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Ju Hui Jeong, Yong Jin Oh, Taeg Kyu Kwon, Young Ho Seo
The molecular chaperone Hsp90 has emerged as an attractive cancer therapeutic target due to its role in cellular homeostasis by modulating the stabilization and maturation of many oncogenic proteins. In this study, we designed and synthesized a series of Hsp90 inhibitors that hybridized NVP-AUY992 (2) and PU3 (3) in the chalcone scaffold using a structure-based approach. Our results indicate that compound 1g inhibited the proliferation of gefitinib-resistant non-small cell lung cancer (H1975) cells, downregulated the expression of client proteins of Hsp90 including EGFR, MET, Her2 and Akt, and up-regulated the expression of Hsp70...
October 21, 2016: Archives of Pharmacal Research
Shu-Yu Wu, Ping Zou, Alexandra W Fuller, Sanjay Mishra, Zhen Wang, Kevin L Schey, Hassane S Mchaourab
The refractivity and transparency of the ocular lens is dependent on the stability and solubility of the crystallins in the fiber cells. A number of mutations of lens crystallins have been associated with dominant cataracts in humans and mice. Of particular interest were γB- and γD-crystallin mutants linked to dominant cataracts in mouse models. While thermodynamically destabilized and aggregation-prone, these mutants were found to have weak affinity to the resident chaperone α-crystallin in vitro To better understand the mechanism of the cataract phenotype, we transgenically expressed different γD-crystallin mutants in the zebrafish lens, and observed a range of lens defects that arise primarily from the aggregation of the mutant proteins...
October 21, 2016: Journal of Biological Chemistry
Greg Hodge, Eugene Roscioli, Hubertus Jersmann, Hai B Tran, Mark Holmes, Paul N Reynolds, Sandra Hodge
BACKGROUND: Corticosteroid resistance is a major barrier to effective treatment of COPD. We have shown that the resistance is associated with decreased expression of glucocorticoid receptor (GCR) by senescent CD28nullCD8+ pro-inflammatory lymphocytes in peripheral blood of COPD patients. GCR must be bound to molecular chaperones heat shock proteins (Hsp) 70 and Hsp90 to acquire a high-affinity steroid binding conformation, and traffic to the nucleus. We hypothesized a loss of Hsp70/90 from these lymphocytes may further contribute to steroid resistance in COPD...
October 21, 2016: Respiratory Research
Kerry A Geiler-Samerotte, Yuan O Zhu, Benjamin E Goulet, David W Hall, Mark L Siegal
The protein-folding chaperone Hsp90 has been proposed to buffer the phenotypic effects of mutations. The potential for Hsp90 and other putative buffers to increase robustness to mutation has had major impact on disease models, quantitative genetics, and evolutionary theory. But Hsp90 sometimes contradicts expectations for a buffer by potentiating rapid phenotypic changes that would otherwise not occur. Here, we quantify Hsp90's ability to buffer or potentiate (i.e., diminish or enhance) the effects of genetic variation on single-cell morphological features in budding yeast...
October 2016: PLoS Biology
Chae Lim Jung, Hyemin Mun, Se-Young Jo, Ju-Hee Oh, ChuHee Lee, Eun-Kyung Choi, Se Jin Jang, Young-Ah Suh
Mutation of p53 occasionally results in a gain of function, which promotes tumor growth. We asked whether destabilizing the gain-of-function protein would kill tumor cells. Downregulation of the gene reduced cell proliferation in p53-mutant cells, but not in p53-null cells, indicating that the former depended on the mutant protein for survival. Moreover, phenformin and 2-deoxyglucose suppressed cell growth and simultaneously destabilized mutant p53. The AMPK pathway, MAPK pathway, chaperone proteins and ubiquitination all contributed to this process...
