title: Modulation of the Hsp90 chaperone cycle by a stringent client protein.
abstract: Hsp90 is the most abundant molecular chaperone in the eukaryotic cell. One of the most stringent clients is the glucocorticoid receptor (GR), whose in vivo function strictly depends on the interaction with the Hsp90 machinery. However, the molecular mechanism of this interaction has been elusive. Here we have reconstituted the interaction of Hsp90 with hormone-bound GR using purified components. Our biochemical and structural analyses define the binding site for GR on Hsp90 and reveal that binding of GR modulates the conformational cycle of Hsp90. FRET experiments demonstrate that a partially closed form of the Hsp90 dimer is the preferred conformation for interaction. Consistent with this, the conformational cycle of Hsp90 is decelerated, and its ATPase activity decreases. Hsp90 cochaperones differentially affect formation of the Hsp90-GR complex, serving as control elements for cycle progression and revealing an intricate interplay of client and cochaperones as molecular modulators of the Hsp90 machine.
authors.affiliation: Center for Integrated Protein Science Munich, Department Chemie, Technische Universität München, 85478 Garching, Germany.
authors.forename: Oliver Robin
authors.initials: OR
authors.lastname: Lorenz
authors.affiliation: Center for Integrated Protein Science Munich, Department Chemie, Technische Universität München, 85478 Garching, Germany; Institute of Structural Biology, Helmholtz Zentrum München, 85764 Neuherberg, Germany.
authors.forename: Lee
authors.initials: L
authors.lastname: Freiburger
authors.affiliation: Center for Integrated Protein Science Munich, Department Chemie, Technische Universität München, 85478 Garching, Germany.
authors.forename: Daniel Andreas
authors.initials: DA
authors.lastname: Rutz
authors.affiliation: Center for Integrated Protein Science Munich, Department Chemie, Technische Universität München, 85478 Garching, Germany.
authors.forename: Maike
authors.initials: M
authors.lastname: Krause
authors.affiliation: Center for Integrated Protein Science Munich, Department Chemie, Technische Universität München, 85478 Garching, Germany.
authors.forename: Bettina Karolina
authors.initials: BK
authors.lastname: Zierer
authors.affiliation: Centro Nacional de Biotecnología (CNB-CSIC), Darwin 3, 28049 Madrid, Spain.
authors.forename: Sara
authors.initials: S
authors.lastname: Alvira
authors.affiliation: Centro Nacional de Biotecnología (CNB-CSIC), Darwin 3, 28049 Madrid, Spain.
authors.forename: Jorge
authors.initials: J
authors.lastname: Cuéllar
authors.affiliation: Centro Nacional de Biotecnología (CNB-CSIC), Darwin 3, 28049 Madrid, Spain.
authors.forename: José María
authors.initials: JM
authors.lastname: Valpuesta
authors.affiliation: Center for Integrated Protein Science Munich, Department Chemie, Technische Universität München, 85478 Garching, Germany; Institute of Structural Biology, Helmholtz Zentrum München, 85764 Neuherberg, Germany. Electronic address: t.madl@tum.de.
authors.forename: Tobias
authors.initials: T
authors.lastname: Madl
authors.affiliation: Center for Integrated Protein Science Munich, Department Chemie, Technische Universität München, 85478 Garching, Germany; Institute of Structural Biology, Helmholtz Zentrum München, 85764 Neuherberg, Germany. Electronic address: michael.sattler@tum.de.
authors.forename: Michael
authors.initials: M
authors.lastname: Sattler
authors.affiliation: Center for Integrated Protein Science Munich, Department Chemie, Technische Universität München, 85478 Garching, Germany. Electronic address: johannes.buchner@tum.de.
authors.forename: Johannes
authors.initials: J
authors.lastname: Buchner
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D045744:Cell Line, Tumor; D015966:Gene Expression Regulation, Fungal; D018841:HSP90 Heat-Shock Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008958:Models, Molecular; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D055503:Protein Multimerization; D017433:Protein Structure, Secondary; D011965:Receptors, Glucocorticoid / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D018841:HSP90 Heat-Shock Proteins; D011965:Receptors, Glucocorticoid; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D000251:Adenosine Triphosphatases