title: Binding-pocket and lid-region substitutions render human STING sensitive to the species-specific drug DMXAA.
abstract: The drug DMXAA (5,6-dimethylxanthenone-4-acetic acid) showed therapeutic promise against solid tumors in mouse models but subsequently failed in human clinical trials. DMXAA was later discovered to activate mouse, but not human, STING, an adaptor protein in the cyclic dinucleotide cGAMP-mediated signaling pathway, inducing type I interferon expression. To facilitate the development of compounds that target human STING, we combined structural, biophysical, and cellular assays to study mouse and human chimeric proteins and their interaction with DMXAA. We identified a single substitution (G230I) that enables a DMXAA-induced conformational transition of hSTING from an inactive "open" to an active "closed" state. We also identified a substitution within the binding pocket (Q266I) that cooperates with G230I and the previously identified S162A binding-pocket point substitution, rendering hSTING highly sensitive to DMXAA. These findings should facilitate the reciprocal engineering of DMXAA analogs that bind and stimulate wild-type hSTING and their exploitation for vaccine-adjuvant and anticancer drug development.
authors.affiliation: Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA.
authors.forename: Pu
authors.initials: P
authors.lastname: Gao
authors.affiliation: Institute of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, University of Bonn, Bonn 53127, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Zillinger
authors.affiliation: Dermatology Service, Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA.
authors.forename: Weiyi
authors.initials: W
authors.lastname: Wang
authors.affiliation: Laboratory of RNA Molecular Biology, Howard Hughes Medical Institute, Rockefeller University, New York, NY 10065, USA.
authors.forename: Manuel
authors.initials: M
authors.lastname: Ascano
authors.affiliation: Dermatology Service, Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA.
authors.forename: Peihong
authors.initials: P
authors.lastname: Dai
authors.affiliation: Institute of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, University of Bonn, Bonn 53127, Germany.
authors.forename: Gunther
authors.initials: G
authors.lastname: Hartmann
authors.affiliation: Laboratory of RNA Molecular Biology, Howard Hughes Medical Institute, Rockefeller University, New York, NY 10065, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Tuschl
authors.affiliation: Dermatology Service, Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA.
authors.forename: Liang
authors.initials: L
authors.lastname: Deng
authors.affiliation: Institute of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, University of Bonn, Bonn 53127, Germany. Electronic address: winfried.barchet@ukb.uni-bonn.de.
authors.forename: Winfried
authors.initials: W
authors.lastname: Barchet
authors.affiliation: Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA. Electronic address: pateld@mskcc.org.
authors.forename: Dinshaw J
authors.initials: DJ
authors.lastname: Patel
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry / Q000378:metabolism / Q000627:therapeutic use; D001665:Binding Sites; D018925:Chemokines / Q000378:metabolism; D018360:Crystallography, X-Ray; D057809:HEK293 Cells; D006801:Humans; D007370:Interferon Type I / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D056004:Molecular Dynamics Simulation; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009369:Neoplasms / Q000188:drug therapy; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D016415:Sequence Alignment; D044004:Xanthones / Q000737:chemistry / Q000378:metabolism* / Q000627:therapeutic use; D000099197:STING Protein
chemical_list: D000970:Antineoplastic Agents; D018925:Chemokines; D007370:Interferon Type I; D008565:Membrane Proteins; D011993:Recombinant Fusion Proteins; D044004:Xanthones; C532857:STING1 protein, human; D000099197:STING Protein; C066668:vadimezan