October 19, 2016: Oncotarget
Nada Lallous, Eric Leblanc, Ravi Sn Munuganti, Mohamed D H Hassona, Nader Al Nakouzi, Shannon Awrey, Helene Morin, Mani Roshan-Moniri, Kriti Singh, Sam Lawn, Takeshi Yamazaki, Hans H Adomat, Christophe Andre, Mads Daugaard, Robert N Young, Emma S Tomlinson Guns, Paul S Rennie, Artem Cherkasov
The development of new anti-androgens such as enzalutamide or androgen synthesis inhibitors like abiraterone have improved patient outcomes in the treatment of advanced prostate cancer (PCa). However, due to the development of drug resistance and tumor cell survival, the majority of these patients progress to the refractory state of castration-resistant prostate cancer (CRPC). Thus, newer therapeutic agents and a better understanding of their mode of action are needed for treating these CRPC patients. We demonstrated previously that targeting the Binding Function 3 (BF3) pocket of the androgen receptor (AR) has great potential for treating patients with CRPC...
October 7, 2016: Molecular Cancer Therapeutics
Silvia Dal Santo, Alberto Palliotti, Sara Zenoni, Giovanni Battista Tornielli, Marianna Fasoli, Paola Paci, Sergio Tombesi, Tommaso Frioni, Oriana Silvestroni, Andrea Bellincontro, Claudio d'Onofrio, Fabiola Matarese, Matteo Gatti, Stefano Poni, Mario Pezzotti
BACKGROUND: Grapevine (Vitis vinifera L.) is an economically important crop with a wide geographical distribution, reflecting its ability to grow successfully in a range of climates. However, many vineyards are located in regions with seasonal drought, and these are often predicted to be global climate change hotspots. Climate change affects the entire physiology of grapevine, with strong effects on yield, wine quality and typicity, making it difficult to produce berries of optimal enological quality and consistent stability over the forthcoming decades...
October 20, 2016: BMC Genomics
Xiaokui Gu, Wei Xue, Yajing Yin, Hongwei Liu, Shaojie Li, Xianyun Sun
Heat Shock Protein 90 (Hsp90) is essential for tumor progression in humans and drug resistance in fungi. However, the roles of its many co-chaperones in antifungal resistance are unknown. In this study, by susceptibility test of Neurospora crassa mutants lacking each of 18 Hsp90/Calcineurin system member genes (including 8 Hsp90 co-chaperone genes) to antifungal drugs and other stresses, we demonstrate that the Hsp90 co-chaperones Sti1 (Hop1 in yeast), Aha1, and P23 (Sba1 in yeast) were required for the basal resistance to antifungal azoles and heat stress...
2016: Frontiers in Microbiology
Chunfeng Chen, Jie Chen, Tianyu Wang, Minghua Liu
Four kinds of commercially available diacetylene (DA) monomers with different chain length, diacetylene positions were fabricated into the organogels via mixing with a chaperone gelator, an amphiphilic L-histidine ester derivative LHC18 that can help the non-gelator to form gels. Upon photo irradiation with a 254 UV light, the white gels underwent topochemical reaction and turned into red or blue gels, depending on the DA monomer structures. Through the gel formation, the molecular chirality of LHC18 can be transferred to the polydiacetylene (PDA) and helical nanoribbon structures were obtained...
October 19, 2016: ACS Applied Materials & Interfaces
Jessica M Wilson, Jeremy W Prokop, Ellen Lorimer, Elizabeth Ntantie, Carol L Williams
Two isoforms of the small GTPase Rap1, Rap1A and Rap1B, participate in cell adhesion; Rap1A promotes steady state adhesion, while Rap1B regulates dynamic changes in cell adhesion. These events depend on the prenylation of Rap1, which promotes its membrane localization. Here, we identify previously unsuspected differences in the regulation of prenylation of Rap1A versus Rap1B, due in part to their different phosphorylation-dependent interactions with the chaperone protein SmgGDS-607. Previous studies indicate that activation of Gαs protein-coupled receptors (GPCRs) phosphorylates S-179 and S-180 in the polybasic region (PBR) of Rap1B, which inhibits Rap1B binding to SmgGDS-607 and diminishes Rap1B prenylation and membrane localization...
