Showing papers by "Jason E. Gestwicki published in 2011"
TL;DR: It is demonstrated that the action of the potent anticancer compound MKT-077 occurs through a differential interaction with Hsp70 allosteric states, and is therefore an "allosteric drug" using NMR spectroscopy.
161 citations
TL;DR: The results suggest that functional pairing of E3s with ataxin-3 or similar DUBs represents an important point of regulation in ubiquitin-dependent protein quality control and shed light on disease pathogenesis in SCA3, a neurodegenerative disorder caused by polyglutamine expansion in ataxIn-3.
154 citations
TL;DR: How chemical probes, such as Congo red, thioflavin T and their derivatives, have been powerful tools for the better understanding of amyloid structure and function are reviewed and how design and deployment of conformationally selective probes might be used to test emerging models of AD are discussed.
Abstract: Alzheimer's disease (AD) is a common neurodegenerative disorder characterized by the deposition of amyloids in the brain. One prominent form of amyloid is composed of repeating units of the amyloid-β (Aβ) peptide. Over the past decade, it has become clear that these Aβ amyloids are not homogeneous; rather, they are composed of a series of structures varying in their overall size and shape and the number of Aβ peptides they contain. Recent theories suggest that these different amyloid conformations may play distinct roles in disease, although their relative contributions are still being discovered. Here, we review how chemical probes, such as Congo red, thioflavin T and their derivatives, have been powerful tools for the better understanding of amyloid structure and function. Moreover, we discuss how design and deployment of conformationally selective probes might be used to test emerging models of AD.
141 citations
TL;DR: This work performed the BCA assays in opaque, white 384-well plates, allowing accurate determination of protein content using only 2 μL of sample, and found that soluble flourescein could replace the white plates, creating a homogenous format.
121 citations
TL;DR: Using NMR, myricetin binds DnaK at an unanticipated site between the IB and IIB subdomains and that it allosterically blocked binding of DnK to DnaJ, highlighting a "gray box" screening approach, which might facilitate the identification of inhibitors of other protein-protein interactions.
100 citations
TL;DR: One potential way to treat tauopathies might be to either accelerate interactions of abnormal tau with these quality control factors or tip the balance of triage towards tau degradation.
Abstract: Tau is a microtubule-associated protein that accumulates in at least 15 different neurodegenerative disorders, which are collectively referred to as tauopathies. In these diseases, tau is often hyperphosphorylated and found in aggregates, including paired helical filaments, neurofibrillary tangles and other abnormal oligomers. Tau aggregates are associated with neuron loss and cognitive decline, which suggests that this protein can somehow evade normal quality control allowing it to aberrantly accumulate and become proteotoxic. Consistent with this idea, recent studies have shown that molecular chaperones, such as heat shock protein 70 and heat shock protein 90, counteract tau accumulation and neurodegeneration in disease models. These molecular chaperones are major components of the protein quality control systems and they are specifically involved in the decision to retain or degrade many proteins, including tau and its modified variants. Thus, one potential way to treat tauopathies might be to either a...
61 citations
TL;DR: A series of dihydropyridines were identified that have an effect on the accumulation of tau, an important target in Alzheimer's disease.
33 citations
TL;DR: Results suggest that partial release of Hsp70 may be an essential step in the continued processing of expanded polyQ fragments in yeast.
26 citations
TL;DR: A model in which Hsp70 binding to apo-nNOS stabilizes an open state of the heme/substrate binding cleft to facilitate thioredoxin access to the active site cysteine that coordinates with heme iron, permitting heme binding and dimerization to theactive enzyme is supported.
Abstract: We have reported that heme-dependent activation of apo-neuronal nitric oxide synthase (apo-nNOS) to the active holo-enzyme dimer is dependent upon factors present in reticulocyte lysate and other cytosols. Here, we find that both Hsp70 and thioredoxin are components of the activation system. The apo-nNOS activating activity of reticulocyte lysate is retained in a pool of fractions containing Hsp70 that elute from DE52 prior to Hsp90. All of the activating activity and 20–30% of the Hsp70 elute in the flow-through fraction upon subsequent ATP-agarose chromatography. Apo-nNOS activation by this flow-through fraction is inhibited by pifithrin-μ, a small molecule inhibitor of Hsp70, suggesting that a non-ATP-binding form of Hsp70 is involved in heme-dependent apo-nNOS activation. Previous work has shown that apo-nNOS can be activated by thiol-disulfide exchange, and we show substantial activation with a small molecule dithiol modeled on the active motifs of thioredoxin and protein disulfide isomerase. Further fractionation of the ATP-agarose flow-through on Sephacryl S-300 separates free thioredoxin from apo-nNOS activating activity, Hsp70, and a small amount of thioredoxin, all of which are eluted throughout the macromolecular peak. Incubation of apo-nNOS with the macromolecular fraction in combination with either the thioredoxin-containing fraction or with purified recombinant human thioredoxin restores full heme-dependent activating activity. This supports a model in which Hsp70 binding to apo-nNOS stabilizes an open state of the heme/substrate binding cleft to facilitate thioredoxin access to the active site cysteine that coordinates with heme iron, permitting heme binding and dimerization to the active enzyme.
18 citations
TL;DR: A modified synthetic route with significantly improved overall yield and modifications of the hemiaminal significantly increased chemical stability is reported, anticipating that this synthetic route will improve access to biologically active 15-DSG derivatives.
15 citations
Patent•
20 Dec 2011
TL;DR: In this article, the absorbance spectrum of a chromophore resulting from the association of the analyte and a precursor agent is used to detect analyte in small volume samples.
Abstract: Disclosed herein are methods of detecting an analyte in a sample. The methods can provide detection of an analyte in small volume samples (up to 12 μί). Further provided herein are devices for detecting analytes, wherein the device is selected based upon an absorbance spectrum of a chromophore resulting from the association of the analyte and a precursor agent.
TL;DR: Hantzsch synthesis and SAR of a series of dihydropyridines (39 examples) with an effect on the accumulation of tau are presented in this article, where the SAR of each dihydro-yridine is evaluated.
Abstract: Hantzsch synthesis and SAR of a series of dihydropyridines (39 examples) with an effect on the accumulation of tau are presented.
Patent•
12 Apr 2011
TL;DR: In this paper, therapeutic hybrid compounds having an active moiety and a toxicity reducing moiety are provided, as well as methods of use of such compounds, methods of preparation of these compounds, and compositions containing such compounds.
Abstract: Therapeutic hybrid compounds having an active moiety and a toxicity reducing moiety are provided, as are methods of use of such compounds, methods of preparation of such compounds, and compositions containing such compounds. In some embodiments, the hybrid compounds have lower toxicity (such as lower neurotoxicity) compared with the non-hybridized active moiety.