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Protein chaperones

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https://www.readbyqxmd.com/read/28732045/the-exported-chaperone-hsp70-x-supports-virulence-functions-for-plasmodium-falciparum-blood-stage-parasites
#1
Sarah C Charnaud, Matthew W A Dixon, Catherine Q Nie, Lia Chappell, Paul R Sanders, Thomas Nebl, Eric Hanssen, Matthew Berriman, Jo-Anne Chan, Adam J Blanch, James G Beeson, Julian C Rayner, Jude M Przyborski, Leann Tilley, Brendan S Crabb, Paul R Gilson
Malaria is caused by five different Plasmodium spp. in humans each of which modifies the host erythrocyte to survive and replicate. The two main causes of malaria, P. falciparum and P. vivax, differ in their ability to cause severe disease, mainly due to differences in the cytoadhesion of infected erythrocytes (IE) in the microvasculature. Cytoadhesion of P. falciparum in the brain leads to a large number of deaths each year and is a consequence of exported parasite proteins, some of which modify the erythrocyte cytoskeleton while others such as PfEMP1 project onto the erythrocyte surface where they bind to endothelial cells...
2017: PloS One
https://www.readbyqxmd.com/read/28731225/decreased-levels-of-pdi-and-p5-in-oligodendrocytes-in-alzheimer-s-disease
#2
Yasuyuki Honjo, Takashi Ayaki, Takami Tomiyama, Tomohisa Horibe, Hidefumi Ito, Hiroshi Mori, Ryosuke Takahashi, Koji Kawakami
Protein disulfide isomerase (PDI) is a chaperone protein located in the endoplasmic reticulum (ER). Nitric oxide-induced S-nitrosylation of PDI inhibits its enzymatic activity, leading to protein accumulation and activation of the unfolded protein response. Protein disulfide isomerase P5 (P5) is a member of the PDI family that mostly localizes to the ER lumen. Both S-nitrosylated PDI and S-nitrosylated P5 are found in Alzheimer's disease (AD) brain. Previously, we showed that expression of the ER stress marker, growth arrest, and DNA damage protein (GADD34) was significantly increased in neurons and oligodendrocytes in AD brain...
July 21, 2017: Neuropathology: Official Journal of the Japanese Society of Neuropathology
https://www.readbyqxmd.com/read/28729925/patterns-of-production-of-collagen-rich-deposits-in-peripheral-nerves-in-response-to-injury-a-pilot-study-in-a-rabbit-model
#3
Michael Rivlin, Andrew Miller, Jacob Tulipan, Pedro K Beredjiklian, Mark L Wang, Jolanta Fertala, Andrzej Steplewski, James Kostas, Andrzej Fertala
INTRODUCTION: Although collagen-rich deposits are the main component of neural scars, the patterns of their formation are ill defined. Essential to the biosynthesis of collagen fibrils are enzymes catalyzing posttranslational modifications and chaperones that control the formation of the collagen triple helix. Prolyl-4-hydroxylase (P4H) and heat shock protein-47 (HSP47) play a key role, and their production is upregulated during scar formation in human tissues. Alpha smooth muscle actin (αSMA) is also produced during fibrotic processes in myofibroblasts that participate in fibrotic response...
July 2017: Brain and Behavior
https://www.readbyqxmd.com/read/28724966/acetylation-induced-tdp-43-pathology-is-suppressed-by-an-hsf1-dependent-chaperone-program
#4
Ping Wang, Connor M Wander, Chao-Xing Yuan, Michael S Bereman, Todd J Cohen
TDP-43 pathology marks a spectrum of multisystem proteinopathies including amyotrophic lateral sclerosis, frontotemporal lobar degeneration, and sporadic inclusion body myositis. Surprisingly, it has been challenging to recapitulate this pathology, highlighting an incomplete understanding of TDP-43 regulatory mechanisms. Here we provide evidence supporting TDP-43 acetylation as a trigger for disease pathology. Using cultured cells and mouse skeletal muscle, we show that TDP-43 acetylation-mimics promote TDP-43 phosphorylation and ubiquitination, perturb mitochondria, and initiate degenerative inflammatory responses that resemble sporadic inclusion body myositis pathology...
