title: Identification of small-molecule antagonists that inhibit an activator: coactivator interaction.
abstract: Phosphorylation of the cAMP response element binding protein (CREB) at Ser-133 in response to hormonal stimuli triggers cellular gene expression via the recruitment of the histone acetylase coactivator paralogs CREB binding protein (CBP) and p300 to the promoter. The NMR structure of the CREB:CBP complex, using relevant interaction domains called KID and KIX, respectively, reveals a shallow hydrophobic groove on the surface of KIX that accommodates an amphipathic helix in phospho (Ser-133) KID. Using an NMR-based screening approach on a preselected small-molecule library, we identified several compounds that bind to different surfaces on KIX. One of these, KG-501 (2-naphthol-AS-E-phosphate), targeted a surface distal to the CREB binding groove that includes Arg-600, a residue that is required for the CREB:CBP interaction. When added to live cells, KG-501 disrupted the CREB: CBP complex and attenuated target gene induction in response to cAMP agonist. These results demonstrate the ability of small molecules to interfere with second-messenger signaling cascades by inhibiting specific protein-protein interactions in the nucleus.
authors.affiliation: Department of Peptide Biology and Regulatory Biology Laboratories, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037-1002, USA.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Best
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Amezcua
authors.forename: Bernhard
authors.initials: B
authors.lastname: Mayr
authors.forename: Lawrence
authors.initials: L
authors.lastname: Flechner
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Murawsky
authors.forename: Beverly
authors.initials: B
authors.lastname: Emerson
authors.forename: Tsaffrir
authors.initials: T
authors.lastname: Zor
authors.forename: Kevin H
authors.initials: KH
authors.lastname: Gardner
authors.forename: Marc
authors.initials: M
authors.lastname: Montminy
mesh_terms: D050882:CREB-Binding Protein; D002460:Cell Line; D017362:Cyclic AMP Response Element-Binding Protein / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D008958:Models, Molecular; D009284:Naphthols / Q000737:chemistry / Q000494:pharmacology*; D019906:Nuclear Magnetic Resonance, Biomolecular; D009687:Nuclear Proteins / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism*; D010755:Organophosphates / Q000737:chemistry / Q000494:pharmacology*; D010768:Phosphoserine / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D011487:Protein Conformation; D015398:Signal Transduction / Q000187:drug effects; D015534:Trans-Activators / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism*
chemical_list: D017362:Cyclic AMP Response Element-Binding Protein; D009284:Naphthols; D009687:Nuclear Proteins; D010755:Organophosphates; D015534:Trans-Activators; C495860:naphthol AS-E phosphate; D010768:Phosphoserine; C004368:pamoic acid; D050882:CREB-Binding Protein; C494363:CREBBP protein, human