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Journal ArticleDOI

HSP90 at the hub of protein homeostasis: emerging mechanistic insights

01 Jul 2010-Nature Reviews Molecular Cell Biology (Nature Publishing Group)-Vol. 11, Iss: 7, pp 515-528
TL;DR: Comprehensive understanding of how HSP90 functions promises not only to provide new avenues for therapeutic intervention, but to shed light on fundamental biological questions.
Abstract: Heat shock protein 90 (HSP90) is a highly conserved molecular chaperone that facilitates the maturation of a wide range of proteins (known as clients). Clients are enriched in signal transducers, including kinases and transcription factors. Therefore, HSP90 regulates diverse cellular functions and exerts marked effects on normal biology, disease and evolutionary processes. Recent structural and functional analyses have provided new insights on the transcriptional and biochemical regulation of HSP90 and the structural dynamics it uses to act on a diverse client repertoire. Comprehensive understanding of how HSP90 functions promises not only to provide new avenues for therapeutic intervention, but to shed light on fundamental biological questions.
Citations
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Journal ArticleDOI
21 Jul 2011-Nature
TL;DR: It is suggested that an age-related decline in proteostasis capacity allows the manifestation of various protein-aggregation diseases, including Alzheimer's disease and Parkinson's disease, which may spring from a detailed understanding of the pathways underlying proteome maintenance.
Abstract: Most proteins must fold into defined three-dimensional structures to gain functional activity. But in the cellular environment, newly synthesized proteins are at great risk of aberrant folding and aggregation, potentially forming toxic species. To avoid these dangers, cells invest in a complex network of molecular chaperones, which use ingenious mechanisms to prevent aggregation and promote efficient folding. Because protein molecules are highly dynamic, constant chaperone surveillance is required to ensure protein homeostasis (proteostasis). Recent advances suggest that an age-related decline in proteostasis capacity allows the manifestation of various protein-aggregation diseases, including Alzheimer's disease and Parkinson's disease. Interventions in these and numerous other pathological states may spring from a detailed understanding of the pathways underlying proteome maintenance.

2,803 citations

Journal ArticleDOI
TL;DR: This Review summarizes the concepts of the protective Hsp network, and the most conserved Hsps are molecular chaperones that prevent the formation of nonspecific protein aggregates and assist proteins in the acquisition of their native structures.

1,570 citations


Cites background from "HSP90 at the hub of protein homeost..."

  • ...…in prokaryotes to the most sophisticated chaperone machinery known in eukaryotes, working together with a large cohort of cochaperones that associate in a defined order during the chaperone cycle (Figure 3) (Pearl and Prodromou, 2006; Taipale et al., 2010; Wandinger et al., 2008; Li et al., 2010)....

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  • ...Third, it appears to have evolved from a single component system in prokaryotes to the most sophisticated chaperone machinery known in eukaryotes, working together with a large cohort of cochaperones that associate in a defined order during the chaperone cycle (Figure 3) (Pearl and Prodromou, 2006; Taipale et al., 2010; Wandinger et al., 2008; Li et al., 2010)....

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Journal ArticleDOI
TL;DR: Targeted therapies and cytotoxic agents also modulate immune responses, which raises the possibility that these treatment strategies might be effectively combined with immunotherapy to improve clinical outcomes.
Abstract: During the past two decades, the paradigm for cancer treatment has evolved from relatively nonspecific cytotoxic agents to selective, mechanism-based therapeutics. Cancer chemotherapies were initially identified through screens for compounds that killed rapidly dividing cells. These drugs remain the backbone of current treatment, but they are limited by a narrow therapeutic index, significant toxicities and frequently acquired resistance. More recently, an improved understanding of cancer pathogenesis has given rise to new treatment options, including targeted agents and cancer immunotherapy. Targeted approaches aim to inhibit molecular pathways that are crucial for tumour growth and maintenance; whereas, immunotherapy endeavours to stimulate a host immune response that effectuates long-lived tumour destruction. Targeted therapies and cytotoxic agents also modulate immune responses, which raises the possibility that these treatment strategies might be effectively combined with immunotherapy to improve clinical outcomes.

1,298 citations

Journal ArticleDOI
TL;DR: This review focuses on recent advances in understanding the mechanisms of chaperone action in promoting and regulating protein folding and on the pathological consequences of protein misfolding and aggregation.
Abstract: The biological functions of proteins are governed by their three-dimensional fold. Protein folding, maintenance of proteome integrity, and protein homeostasis (proteostasis) critically depend on a complex network of molecular chaperones. Disruption of proteostasis is implicated in aging and the pathogenesis of numerous degenerative diseases. In the cytosol, different classes of molecular chaperones cooperate in evolutionarily conserved folding pathways. Nascent polypeptides interact cotranslationally with a first set of chaperones, including trigger factor and the Hsp70 system, which prevent premature (mis)folding. Folding occurs upon controlled release of newly synthesized proteins from these factors or after transfer to downstream chaperones such as the chaperonins. Chaperonins are large, cylindrical complexes that provide a central compartment for a single protein chain to fold unimpaired by aggregation. This review focuses on recent advances in understanding the mechanisms of chaperone action in promoting and regulating protein folding and on the pathological consequences of protein misfolding and aggregation.

