title: Structural characterization of the substrate transfer mechanism in Hsp70/Hsp90 folding machinery mediated by Hop.
abstract: In eukarya, chaperones Hsp70 and Hsp90 act coordinately in the folding and maturation of a range of key proteins with the help of several co-chaperones, especially Hop. Although biochemical data define the Hop-mediated Hsp70-Hsp90 substrate transfer mechanism, the intrinsic flexibility of these proteins and the dynamic nature of their complexes have limited the structural studies of this mechanism. Here we generate several complexes in the Hsp70/Hsp90 folding pathway (Hsp90:Hop, Hsp90:Hop:Hsp70 and Hsp90:Hop:Hsp70 with a fragment of the client protein glucocorticoid receptor (GR-LBD)), and determine their 3D structure using electron microscopy techniques. Our results show that one Hop molecule binds to one side of the Hsp90 dimer in both extended and compact conformations, through Hop domain rearrangement that take place when Hsp70 or Hsp70:GR-LBD bind to Hsp90:Hop. The compact conformation of the Hsp90:Hop:Hsp70:GR-LBD complex shows that GR-LBD binds to the side of the Hsp90 dimer opposite the Hop attachment site.
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: Center for Integrated Protein Science (CIPSM) at the Department Chemie, Technische Universität München, 85747 Garching, Germany.
authors.forename: Alina
authors.initials: A
authors.lastname: Röhl
authors.affiliation: 1] Department of Life Science, Faculty and Graduate School of Engineering and Resource Science, Akita University, Akita 010-8502, Japan [2] Department of Microbiology, Sapporo Medical University School of Medicine, Sapporo 060-8556, Japan.
authors.forename: Soh
authors.initials: S
authors.lastname: Yamamoto
authors.affiliation: Department of Life Science, Faculty and Graduate School of Engineering and Resource Science, Akita University, Akita 010-8502, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Itoh
authors.affiliation: Centro de Investigaciones Biológicas (CIB-CSIC), Ramiro de Maetzu 9, 28040 Madrid, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Alfonso
authors.affiliation: Centro de Investigaciones Biológicas (CIB-CSIC), Ramiro de Maetzu 9, 28040 Madrid, Spain.
authors.forename: Germán
authors.initials: G
authors.lastname: Rivas
authors.affiliation: Center for Integrated Protein Science (CIPSM) at the Department Chemie, Technische Universität München, 85747 Garching, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Buchner
authors.affiliation: Centro Nacional de Biotecnología (CNB-CSIC), Darwin, 3, 28049 Madrid, Spain.
authors.forename: José M
authors.initials: JM
authors.lastname: Valpuesta
mesh_terms: D050956:HSP40 Heat-Shock Proteins / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism* / Q000648:ultrastructure; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism* / Q000648:ultrastructure; D006360:Heat-Shock Proteins / Q000648:ultrastructure; D006801:Humans; D008854:Microscopy, Electron; D011485:Protein Binding; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D011965:Receptors, Glucocorticoid / Q000378:metabolism
chemical_list: D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D018841:HSP90 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D011965:Receptors, Glucocorticoid; C079373:STIP1 protein, human