July 19, 2017: Nature Communications
https://www.readbyqxmd.com/read/28724898/improvement-in-the-production-of-the-human-recombinant-enzyme-n-acetylgalactosamine-6-sulfatase-rhgalns-in-escherichia-coli-using-synthetic-biology-approaches
#5
Luis H Reyes, Carolina Cardona, Luisa Pimentel, Alexander Rodríguez-López, Carlos J Alméciga-Díaz
Previously, we demonstrated production of an active recombinant human N-acetylgalactosamine-6-sulfatase (rhGALNS) enzyme in Escherichia coli as a potential therapeutic alternative for mucopolysaccharidosis IVA. However, most of the rhGALNS produced was present as protein aggregates. Here, several methods were investigated to improve production and activity of rhGALNS. These methods involved the use of physiologically-regulated promoters and alternatives to improve protein folding including global stress responses (osmotic shock), overexpression of native chaperones, and enhancement of cytoplasmic disulfide bond formation...
July 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28724793/a-bag3-chaperone-complex-maintains-cardiomyocyte-function-during-proteotoxic-stress
#6
Luke M Judge, Juan A Perez-Bermejo, Annie Truong, Alexandre Js Ribeiro, Jennie C Yoo, Christina L Jensen, Mohammad A Mandegar, Nathaniel Huebsch, Robyn M Kaake, Po-Lin So, Deepak Srivastava, Beth L Pruitt, Nevan J Krogan, Bruce R Conklin
Molecular chaperones regulate quality control in the human proteome, pathways that have been implicated in many diseases, including heart failure. Mutations in the BAG3 gene, which encodes a co-chaperone protein, have been associated with heart failure due to both inherited and sporadic dilated cardiomyopathy. Familial BAG3 mutations are autosomal dominant and frequently cause truncation of the coding sequence, suggesting a heterozygous loss-of-function mechanism. However, heterozygous knockout of the murine BAG3 gene did not cause a detectable phenotype...
July 20, 2017: JCI Insight
https://www.readbyqxmd.com/read/28723972/correction-chaperone-mediated-autophagy-protein-bag3-negatively-regulates-ebola-and-marburg-vp40-mediated-egress
#7
Jingjing Liang, Cari A Sagum, Mark T Bedford, Sachdev S Sidhu, Marius Sudol, Ziying Han, Ronald N Harty
[This corrects the article DOI: 10.1371/journal.ppat.1006132.].
July 2017: PLoS Pathogens
https://www.readbyqxmd.com/read/28721857/stress-adaptation
#8
Alistair J P Brown, Leah E Cowen, Antonio di Pietro, Janet Quinn
Fungal species display an extraordinarily diverse range of lifestyles. Nevertheless, the survival of each species depends on its ability to sense and respond to changes in its natural environment. Environmental changes such as fluctuations in temperature, water balance or pH, or exposure to chemical insults such as reactive oxygen and nitrogen species exert stresses that perturb cellular homeostasis and cause molecular damage to the fungal cell. Consequently, fungi have evolved mechanisms to repair this damage, detoxify chemical insults, and restore cellular homeostasis...
July 2017: Microbiology Spectrum
https://www.readbyqxmd.com/read/28720827/small-chaperons-and-autophagy-protected-neurons-from-necrotic-cell-death
#9
Ye Lei, Kai Liu, Lin Hou, Lianggong Ding, Yuhong Li, Lei Liu
Neuronal necrosis occurs during early phase of ischemic insult. However, our knowledge of neuronal necrosis is still inadequate. To study the mechanism of neuronal necrosis, we previously established a Drosophila genetic model of neuronal necrosis by calcium overloading through expression of a constitutively opened cation channel mutant. Here, we performed further genetic screens and identified a suppressor of neuronal necrosis, CG17259, which encodes a seryl-tRNA synthetase. We found that loss-of-function (LOF) CG17259 activated eIF2α phosphorylation and subsequent up-regulation of chaperons (Hsp26 and Hsp27) and autophagy...
July 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28720726/mitochondrial-cochaperone-mge1-is-involved-in-regulating-susceptibility-to-fluconazole-in-saccharomyces-cerevisiae-and-candida-species
#10
Liesbeth Demuyser, Erwin Swinnen, Alessandro Fiori, Beatriz Herrera-Malaver, Kevin Vestrepen, Patrick Van Dijck
MGE1 encodes a yeast chaperone involved in Fe-S cluster metabolism and protein import into the mitochondria. In this study, we identified MGE1 as a multicopy suppressor of susceptibility to the antifungal fluconazole in the model yeast Saccharomyces cerevisiae We demonstrate that this phenomenon is not exclusively dependent on the integrity of the mitochondrial DNA or on the presence of the drug efflux pump Pdr5. Instead, we show that the increased dosage of Mge1 plays a protective role by retaining increased amounts of ergosterol upon fluconazole treatment...
