title: Client Proteins and Small Molecule Inhibitors Display Distinct Binding Preferences for Constitutive and Stress-Induced HSP90 Isoforms and Their Conformationally Restricted Mutants.
abstract: The two cytosolic/nuclear isoforms of the molecular chaperone HSP90, stress-inducible HSP90α and constitutively expressed HSP90β, fold, assemble and maintain the three-dimensional structure of numerous client proteins. Because many HSP90 clients are important in cancer, several HSP90 inhibitors have been evaluated in the clinic. However, little is known concerning possible unique isoform or conformational preferences of either individual HSP90 clients or inhibitors. In this report, we compare the relative interaction strength of both HSP90α and HSP90β with the transcription factors HSF1 and HIF1α, the kinases ERBB2 and MET, the E3-ubiquitin ligases KEAP1 and RHOBTB2, and the HSP90 inhibitors geldanamycin and ganetespib. We observed unexpected differences in relative client and drug preferences for the two HSP90 isoforms, with HSP90α binding each client protein with greater apparent affinity compared to HSP90β, while HSP90β bound each inhibitor with greater relative interaction strength compared to HSP90α. Stable HSP90 interaction was associated with reduced client activity. Using a defined set of HSP90 conformational mutants, we found that some clients interact strongly with a single, ATP-stabilized HSP90 conformation, only transiently populated during the dynamic HSP90 chaperone cycle, while other clients interact equally with multiple HSP90 conformations. These data suggest different functional requirements among HSP90 clientele that, for some clients, are likely to be ATP-independent. Lastly, the two inhibitors examined, although sharing the same binding site, were differentially able to access distinct HSP90 conformational states.
authors.affiliation: Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Prince
authors.affiliation: Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Toshiki
authors.initials: T
authors.lastname: Kijima
authors.affiliation: Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Manabu
authors.initials: M
authors.lastname: Tatokoro
authors.affiliation: Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Sunmin
authors.initials: S
authors.lastname: Lee
authors.affiliation: Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Shinji
authors.initials: S
authors.lastname: Tsutsumi
authors.affiliation: Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Kendrick
authors.initials: K
authors.lastname: Yim
authors.affiliation: Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Candy
authors.initials: C
authors.lastname: Rivas
authors.affiliation: Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Sylvia
authors.initials: S
authors.lastname: Alarcon
authors.affiliation: Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Harvey
authors.initials: H
authors.lastname: Schwartz
authors.affiliation: Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Kofi
authors.initials: K
authors.lastname: Khamit-Kush
authors.affiliation: Radiation Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Bradley T
authors.initials: BT
authors.lastname: Scroggins
authors.affiliation: Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Kristin
authors.initials: K
authors.lastname: Beebe
authors.affiliation: Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Jane B
authors.initials: JB
authors.lastname: Trepel
authors.affiliation: Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Len
authors.initials: L
authors.lastname: Neckers
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D016227:Benzoquinones / Q000494:pharmacology*; D001665:Binding Sites; D004268:DNA-Binding Proteins / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000378:metabolism; D057809:HEK293 Cells; D018841:HSP90 Heat-Shock Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D000076249:Heat Shock Transcription Factors; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D000072019:Kelch-Like ECH-Associated Protein 1; D047029:Lactams, Macrocyclic / Q000494:pharmacology*; D008969:Molecular Sequence Data; D009154:Mutation; D011485:Protein Binding; D011487:Protein Conformation; D020033:Protein Isoforms / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D014230:Triazoles / Q000494:pharmacology*; D025521:Tumor Suppressor Proteins / Q000378:metabolism
chemical_list: D000255:Adenosine Triphosphate; D016227:Benzoquinones; D004268:DNA-Binding Proteins; D019204:GTP-Binding Proteins; D018841:HSP90 Heat-Shock Proteins; D000076249:Heat Shock Transcription Factors; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D047908:Intracellular Signaling Peptides and Proteins; D000072019:Kelch-Like ECH-Associated Protein 1; D047029:Lactams, Macrocyclic; D020033:Protein Isoforms; D047428:Protein Kinase Inhibitors; D018719:Erb-b2 Receptor Tyrosine Kinases; D014157:Transcription Factors; D014230:Triazoles; D025521:Tumor Suppressor Proteins; C000619706:HSF1 protein, human; C431364:KEAP1 protein, human; C497336:RHOBTB2 protein, human; C533237:STA 9090; C508053:ERBB2 protein, human; C001277:geldanamycin