Structure of Hsp90-p23-GR reveals the Hsp90 client-remodelling mechanism

Article

关键词: HEAT-SHOCK-PROTEIN;    C-TERMINAL REGION;    GLUCOCORTICOID-RECEPTOR;    STEROID-RECEPTOR;    CRYSTAL-STRUCTURE;    EVOLUTIONARY CONSERVATION;    MOLECULAR CHAPERONES;    SECONDARY STRUCTURE;    HUMAN P23;    BINDING;   

DOI  :  10.1038/s41586-021-04236-1

来源: SCIE

【 摘 要 】

Hsp90 is a conserved and essential molecular chaperone responsible for the folding and activation of hundreds of 'client' proteins(1-3). The glucocorticoid receptor (GR) is a model client that constantly depends on Hsp90 for activity(4-9). GR ligand binding was previously shown to nr inhibited by Hsp70 and restored by Hsp90, aided by the co-chaperone p23(10). However, a molecular understanding of the chaperone-mediated remodelling that occurs between the inactive Hsp70-Hsp90 'client-loading complex' and an activated Hsp90-p23 'client-maturation complex' is lacking for any client, including GR. Here we present a cryo-electron microscopy (cryo-EM) structure of the human GR-maturation complex (GR-Hsp90-p23), revealing that the GR ligand-binding domain is restored to a folded, ligand-bound conformation, while being simultaneously threaded through the Hsp90 lumen. In addition, p23 directly stabilizes native GR using a C-terminal helix, resulting in enhanced ligand binding. This structure of a client bound to Hsp90 in a native conformation contrasts sharply with the unfolded kinase-Hsp90 structure(11). Thus, aided by direct co-chaperone-client interactions, Hsp90 can directly dictate client-specific folding outcomes. Together with the GR-loading complex structure(12), we present the molecular mechanism of chaperone-mediated GR remodelling, establishing the first, to our knowledge, complete chaperone cycle for any Hsp90 client.

【 授权许可】

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