July 18, 2017: MBio
https://www.readbyqxmd.com/read/28720498/rna-aptamers-targeted-for-human-%C3%AE-a-crystallin-do-not-bind-%C3%AE-b-crystallin-and-spare-the-%C3%AE-crystallin-domain
#11
Prabhat K Mallik, Hua Shi, Jayanti Pande
The molecular chaperones, α-crystallins, belong to the small heat shock protein (sHSP) family and prevent the aggregation and insolubilization of client proteins. Studies in vivo have shown that the chaperone activity of the α-crystallins is raised or lowered in various disease states. Therefore, the development of tools to control chaperone activity may provide avenues for therapeutic intervention, as well as enable a molecular understanding of chaperone function. The major human lens α-crystallins, αA- (HAA) and αB- (HAB), share 57% sequence identity and show similar activity towards some clients, but differing activities towards others...
July 15, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/28720375/protective-role-of-antioxidant-compounds-against-peroxynitrite-mediated-modification-of-r54c-mutant-%C3%AE-a-crystallin
#12
Kazem Khoshaman, Reza Yousefi, Ali Akbar Moosavi-Movahedi
As a highly potent reactive oxygen and nitrogen species, peroxynitrite (PON) has endogenous production in the eye ball and contributes to a variety of ocular disorders. In the current study the structural characteristics, chaperone-like activity and conformational stability of R54C mutant αA-crystallin (αA-Cry) were studied upon modification with PON and in the presence of three antioxidant compounds such as ascorbic acid (ASA), glutathione (GSH) and N-acetylcysteine (NAC) using gel electrophoresis and different spectroscopy methods...
July 15, 2017: Archives of Biochemistry and Biophysics
https://www.readbyqxmd.com/read/28718766/structural-insights-into-the-light-driven-auto-assembly-process-of-the-water-oxidizing-mn4cao5-cluster-in-photosystem-ii
#13
Miao Zhang, Martin Bommer, Ruchira Chatterjee, Rana Hussein, Junko Yano, Holger Dau, Jan Kern, Holger Dobbek, Athina Zouni
In plants, algae and cyanobacteria, Photosystem II (PSII) catalyzes the light-driven splitting of water at a protein-bound Mn4CaO5-cluster, the water-oxidizing complex (WOC). In the photosynthetic organisms, the light-driven formation of the WOC from dissolved metal ions is a key process because it is essential in both initial activation and continuous repair of PSII. Structural information is required for understanding of this chaperone-free metal-cluster assembly. For the first time, we obtained a structure of PSII from Thermosynechococcus elongatus without the Mn4CaO5-cluster...
July 18, 2017: ELife
https://www.readbyqxmd.com/read/28718450/dynamics-and-energetics-of-the-mammalian-phosphatidylinositol-transfer-protein-phospholipid-exchange-cycle
#14
Aby Grabon, Adam Orlowski, Ashutosh Tripathi, Joni Vuorio, Matti Javanainen, Tomasz Róg, Max Lönnfors, Mark I McDermott, Garland Siebert, Pentti Somerharju, Ilpo Vattulainen, Vytas A Bankaitis
Phosphatidylinositol-transfer proteins (PITPs) regulate phosphoinositide signaling in eukaryotic cells. The defining feature of PITPs is their ability to exchange phosphatidylinositol (PtdIns) molecules between membranes, and this property is central to PITP-mediated regulation of lipid signaling. Yet, the details of the PITP-mediated lipid exchange cycle remain entirely obscure. Here, all-atom molecular dynamics (MD) simulations of the mammalian StART-like PtdIns/ phosphatidylcholine (PtdCho) transfer protein PITPα, both on membrane bilayers and in solvated systems, informed downstream biochemical analyses that tested key aspects of the hypotheses generated by the MD simulations...
July 17, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28718449/the-dual-function-chaperone-hych-improves-assembly-of-the-formate-hydrogenlyase-complex
#15
Ute Lindenstrauß, Philipp Skorupa, Jennifer S McDowall, Frank Sargent, Constanze Pinske
The assembly of multi-protein complexes requires the concerted synthesis and maturation of its components and subsequently their co-ordinated interaction. The membrane-bound formate hydrogenlyase (FHL) complex is the primary hydrogen-producing enzyme in Escherichia coli and is composed of seven subunits mostly encoded within the hycA-I operon for [NiFe]-hydrogenase-3 (Hyd-3). The HycH protein is predicted to have an accessory function and is not part of the final structural FHL complex. In this work, a mutant strain devoid of HycH was characterized and found to have significantly reduced FHL activity due to instability of the electron transfer subunits...
