Unliganded and hormone-bound glucocorticoid receptors interact with distinct hydrophobic sites in the Hsp90 C-terminal domain

Fang, L.; Ricketson, Derek; Getubig, L.; Darimont, Beatrice

doi:10.1073/pnas.0609163103

Cited by 49 publications

(62 citation statements)

References 42 publications

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“…These helices, which show conformational heterogeneity in crystal structures, possibly make contacts that link the interface rearrangements on opposite monomers. Since these helices make important contacts in the proposed interaction site of the glucocorticoid receptor, 33 this speculation suggests a coupling between substrate binding and Hsp90 conformation. Indeed, the closed state of HtpG has been shown to increase anti-aggregation activity for the citrate synthase model substrate.…”

Section: Discussionmentioning

confidence: 99%

Osmolyte‐induced conformational changes in the Hsp90 molecular chaperone

et al. 2009

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Osmolytes are small molecules that play a central role in cellular homeostasis and the stress response by maintaining protein thermodynamic stability at controlled levels. The underlying physical chemistry that describes how different osmolytes impact folding free energy is well understood, however little is known about their influence on other crucial aspects of protein behavior, such as native-state conformational changes. Here we investigate this issue with the Hsp90 molecular chaperone, a large dimeric protein that populates a complex conformational equilibrium. Using small angle X-ray scattering we observe dramatic osmolyte-dependent structural changes within the native ensemble. The degree to which different osmolytes affect the Hsp90 conformation strongly correlates with thermodynamic metrics of their influence on stability. This observation suggests that the well-established osmolyte principles that govern stability also apply to large-scale conformational changes, a proposition that is corroborated by structure-based fitting of the scattering data, surface area comparisons and m-value analysis. This approach shows how osmolytes affect a highly cooperative open/closed structural transition between two conformations that differ by a domain-domain interaction. Hsp90 adopts an additional ligandspecific conformation in the presence of ATP and we find that osmolytes do not significantly affect this conformational change. Together, these results extend the scope of osmolytes by suggesting that they can maintain protein conformational heterogeneity at controlled levels using similar underlying principles that allow them to maintain protein stability; however the relative impact of osmolytes on different structural states can vary significantly.

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Section: Discussionmentioning

confidence: 99%

Osmolyte‐induced conformational changes in the Hsp90 molecular chaperone

et al. 2009

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“…Recent studies by Darimont and coworkers have confirmed that Hsp90 helix 2 stabilizes unliganded GR by engaging apo-GR at the position normally occupied by receptor helix 12 in response to hormonal activation and forcing the flexible helix 12 to bind to the hydrophobic groove, at the same time preventing receptor interaction with coactivators (Fang et al, 2006). The resulting structure corresponds to the native conformation of unliganded GR, with an orientation of helix 12 similar to that in antagonist (RU486)-bound GR (Fang et al, 2006;Kauppi et al, 2003).…”

Section: Flexible Positioning Of Receptor Lbd Helix 12; Hsp90 Helix 2mentioning

confidence: 90%

“…The resulting structure corresponds to the native conformation of unliganded GR, with an orientation of helix 12 similar to that in antagonist (RU486)-bound GR (Fang et al, 2006;Kauppi et al, 2003). On agonist binding, hormone-induced conformational changes within the LBD of holo-GR promote the replacement of Hsp90 helix 2 by receptor helix 12, causing loss of Hsp90 chaperone machinery and establishing the AF2 contact domain for coactivator interaction.…”

Section: Flexible Positioning Of Receptor Lbd Helix 12; Hsp90 Helix 2mentioning

confidence: 99%

“…Core hydrophobic residues within the helix 2 sequence were observed to share sequence similarity with helix 12 of steroid receptors, leading to a proposal that Hsp90 helix 2 acts as a receptor helix 12 mimic in apo-receptor-Hsp90 complexes, occupying the normal activation function 2 (AF2) position of helix 12 following hormone binding (Jackson et al, 2004). Structural elucidation of full-length yeast Hsp90 (Ali et al, 2006) allowed the recognition of helix 1, also consisting of a solvent-exposed, hydrophobic surface within the Hsp90 C-terminal domain, as a possible contact site for protein-protein interactions (Fang et al, 2006). The highly conserved hydrophobic sequence of this helix closely matches the LXXLL recognition motif of the Steroid Receptor Coactivator/p160 family of coactivators that modulate receptor transcriptional activity by interacting with the AF2 agonist-induced hydrophobic groove of nuclear receptors (Ratajczak, 2001).…”

Section: Hsp90 Structure; Amphipathic Helices 1 and 2 In The Hsp90 C-mentioning

confidence: 99%

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Functional Protein Interactions in Steroid Receptor-Chaperone Complexes

Ratajczak¹,

Allan²,

Cluning³

et al. 2012

Protein Interactions

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“…Ricketson and co-workers were able to demonstrate, through amino acid substitution, that this surface is required for HSP90 interaction (Ricketson et al, 2007). HSP90 recognises the GR LBD through two, defined hydrophobic sites and binds to a solvent accessible major groove maintaining GR stability and permitting highaffinity ligand binding (Fang et al, 2006), as depicted in Fig. 7G.…”

Section: Discussionmentioning

confidence: 99%

A ligand-specific kinetic switch regulates glucocorticoid receptor trafficking and function

Trebble

Woolven

Saunders

et al. 2013

Journal of Cell Science

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SummaryThe ubiquitously expressed glucocorticoid receptor (GR) is a major drug target for inflammatory disease, but issues of specificity and target tissue sensitivity remain. We now identify high potency, non-steroidal GR ligands, GSK47867A and GSK47869A, which induce a novel conformation of the GR ligand-binding domain (LBD) and augment the efficacy of cellular action. Despite their high potency, GSK47867A and GSK47869A both induce surprisingly slow GR nuclear translocation, followed by prolonged nuclear GR retention, and transcriptional activity following washout. We reveal that GSK47867A and GSK47869A specifically alter the GR LBD structure at the HSP90-binding site. The alteration in the HSP90-binding site was accompanied by resistance to HSP90 antagonism, with persisting transactivation seen after geldanamycin treatment. Taken together, our studies reveal a new mechanism governing GR intracellular trafficking regulated by ligand binding that relies on a specific surface charge patch within the LBD. This conformational change permits extended GR action, probably because of altered GR-HSP90 interaction. This chemical series may offer anti-inflammatory drugs with prolonged duration of action due to altered pharmacodynamics rather than altered pharmacokinetics.

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Unliganded and hormone-bound glucocorticoid receptors interact with distinct hydrophobic sites in the Hsp90 C-terminal domain

Cited by 49 publications

References 42 publications

Osmolyte‐induced conformational changes in the Hsp90 molecular chaperone

Osmolyte‐induced conformational changes in the Hsp90 molecular chaperone

Functional Protein Interactions in Steroid Receptor-Chaperone Complexes

A ligand-specific kinetic switch regulates glucocorticoid receptor trafficking and function

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