title: Conformational processing of oncogenic v-Src kinase by the molecular chaperone Hsp90.
abstract: Hsp90 is a molecular chaperone involved in the activation of numerous client proteins, including many kinases. The most stringent kinase client is the oncogenic kinase v-Src. To elucidate how Hsp90 chaperones kinases, we reconstituted v-Src kinase chaperoning in vitro and show that its activation is ATP-dependent, with the cochaperone Cdc37 increasing the efficiency. Consistent with in vivo results, we find that Hsp90 does not influence the almost identical c-Src kinase. To explain these findings, we designed Src kinase chimeras that gradually transform c-Src into v-Src and show that their Hsp90 dependence correlates with compactness and folding cooperativity. Molecular dynamics simulations and hydrogen/deuterium exchange of Hsp90-dependent Src kinase variants further reveal increased transitions between inactive and active states and exposure of specific kinase regions. Thus, Hsp90 shifts an ensemble of conformations of v-Src toward high activity states that would otherwise be metastable and poorly populated.
authors.affiliation: Center for Integrated Protein Science, Department Chemie, Technische Universität München, 85748 Garching, Germany;
authors.forename: Edgar E
authors.initials: EE
authors.lastname: Boczek
authors.affiliation: Center for Integrated Protein Science, Department Chemie, Technische Universität München, 85748 Garching, Germany;
authors.forename: Lasse G
authors.initials: LG
authors.lastname: Reefschläger
authors.affiliation: Center for Integrated Protein Science, Department Chemie, Technische Universität München, 85748 Garching, Germany; Sandoz Biopharmaceuticals, Hexal AG, 82041 Oberhaching, Germany.
authors.forename: Marco
authors.initials: M
authors.lastname: Dehling
authors.affiliation: Center for Integrated Protein Science, Department Chemie, Technische Universität München, 85748 Garching, Germany;
authors.forename: Tobias J
authors.initials: TJ
authors.lastname: Struller
authors.affiliation: Center for Integrated Protein Science, Department Chemie, Technische Universität München, 85748 Garching, Germany;
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Häusler
authors.affiliation: Sandoz Biopharmaceuticals, Hexal AG, 82041 Oberhaching, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Seidl
authors.affiliation: Center for Integrated Protein Science, Department Chemie, Technische Universität München, 85748 Garching, Germany;
authors.forename: Ville R I
authors.initials: VR
authors.lastname: Kaila
authors.affiliation: Center for Integrated Protein Science, Department Chemie, Technische Universität München, 85748 Garching, Germany; johannes.buchner@tum.de.
authors.forename: Johannes
authors.initials: J
authors.lastname: Buchner
mesh_terms: D000818:Animals; D002645:Chickens; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism*; D056004:Molecular Dynamics Simulation; D015688:Oncogene Protein pp60(v-src) / Q000737:chemistry / Q000378:metabolism*; D011487:Protein Conformation; D011993:Recombinant Fusion Proteins / Q000378:metabolism
chemical_list: D018841:HSP90 Heat-Shock Proteins; D011993:Recombinant Fusion Proteins; D015688:Oncogene Protein pp60(v-src)
keywords: Cdc37; chaperone mechanism; conformational ensembles; kinase activation; metastable states