The charged region of Hsp90 modulates the function of the N-terminal domain

Scheibel, Thomas; Siegmund, Heiko; Jaenicke, Rainer; Ganz, Peter; Lilie, Hauke; Büchner, Johannes

doi:10.1073/pnas.96.4.1297

Cited by 103 publications

(93 citation statements)

References 40 publications

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“…Though the charged region is dispensible in yeast, it has been implicated in the binding of substrates. Truncation mutants containing the N-terminal domain and the charged region show higher affinity for peptide and non-native substrates than mutants lacking the charged region (Scheibel et al, 1999). The yeast and cytosolic higher eukaryotic proteins also have a C-terminal MEEVD peptide that is important in the binding of co-chaperones.…”

Section: Architecture Of Hsp90mentioning

confidence: 99%

Conformational dynamics of the molecular chaperone Hsp90

Krukenberg

Street

Lavery

et al. 2011

Quart. Rev. Biophys.

282

262

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The molecular chaperone Hsp90 is an essential eukaryotic protein that makes up 1-2% of all cytosolic proteins. Hsp90 is vital for the maturation and maintenance of a wide variety of substrate proteins largely involved in signaling and regulatory processes. Many of these substrates have also been implicated in cancer and other diseases making Hsp90 an attractive target for therapeutics. Hsp90 is a highly dynamic and flexible molecule that can adapt its conformation to the wide variety of substrate proteins with which it acts. Large conformational rearrangements are also required for the activation of these client proteins. One driving force for these rearrangements is the intrinsic ATPase activity of Hsp90, as seen with other chaperones. However, unlike other chaperones, studies have shown that the ATPase cycle of Hsp90 is not conformationally deterministic. That is, rather than dictating the conformational state, ATP binding and hydrolysis shifts the equilibrium between a pre-existing set of conformational states in an organismdependent manner. In vivo Hsp90 functions as part of larger heterocomplexes. The binding partners of Hsp90, co-chaperones, assist in the recruitment and activation of substrates, and many co-chaperones further regulate the conformational dynamics of Hsp90 by shifting the conformational equilibrium towards a particular state. Studies have also suggested alternative mechanisms for the regulation of Hsp90's conformation. In this review, we discuss the structural and biochemical studies leading to our current understanding of the conformational dynamics of Hsp90 and the role that nucleotide, co-chaperones, post-translational modification and clients play in regulating Hsp90's conformation. We also discuss the effects of current Hsp90 inhibitors on conformation and the potential for developing small molecules that inhibit Hsp90 by disrupting the conformational dynamics.

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Section: Architecture Of Hsp90mentioning

confidence: 99%

Conformational dynamics of the molecular chaperone Hsp90

Krukenberg

Street

Lavery

et al. 2011

Quart. Rev. Biophys.

282

262

View full text Add to dashboard Cite

show abstract

“…In eukaryotes, a more variable charged region links the N-terminal domain to the core domain. The length and composition of this linker region is highly divergent among organisms [10]. As no atomic resolution structure for full-length Hsp90 is yet available, the most thorough structural analyses for Hsp90, to date, have been based on crystallographic studies of its individual domains.…”

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confidence: 99%

Hsp90—From signal transduction to cell transformation

Brown

Zhu

Schmidt

et al. 2007

Biochemical and Biophysical Research Communications

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The molecular chaperone, Hsp90, facilitates the maturation and/or activation of over 100 'client proteins' involved in signal transduction and transcriptional regulation. Largely an enigma among the families of heat shock proteins, Hsp90 is central to processes broadly ranging from cell cycle regulation to cellular transformation. Here we review the contemporary body of knowledge regarding the biochemical mechanisms of Hsp90 and update the most current paradigms defining its involvement in both normal and pathological cell physiology. KeywordsHsp90; heat shock protein; molecular chaperone; ATPase; genetic capacitor Hsp90 defines a family of molecular chaperones that are highly conserved from prokaryotes to eukaryotes [1][2][3][4][5]. Nonessential for normal growth in most bacteria, Hsp90 is abundantly expressed in higher eukaryotes where it has been shown to be necessary for viability [6,7]. It functions as a homodimer that associates with co-chaperones to catalyze the maturation and/ or activation of over 100 substrate proteins that are known to be involved in cell regulatory pathways [5]. These 'client proteins' include protein kinases, nuclear hormone receptors, transcription factors, and an array of other essential proteins [8]. While much is known regarding the ATPase-driven conformational cycling of Hsp90, the precise physical effects imparted by this chaperone that serve to activate its substrates are still poorly understood [5]. Hsp90 architectureThree highly conserved domains comprise the structure of Hsp90. These include the N-terminal domain, responsible for ATP-binding, a proteolytically resistant core domain, and the Cterminal domain that facilitates homodimerization (Fig. 1a) [9]. In eukaryotes, a more variable charged region links the N-terminal domain to the core domain. The length and composition of this linker region is highly divergent among organisms [10]. As no atomic resolution structure for full-length Hsp90 is yet available, the most thorough structural analyses for Hsp90, to date, have been based on crystallographic studies of its individual domains.A mechanistic understanding of Hsp90 was nebulous until partial sequence homology was recognized between its N-terminal domain and two types of ATP-dependent proteins. These

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“…The intermediate domain consists of a highly charged hinge region (amino acids 206-287) and the following domains similar to the MutL mismatch repair protein and DNA gyrase B (13). The highly charged region increases substrate affinity (14) and is required for chaperone activity (15), although this region is not present in HtpG, an Hsp90 homologue of Escherichia coli (16) and can be deleted without affecting growth in yeast (17). Recently, the middle domain is shown to contribute to cochaperone interaction and binding of client proteins (13,18,19).…”

mentioning

confidence: 99%

Interaction of Neuropeptide Y and Hsp90 through a Novel Peptide Binding Region

et al. 2003

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Hsp90 is a molecular chaperone that binds and assists refolding of non-native and/or labile polypeptides and also bind various peptides. However, the rules of how Hsp90 recognizes substrates have not been well characterized. By surface plasmon resonance measurements, a physiologically active peptide, neuropeptide Y (NPY), with a strong binding property to Hsp90 was identified from screening of 38 randomly selected peptide candidates. We showed that the carboxy-terminal fragment of NPY (NPY13-36), which forms an amphipathic R-helix structure, preserved the strong binding to Hsp90. Immunoprecipitation and immunoblotting using HeLa cell extracts revealed that newly synthesized NPY precursors bound to Hsp90, suggesting that the in vitro binding experiments identified an interactive peptide in vivo. Proteolytic cleavage of the NPY13-36/Hsp90 complex, as well as binding site analysis using deletion mutants of Hsp90, revealed the NPY binding locus on Hsp90R as the 192 amino acid region following the N-terminal domain. By electron microscopic analysis using an anti-Hsp90 antibody against the sequence proximal to the highly charged region, we showed that the Hsp90 dimer bound to NPY13-36 at both ends. Mutation of arginine residues in NPY13-36 to alanine abrogated binding to Hsp90. Our studies indicate that the hinge region after the N-terminal domain of Hsp90 and the positive charges on NPY are important for this interaction.

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The charged region of Hsp90 modulates the function of the N-terminal domain

Cited by 103 publications

References 40 publications

Conformational dynamics of the molecular chaperone Hsp90

Conformational dynamics of the molecular chaperone Hsp90

Hsp90—From signal transduction to cell transformation

Interaction of Neuropeptide Y and Hsp90 through a Novel Peptide Binding Region

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