scholarly journals DUK114, the Drosophila orthologue of bovine brain calpain activator protein, is a molecular chaperone

2004 ◽  
Vol 383 (1) ◽  
pp. 165-170 ◽  
Author(s):  
Attila FARKAS ◽  
Gábor NARDAI ◽  
Peter CSERMELY ◽  
Peter TOMPA ◽  
Peter FRIEDRICH
Keyword(s):  
Heat Shock ◽  
Molecular Chaperone ◽  
Molecular Chaperones ◽  
Citrate Synthase ◽  
Sequence Similarity ◽  
Heat Shock Protein 90 ◽  
Chaperone Activity ◽  
In Vitro Assays

UK114, the goat liver tumour antigen, is a member of a widely distributed family of conserved low-molecular-mass proteins (YER057c/YjgF/UK114), the function of which is ill understood. To the various orthologues diverse functions have been ascribed, such as translation inhibition, regulation of purine repressor or calpain activation. Owing to a limited sequence similarity to Hsp90 (heat-shock protein 90), they have also been proposed to be molecular chaperones; however, this has never been tested. In the present paper, we report the cloning and characterization of the Drosophila orthologue, DUK114. In brief, DUK114 had no effect that would have qualified it as a calpain activator. In contrast, it proved to be a very potent molecular chaperone in in vitro assays. In a heat-aggregation test, it significantly decelerated the formation of citrate synthase aggregates. In a reverse assay, the recovery of the enzyme from urea- and heat-induced denatured states was accelerated almost 3-fold. On a molar basis, the chaperone activity of the 15-kDa DUK114 is comparable with that of Hsp90, the almost 6-times-larger archetypal molecular chaperone. In similar assays, DUK114 was ineffective with Drosophila calpain A or calpain B. To test for its chaperone activity in vivo, DUK114 was transfected into Schneider (S2) cells; after heat shock, the number of viable non-transfected cells started to increase after a lag time; in the presence of DUK114, cell proliferation started at once. Our work is the first experimental evidence that DUK114, and possibly other members of this family, are molecular chaperones.

Inhibition of the heat shock protein 90 molecular chaperone in vitro and in vivo by novel, synthetic, potent resorcinylic pyrazole/isoxazole amide analogues

2007 ◽  
Vol 6 (4) ◽  
pp. 1198-1211 ◽  
Author(s):  
Swee Y. Sharp ◽  
Chrisostomos Prodromou ◽  
Kathy Boxall ◽  
Marissa V. Powers ◽  
Joanna L. Holmes ◽  
...  
Keyword(s):  
Heat Shock ◽  
Heat Shock Protein ◽  
Molecular Chaperone ◽  
Heat Shock Protein 90

scholarly journals Hsp90 is a direct target of the anti-allergic drugs disodium cromoglycate and amlexanox

2003 ◽  
Vol 374 (2) ◽  
pp. 433-441 ◽  
Author(s):  
Miki OKADA ◽  
Hideaki ITOH ◽  
Takashi HATAKEYAMA ◽  
Hiroshi TOKUMITSU ◽  
Ryoji KOBAYASHI
Keyword(s):  
Citrate Synthase ◽  
Heat Shock Protein 90 ◽  
Chaperone Activity ◽  
Physiological Significance ◽  
Disodium Cromoglycate ◽  
Terminal Domain ◽  
C Terminus