October 16, 2016: Journal of Molecular Biology
Marie-Julie Nokin, Florence Durieux, Paul Peixoto, Barbara Chiavarina, Olivier Peulen, Arnaud Blomme, Andrei Turtoi, Brunella Costanza, Nicolas Smargiasso, Dominique Baiwir, Jean L Scheijen, Casper G Schalkwijk, Justine Leenders, Pascal De Tullio, Elettra Bianchi, Marc Thiry, Koji Uchida, David A Spiegel, James R Cochrane, Craig A Hutton, Edwin De Pauw, Philippe Delvenne, Dominique Belpomme, Vincent Castronovo, Akeila Bellahcène
Metabolic reprogramming toward aerobic glycolysis unavoidably induces methylglyoxal (MG) formation in cancer cells. MG mediates the glycation of proteins to form advanced glycation end products (AGEs). We have recently demonstrated that MG-induced AGEs are a common feature of breast cancer. Little is known regarding the impact of MG-mediated carbonyl stress on tumor progression. Breast tumors with MG stress presented with high nuclear YAP, a key transcriptional co-activator regulating tumor growth and invasion...
October 19, 2016: ELife
Takashi Onikubo, David Shechter
Chromatin is the complex of DNA and histone proteins that is the physiological form of the eukaryotic genome. Chromatin is generally repressive for transcription, especially so during early metazoan development when maternal factors are explicitly in control of new zygotic gene expression. In the important model organism Xenopus laevis, maturing oocytes are transcriptionally active with reduced rates of chromatin assembly, while laid eggs and fertilized embryos have robust rates of chromatin assembly and are transcriptionally repressed...
2016: International Journal of Developmental Biology
Carla M Zammit, Florian Weiland, Joël Brugger, Benjamin Wade, Lyron Juan Winderbaum, Dietrich H Nies, Gordon Southam, Peter Hoffmann, Frank Reith
The metal-resistant β-proteobacterium Cupriavidus metallidurans drives gold (Au) biomineralisation and the (trans)formation of Au nuggets largely via unknown biochemical processes, ultimately leading to the reductive precipitation of mobile, toxic Au(i/iii)-complexes. In this study proteomic responses of C. metallidurans CH34 to mobile, toxic Au(iii)-chloride are investigated. Cells were grown in the presence of 10 and 50 μM Au(iii)-chloride, 50 μM Cu(ii)-chloride and without additional metals. Differentially expressed proteins were detected by difference gel electrophoresis and identified by liquid chromatography coupled mass spectrometry...
October 19, 2016: Metallomics: Integrated Biometal Science
Vibhuti Joshi, Ayeman Amanullah, Arun Upadhyay, Ribhav Mishra, Amit Kumar, Amit Mishra
Cells regularly synthesize new proteins to replace old and abnormal proteins for normal cellular functions. Two significant protein quality control pathways inside the cellular milieu are ubiquitin proteasome system (UPS) and autophagy. Autophagy is known for bulk clearance of cytoplasmic aggregated proteins, whereas the specificity of protein degradation by UPS comes from E3 ubiquitin ligases. Few E3 ubiquitin ligases, like C-terminus of Hsc70-interacting protein (CHIP) not only take part in protein quality control pathways, but also plays a key regulatory role in other cellular processes like signaling, development, DNA damage repair, immunity and aging...
