lastname: Zengerle
authors.affiliation: Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, Scotland, UK.
authors.forename: Alessio
authors.initials: A
authors.lastname: Ciulli
mesh_terms: D000595:Amino Acid Sequence; D018797:Cell Cycle Proteins; D018360:Crystallography, X-Ray; D004151:Dipeptides / Q000737:chemistry / Q000494:pharmacology; D000075065:Elongin; D006575:Heterocyclic Compounds, 3-Ring / Q000737:chemistry / Q000494:pharmacology; D006801:Humans; D008958:Models, Molecular; D046912:Multiprotein Complexes / Q000737:chemistry* / Q000378:metabolism*; D009687:Nuclear Proteins / Q000737:chemistry* / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D059748:Proteolysis / Q000187:drug effects*; D054852:Small Molecule Libraries / Q000737:chemistry / Q000494:pharmacology*; D013329:Structure-Activity Relationship; D013816:Thermodynamics; D014157:Transcription Factors / Q000737:chemistry* / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism*; D051794:Von Hippel-Lindau Tumor Suppressor Protein / Q000737:chemistry / Q000378:metabolism; D000092468:Bromodomain Containing Proteins
chemical_list: D018797:Cell Cycle Proteins; D004151:Dipeptides; D000075065:Elongin; D006575:Heterocyclic Compounds, 3-Ring; D046912:Multiprotein Complexes; D009687:Nuclear Proteins; D054852:Small Molecule Libraries; D014157:Transcription Factors; D044767:Ubiquitin-Protein Ligases; D051794:Von Hippel-Lindau Tumor Suppressor Protein; C000617637:AT1 compound; C441289:BRD4 protein, human; D000092468:Bromodomain Containing Proteins; C000617636:MZ1 compound; C497446:VHL protein, human