Hsp90 (heat-shock protein 90) alone can act to prevent protein aggregation and promote refolding in vitro, but in vivo it operates as a part of a multichaperone complex, which includes Hsp70 and cohort proteins. Since the physiological function of Hsp90 is not yet fully understood, the development of specific antagonists might open new lines of investigation on the role of Hsp90. In an effort to discover Hsp90 antagonists, we screened many drugs and found that the anti-allergic drugs DSCG (disodium cromoglycate) and amlexanox target Hsp90. Both drugs were found to bind directly wild-type Hsp90 via the N- and C-terminal domains. Both drugs strongly suppressed the in vitro chaperone activity of native Hsp90 towards citrate synthase at 1.5–3.0 μM. Amlexanox suppressed C-terminal chaperone activity in vitro, but not N-terminal chaperone activity, and inhibited the association of cohort proteins, such as cyclophilin 40 and Hsp-organizing protein, to the C-terminal domain of Hsp90. These data suggest that amlexanox might disrupt the multichaperone complex, including Hsp70 and cohort proteins, both in vitro and in vivo. Although DSCG inhibited the in vitro chaperone activity of the N-terminal domain, the drug had no effect either on the C-terminal chaperone activity or on the association of the cohort proteins with the C-terminus of Hsp90. The physiological significance of these interactions in vivo remains to be investigated further, but undoubtedly must be taken into account when considering the pharmacology of anti-allergic drugs. DSCG and amlexanox may serve as useful tools for evaluating the physiological significance of Hsp90.

scholarly journals The Effect of Oxidized Dopamine on the Structure and Molecular Chaperone Function of the Small Heat-Shock Proteins, αB-Crystallin and Hsp27

2021 ◽  
Vol 22 (7) ◽  
pp. 3700
Author(s):  
Junna Hayashi ◽  
Jennifer Ton ◽  
Sparsh Negi ◽  
Daniel E. K. M. Stephens ◽  
Dean L. Pountney ◽  
...  
Keyword(s):  
Heat Shock ◽  
Protein Aggregation ◽  
Molecular Chaperone ◽  
Cross Linking ◽  
Αb Crystallin ◽  
The Cross ◽  
Shock Proteins ◽  
And Function

Oxidation of the neurotransmitter, dopamine (DA), is a pathological hallmark of Parkinson’s disease (PD). Oxidized DA forms adducts with proteins which can alter their functionality. αB-crystallin and Hsp27 are intracellular, small heat-shock molecular chaperone proteins (sHsps) which form the first line of defense to prevent protein aggregation under conditions of cellular stress. In vitro, the effects of oxidized DA on the structure and function of αB-crystallin and Hsp27 were investigated. Oxidized DA promoted the cross-linking of αB-crystallin and Hsp27 to form well-defined dimer, trimer, tetramer, etc., species, as monitored by SDS-PAGE. Lysine residues were involved in the cross-links. The secondary structure of the sHsps was not altered significantly upon cross-linking with oxidized DA but their oligomeric size was increased. When modified with a molar equivalent of DA, sHsp chaperone functionality was largely retained in preventing both amorphous and amyloid fibrillar aggregation, including fibril formation of mutant (A53T) α-synuclein, a protein whose aggregation is associated with autosomal PD. In the main, higher levels of sHsp modification with DA led to a reduction in chaperone effectiveness. In vivo, DA is sequestered into acidic vesicles to prevent its oxidation and, intracellularly, oxidation is minimized by mM levels of the antioxidant, glutathione. In vitro, acidic pH and glutathione prevented the formation of oxidized DA-induced cross-linking of the sHsps. Oxidized DA-modified αB-crystallin and Hsp27 were not cytotoxic. In a cellular context, retention of significant chaperone functionality by mildly oxidized DA-modified sHsps would contribute to proteostasis by preventing protein aggregation (particularly of α-synuclein) that is associated with PD.

scholarly journals A Brain Penetrating Heat-Shock Protein 90 Inhibitor NXD30001 Inhibits Glioblastoma as a Monotherapy or in Combination With Radiation

Neurosurgery ◽  
2019 ◽  
Vol 66 (Supplement_1) ◽  
Author(s):  
Hao Chen ◽  
Jialiang Wang ◽  
Hengli Tian
Keyword(s):  
Stem Cells ◽  
Heat Shock ◽  
Heat Shock Protein ◽  
Median Survival ◽  
Therapeutic Potential ◽  
Heat Shock Protein 90 ◽  
Tumor Bearing ◽  
Client Proteins