2016: Frontiers in Molecular Neuroscience
Barbara Kathage, Sebastian Gehlert, Anna Ulbricht, Laura Lüdecke, Victor E Tapia, Zacharias Orfanos, Daniela Wenzel, Wilhelm Bloch, Rudolf Volkmer, Bernd K Fleischmann, Dieter O Fürst, Jörg Höhfeld
The cochaperone BAG3 is a central protein homeostasis factor in mechanically strained mammalian cells. It mediates the degradation of unfolded and damaged forms of the actin-crosslinker filamin through chaperone-assisted selective autophagy (CASA). In addition, BAG3 stimulates filamin transcription in order to compensate autophagic disposal and to maintain the actin cytoskeleton under strain. Here we demonstrate that BAG3 coordinates protein synthesis and autophagy through spatial regulation of the mammalian target of rapamycin complex 1 (mTORC1)...
October 15, 2016: Biochimica et Biophysica Acta
Sofia Lisanti, David S Garlick, Kelly G Bryant, Michele Tavecchio, Gordon B Mills, Yiling Lu, Andrew V Kossenkov, Louise C Showe, Lucia R Languino, Dario C Altieri
Protein homeostasis, or proteostasis is required for mitochondrial function, but its role in cancer is controversial. Here, we show that transgenic mice expressing the mitochondrial chaperone, TRAP1 in the prostate develop epithelial hyperplasia and cellular atypia. When examined on a Pten+/- background, a common alteration in human prostate cancer, TRAP1 transgenic mice showed accelerated incidence of invasive prostatic adenocarcinoma, characterized by increased cell proliferation and reduced apoptosis, in situ...
October 17, 2016: Journal of Biological Chemistry
Vasily M Studitsky, Ekaterina V Nizovtseva, Alexey K Shaytan, Donal S Luse
Packaging of DNA into chromatin affects all processes on DNA. Nucleosomes present a strong barrier to transcription, raising important questions about the nature and the mechanisms of overcoming the barrier. Recently it was shown that DNA sequence, DNA-histone interactions and backtracking by RNA polymerase II (Pol II) all contribute to formation of the barrier. After partial uncoiling of nucleosomal DNA from histone octamer by Pol II and backtracking of the enzyme, nucleosomal DNA recoils on the octamer, locking Pol II in the arrested state...
2016: Biochemistry & Molecular Biology Journal
Anastasia Mihailidou, Anthony Ashton
OBJECTIVE: Myocardial infarction (MI) continues to be a major burden of disease, despite rapid reperfusion interventions. Reperfusion of ischemic hearts (reperfusion injury) induces free radical generation, activation of early stress responses and apoptosis, which contributes to ventricular remodeling and dysfunction, which may lead to developing heart failure. Mineralocorticoid receptor (MR) antagonists have been shown clinically to reduce blood pressure, particularly in resistant hypertension, and substantially increase survival in heart failure...
September 2016: Journal of Hypertension
Pradyut K Paul, Mary E Rabaglia, Chen-Yu Wang, Donald S Stapleton, Ning Leng, Christina Kendziorski, Peter W Lewis, Mark P Keller, Alan D Attie
Anti-silencing function 1 (ASF1) is a histone H3-H4 chaperone involved in DNA replication and repair, and transcriptional regulation. Here, we identify ASF1B, the mammalian paralog to ASF1, as a proliferation-inducing histone chaperone in human β-cells. Overexpression of ASF1B led to distinct transcriptional signatures consistent with increased cellular proliferation and reduced cellular death. Using multiple methods of monitoring proliferation and mitotic progression, we show that overexpression of ASF1B is sufficient to induce human β-cell proliferation...
October 18, 2016: Cell Cycle
S S Garcia, Q Du, H Wu
The oral cavity is a dynamic environment characterized by hundreds of bacterial species, saliva, and an influx of nutrients and metal ions such as copper. Although there is a physiologic level of copper in the saliva, the oral cavity is often challenged with an influx of copper ions. At high concentrations copper is toxic and must therefore be strictly regulated by pathogens for them to persist and cause disease. The cariogenic pathogen Streptococcus mutans manages excess copper using the copYAZ operon that encodes a negative DNA-binding repressor (CopY), the P1-ATPase copper exporter (CopA), and the copper chaperone (CopZ)...
December 21, 2015: Molecular Oral Microbiology
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