The client protein p53 adopts a molten globule–like state in the presence of Hsp90

Abstract

It is not currently known in what state (folded, unfolded, alternatively folded) client proteins interact with chaperone Hsp90. We show that one client, the p53 DNA-binding domain, undergoes a structural change in the presence of Hsp90 to adopt a molten globule-like state. Addition of one- and two-domain constructs of Hsp90, as well as the full-length three-domain protein, to isotopically-labeled p53 results in reduction in NMR signal intensity throughout p53, particularly its central β-sheet. This reduction appears to be associated with a change of structure of p53 without formation of a distinct complex with Hsp90. Fluorescence and hydrogen-exchange measurements support a loosening in the structure of p53 in the presence of Hsp90 and its domains. We propose that Hsp90 interacts with p53 by multiple transient interactions, forming a dynamic heterogeneous manifold of conformational states that resembles a molten globule.

Chaperones and chaperone–substrate complexes: Dynamic playgrounds for NMR spectroscopists

“…Subsequent studies by the Dyson group employed chemical shift perturbations and hydrogen/deuterium exchange to confirm that p53 core domain is in an unfolded dynamic ensemble [188]. Simultaneously, it was shown that the Hsp90 spectra only showed slight chemical shift changes giving rise to the conclusion that the interaction is highly dynamic [189], whereas another study using yeast Hsp90 by the Kessler group showed a direct interaction via a hydrophilic and salt-dependent patch in the C-terminal domain with a mainly folded p53 core domain [102].…”

“…Park et al investigated the complex between Hsp90 and the core domain of its substrate p53 [188,189], with the intriguing finding that p53 binds Hsp90 in a molten globule-like state [188].…”

Heat stress: A risk factor for skin carcinogenesis

“…Initially, it was originally hypothesised that any heat-mediated changes in keratinocyte biology would be induced by the heat shock response, an evolutionary conserved mechanism for cytoprotection against high temperatures (de Maio et al, 1996;King et al, 2001;Guo et al, 2007) (Chapter 2). Due to the effects of HSP72 and HSP90 on the JNK, p53 and PI3K/Akt pathways (Hagn et al, 2011;Park et al, 2011a;Walerych et al, 2010), an increase in the activity of these heat shock proteins is thought to mediate the protective effects of heat stress on epidermal cells.…”

Targeting heat-shock-protein 90 (Hsp90) by natural products: geldanamycin, a show case in cancer therapy

“…The whole scenario has become more complex by a recent nding that Hsp90 interacts with the p53 client, in that p53 is actually unfolded by Hsp90a, as judged by NMR spectroscopic measurements. 55 As a consequence p53 adopts a molten globule-like state. Thus, Hsp90 should not be solely regarded as a chaperone that simply helps transform its clients into a stable and xed tertiary structure.…”