Abstract INTRODUCTION It has been increasingly recognized that glioblastoma multiforme (GBM) is a highly heterogeneous disease, which is initiated and sustained by molecular alterations in an array of signal transduction pathways. Heat-shock protein 90 (Hsp90) is a molecular chaperone to be critically implicated in folding and activation of a diverse group of client proteins, many of which are key regulators of important glioblastoma biology. METHODS To determine the therapeutic potential of targeting Hsp90 in glioblastoma, we assessed the anti-neoplastic efficacy of NXD30001, a brain-penetrating Hsp90 inhibitor as a monotherapy or in combination with radiation, both in Vitro and in Vivo. RESULTS Our results demonstrated that NXD30001 potently inhibited neurosphere formation, growth and survival of CD133 + glioblastoma stem cells (GSCs) with the half maximal inhibitory concentrations (IC50) at low nanomolar concentrations. At suboptimal concentrations, inhibition of Hsp90 did not exert cytotoxic activity but rather increased radiosensitivity in GSCs. CD133- GBM cells were less sensitive and not radiosensitized by NXD30001. In lines with its cytotoxic and radiosensitizing effects, NXD30001 dose-dependently decreased phosphorylation protein levels of multiple Hsp90 client proteins, including those playing key roles in GSCs, such as EGFR, Akt, c-Myc, and Notch1. In addition, combining NXD30001 with radiation could impair DNA damage response and ER stress response to induce apoptosis of GSCs. Treatment of orthotopic glioblastoma tumors with NXD30001 extended median survival of tumor-bearing mice by approximately 20% (treated 37 days vs vehicle 31 d, P = .0026). Radiation alone increased median survival of tumor-bearing mice from 31 to 38 d, combination with NXD30001 further extended survival to 43 d (P = .0089). CONCLUSION Our results suggest that GBM stem cells (CD133+) are more sensitive to NXD30001 than non-stem GBM cells (CD133-). Furthermore, combination NXD30001 with radiation significantly inhibits GBM progression than use it as a monotherapy by targeting GSCs.

Comparison of Hsc70 orthologs from polar and temperate notothenioid fishes: differences in prevention of aggregation and refolding of denatured proteins

2005 ◽  
Vol 288 (5) ◽  
pp. R1195-R1202 ◽  
Author(s):  
Sean P. Place ◽  
Gretchen E. Hofmann
Keyword(s):  
Molecular Chaperone ◽  
Molecular Chaperones ◽  
Temperate Species ◽  
Effect Of Temperature ◽  
In Vitro Assays ◽  
Comparative Approach ◽  
Antarctic Species ◽  
Temperature Selection ◽  
Lower Temperature

Although a great deal is known about the cellular function of molecular chaperones in general, very little is known about the effect of temperature selection on the function of molecular chaperones in nonmodel organisms. One major unanswered question is whether orthologous variants of a molecular chaperone from differential thermally adapted species vary in their thermal responses. To address this issue, we utilized a comparative approach to examine the temperature interactions of a major cytosolic molecular chaperone, Hsc70, from differently thermally adapted notothenioids. Using in vitro assays, we measured the ability of Hsc70 to prevent thermal aggregation of lactate dehydrogenase (LDH). We further compared the capacity of Hsc70 to refold chemically denatured LDH over the temperature range of −2 to +45°C. Hsc70 purified from the temperate species exhibited greater ability to prevent the thermal denaturation of LDH at 55°C compared with Hsc70 from the cold-adapted species. Furthermore, Hsc70 from the Antarctic species lost the ability to competently refold chemically denatured LDH at a lower temperature compared with Hsc70 from the temperate species. These data indicate the function of Hsc70 in notothenioid fishes maps onto their thermal history and that temperature selection has acted on these molecular chaperones.

Sign in / Sign up

Export Citation Format

Share Document