title: The HSP90 molecular chaperone cycle regulates cyclical transcriptional dynamics of the glucocorticoid receptor and its coregulatory molecules CBP/p300 during ultradian ligand treatment.
abstract: Glucocorticoid (GC) hormones are secreted from the adrenal gland in a characteristic pulsatile pattern. This ultradian secretory activity exhibits remarkable plasticity, with distinct changes in response to both physiological and stressful stimuli in humans and experimental animals. It is therefore important to understand how the pattern of GC exposure regulates intracellular signaling through the GC receptor (GR). We have previously shown that each pulse of ligand initiates rapid, transient GR activation in several physiologically relevant and functionally diverse target cell types. Using chromatin immunoprecipitation assays, we detect cyclical shifts in the net equilibrium position of GR association with regulatory elements of GC-target genes and have investigated in detail the mechanism of pulsatile transcriptional regulation of the GC-induced Period 1 gene. Transient recruitment of the histone acetyl transferase complex cAMP response element-binding protein (CREB) binding protein (CBP)/p300 is found to precisely track the ultradian hormone rhythm, resulting in transient localized net changes in lysine acetylation at GC-regulatory regions after each pulse. Pulsatile changes in histone H4 acetylation and concomitant recruitment of RNA polymerase 2 precede ultradian bursts of Period 1 gene transcription. Finally, we report the crucial underlying role of the intranuclear heat shock protein 90 molecular chaperone complex in pulsatile GR regulation. Pharmacological interference of heat shock protein 90 (HSP90) with geldanamycin during the intranuclear chaperone cycle completely ablated GR's cyclical activity, cyclical cAMP response element-binding protein (CREB) binding protein (CBP)/p300 recruitment, and the associated cyclical acetylation at the promoter region. These data imply a key role for an intact nuclear chaperone cycle in cyclical transcriptional responses, regulated in time by the pattern of pulsatile hormone.
authors.affiliation: Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, University of Bristol, Dorothy Hodgkin Building, Whitson Street, Bristol BS1 3NY, United Kingdom. b.conway-campbell@bristol.ac.uk
authors.forename: Becky L
authors.initials: BL
authors.lastname: Conway-Campbell
authors.forename: Charlotte L
authors.initials: CL
authors.lastname: George
authors.forename: John R
authors.initials: JR
authors.lastname: Pooley
authors.forename: David M
authors.initials: DM
authors.lastname: Knight
authors.forename: Michael R
authors.initials: MR
authors.lastname: Norman
authors.forename: Gordon L
authors.initials: GL
authors.lastname: Hager
authors.forename: Stafford L
authors.initials: SL
authors.lastname: Lightman
mesh_terms: D000107:Acetylation; D000204:Activity Cycles / Q000187:drug effects*; D000818:Animals; D016227:Benzoquinones / Q000494:pharmacology; D050882:CREB-Binding Protein / Q000235:genetics* / Q000378:metabolism; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D047369:Chromatin Immunoprecipitation; D003345:Corticosterone / Q000494:pharmacology*; D018841:HSP90 Heat-Shock Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006657:Histones / Q000378:metabolism; D006801:Humans; D006854:Hydrocortisone / Q000494:pharmacology*; D047029:Lactams, Macrocyclic / Q000494:pharmacology; D007976:Leupeptins / Q000494:pharmacology; D008024:Ligands; D051379:Mice; D056950:Period Circadian Proteins / Q000235:genetics / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D061988:Proteasome Inhibitors; D021381:Protein Transport / Q000187:drug effects; D012319:RNA Polymerase II / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011965:Receptors, Glucocorticoid / Q000235:genetics* / Q000378:metabolism; D050436:Regulatory Elements, Transcriptional; D014158:Transcription, Genetic; D050880:p300-CBP Transcription Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D016227:Benzoquinones; D018841:HSP90 Heat-Shock Proteins; D006657:Histones; D047029:Lactams, Macrocyclic; D007976:Leupeptins; D008024:Ligands; D056950:Period Circadian Proteins; D061988:Proteasome Inhibitors; D012333:RNA, Messenger; D011965:Receptors, Glucocorticoid; D050882:CREB-Binding Protein; D050880:p300-CBP Transcription Factors; D012319:RNA Polymerase II; D046988:Proteasome Endopeptidase Complex; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde; D003345:Corticosterone; D006854:Hydrocortisone; C001277:geldanamycin