1,249 citations

Journal ArticleDOI
01 Jul 2016-Science
TL;DR: A new view of protein folding is emerging, whereby the energy landscapes that proteins navigate during folding in vivo may differ substantially from those observed during refolding in vitro.
Abstract: Most proteins must fold into unique three-dimensional structures to perform their biological functions. In the crowded cellular environment, newly synthesized proteins are at risk of misfolding and forming toxic aggregate species. To ensure efficient folding, different classes of molecular chaperones receive the nascent protein chain emerging from the ribosome and guide it along a productive folding pathway. Because proteins are structurally dynamic, constant surveillance of the proteome by an integrated network of chaperones and protein degradation machineries is required to maintain protein homeostasis (proteostasis). The capacity of this proteostasis network declines during aging, facilitating neurodegeneration and other chronic diseases associated with protein aggregation. Understanding the proteostasis network holds the promise of identifying targets for pharmacological intervention in these pathologies.

1,009 citations

References
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Journal ArticleDOI
19 Mar 2004-Cell
TL;DR: The high activity mutants signal to ERK by directly phosphorylating MEK, whereas the impaired activity mutants stimulate MEK by activating endogenous C-RAF, possibly via an allosteric or transphosphorylation mechanism.

2,588 citations

Journal ArticleDOI
TL;DR: Pharmacologically 'bribing' the essential guard duty of the chaperone HSP90 (heat-shock protein of 90 kDa) seems to offer a unique anticancer strategy of considerable promise.
Abstract: Standing watch over the proteome, molecular chaperones are an ancient and evolutionarily conserved class of proteins that guide the normal folding, intracellular disposition and proteolytic turnover of many of the key regulators of cell growth, differentiation and survival. This essential guardian function is subverted during oncogenesis to allow malignant transformation and to facilitate rapid somatic evolution. Pharmacologically 'bribing' the essential guard duty of the chaperone HSP90 (heat-shock protein of 90 kDa) seems to offer a unique anticancer strategy of considerable promise.

2,273 citations

Journal ArticleDOI
26 Nov 1998-Nature
TL;DR: It is reported that when Drosophila Hsp90 is mutant or pharmacologically impaired, phenotypic variation affecting nearly any adult structure is produced, with specific variants depending on the genetic background and occurring both in laboratory strains and in wild populations.
Abstract: The heat-shock protein Hsp90 supports diverse but specific signal transducers and lies at the interface of several developmental pathways. We report here that when Drosophila Hsp90 is mutant or pharmacologically impaired, phenotypic variation affecting nearly any adult structure is produced, with specific variants depending on the genetic background and occurring both in laboratory strains and in wild populations. Multiple, previously silent, genetic determinants produced these variants and, when enriched by selection, they rapidly became independent of the Hsp90 mutation. Therefore, widespread variation affecting morphogenic pathways exists in nature, but is usually silent; Hsp90 buffers this variation, allowing it to accumulate under neutral conditions. When Hsp90 buffering is compromised, for example by temperature, cryptic variants are expressed and selection can lead to the continued expression of these traits, even when Hsp90 function is restored. This provides a plausible mechanism for promoting evolutionary change in otherwise entrenched developmental processes.

2,160 citations

Journal ArticleDOI
15 Feb 2008-Science
TL;DR: The proteostasis network is described, a set of interacting activities that maintain the health of proteome and the organism that has the potential to ameliorate some of the most challenging diseases of this era.
Abstract: The protein components of eukaryotic cells face acute and chronic challenges to their integrity. Eukaryotic protein homeostasis, or proteostasis, enables healthy cell and organismal development and aging and protects against disease. Here, we describe the proteostasis network, a set of interacting activities that maintain the health of proteome and the organism. Deficiencies in proteostasis lead to many metabolic, oncological, neurodegenerative, and cardiovascular disorders. Small-molecule or biological proteostasis regulators that manipulate the concentration, conformation, quaternary structure, and/or the location of protein(s) have the potential to ameliorate some of the most challenging diseases of our era.

2,140 citations

Journal ArticleDOI
TL;DR: This review focuses on the composition, regulation and function of cullin–RING ligases, and describes how these enzymes can be characterized by a set of general principles.
Abstract: Cullin–RING complexes comprise the largest known class of ubiquitin ligases. Owing to the great diversity of their substrate-receptor subunits, it is possible that there are hundreds of distinct cullin–RING ubiquitin ligases in eukaryotic cells, which establishes these enzymes as key mediators of post-translational protein regulation. In this review, we focus on the composition, regulation and function of cullin–RING ligases, and describe how these enzymes can be characterized by a set of general principles.

1,985 citations