July 17, 2017: Biochemical Journal
https://www.readbyqxmd.com/read/28717943/a-pyrrole-based-natural-small-molecule-mitigates-hsp90-expression-in-mda-mb-231-cells-and-inhibits-tumor-angiogenesis-in-mice-by-inactivating-hsf-1
#16
K C Rashmi, H S Atreya, M Harsha Raj, Bharathi P Salimath, H S Aparna
Heat shock proteins (HSPs), molecular chaperones, are crucial for the cancer cells to facilitate proper functioning of various oncoproteins involved in cell survival, proliferation, migration, and tumor angiogenesis. Tumor cells are said to be "addicted" to HSPs. HSPs are overexpressed in many cancers due to upregulation of transcription factor Heat-shock factor 1 (HSF-1), the multifaceted master regulator of heat shock response. Therefore, pharmacological targeting of HSPs via HSF-1 is an effective strategy to treat malignant cancers like triple negative breast cancer...
July 17, 2017: Cell Stress & Chaperones
https://www.readbyqxmd.com/read/28716960/bacterial-tubulin-a-b-exhibit-polarized-growth-mixed-polarity-bundling-and-destabilization-by-gtp-hydrolysis
#17
César Díaz-Celis, Viviana I Risca, Felipe Hurtado, Jessica K Polka, Scott D Hansen, Daniel Maturana, Rosalba Lagos, R Dyche Mullins, Octavio Monasterio
Bacteria of the genus Prosthecobacter express homologs of eukaryotic α- and β-tubulin, called BtubA and BtubB, that have been observed to assemble into filaments in presence of GTP. BtubA/B polymers are proposed to be composed in vitro by two to six protofilaments, in contrast to in vivo where they have been reported to form 5-protofilaments tubes named bacterial microtubules (bMTs). The btubAB genes likely entered the Prosthecobacter lineage via horizontal gene transfer and may derive from an early ancestor of the modern eukaryotic microtubule (MT)...
July 17, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28716523/sensitivity-towards-the-grp78-inhibitor-kp1339-it-139-is-characterized-by-apoptosis-induction-via-caspase-8-upon-disruption-of-er-homeostasis
#18
Beatrix Schoenhacker-Alte, Thomas Mohr, Christine Pirker, Kushtrim Kryeziu, Paul-Steffen Kuhn, Alicia Buck, Thilo Hofmann, Christopher Gerner, Gerrit Hermann, Gunda Koellensperger, Bernhard K Keppler, Walter Berger, Petra Heffeter
The ruthenium drug and GRP78 inhibitor KP1339/IT-139 has already demonstrated promising anticancer activity in a phase I clinical trial. This study aimed to identify mechanisms underlying increased sensitivity to KP1339 treatment. Based on a screen utilizing 23 cell lines, a small panel was selected to compare KP1339-sensitive and low-responsive models. KP1339 sensitivity was neither based on differences in ruthenium accumulation, nor sensitivity to oxidative stress or constituents of KP1339 (ruthenium chloride and indazole)...
July 14, 2017: Cancer Letters
https://www.readbyqxmd.com/read/28716362/phosphoenolpyruvate-phosphotransferase-system-components-positively-regulate-klebsiella-biofilm-formation
#19
Yu-Tze Horng, Chi-Jen Wang, Wen-Ting Chung, Huei-Jen Chao, Yih-Yuan Chen, Po-Chi Soo
BACKGROUND/PURPOSE: Klebsiella pneumoniae is one of the leading causes of device-related infections (DRIs), which are associated with attachment of bacteria to these devices to form a biofilm. The latter is composed of not only bacteria but also extracellular polymeric substances (EPSes) consisting of extracellular DNAs, polysaccharides, and other macromolecules. The phosphoenolpyruvate (PEP):carbohydrate phosphotransferase system (PTS) regulates diverse processes of bacterial physiology...
June 29, 2017: Journal of Microbiology, Immunology, and Infection, Wei Mian Yu Gan Ran za Zhi
https://www.readbyqxmd.com/read/28715732/proteasome-inhibitor-induced-cleavage-of-hsp90-is-mediated-by-ros-generation-and-caspase-10-activation-in-human-leukemic-cells
#20
Sangkyu Park, Jeong-A Park, Hwanmin Yoo, Han-Bum Park, Younghee Lee
Heat shock protein 90 (HSP90) is a molecular chaperone that supports the stability of client proteins. The proteasome is one of the targets for cancer therapy, and studies are underway to use proteasome inhibitors as anti-cancer drugs. In this study, we found that HSP90 was cleaved to a 55kDa protein after treatment with proteasome inhibitors including MG132 in leukemia cells but was not cleaved in other tissue-derived cells. HSP90 has two major isoforms (HSP90α and HSP90β), and both were cleaved by MG132 treatment...
July 12, 2017: Redox Biology
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