PubMed Central (PMC3 - NLM DTD)
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Archive of life sciences journal literature at the U.S. National Institutes of Health (NIH), developed and managed by NIH's National Center for Biotechnology Information (NCBI) in the National Library of Medicine (NLM).
Mostrando recursos 121 - 140 de 951
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The human genome encodes 10 ?-crystallinrelated small heat shock proteins: HspB110 - Kappé, Guido; Franck, Erik; Verschuure, Pauline; Boelens, Wilbert C.; Leunissen, Jack A. M.; de Jong, Wilfried W.
To obtain an inventory of all human genes that code for ?-crystallinrelated small heat shock proteins (sHsps), the databases available from the public International Human Genome Sequencing Consortium (IHGSC) and the private Celera human genome project were exhaustively searched. Using the human Hsp27 protein sequence as a query in the protein databases, which are derived from the predicted genes in the human genome, 10 sHsp-like proteins were retrieved, including Hsp27 itself. Repeating the search procedure with all 10 proteins and with a variety of more distantly related animal sHsps, no further human sHsps were detected, as was the case when...
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The sperm outer dense fiber protein is the 10th member of the superfamily of mammalian small stress proteins - Fontaine, Jean-Marc; Rest, Joshua S.; Welsh, Michael J.; Benndorf, Rainer
Nine proteins have been assigned to date to the superfamily of mammalian small heat shock proteins (sHsps): Hsp27 (HspB1, Hsp25), myotonic dystrophy protein kinasebinding protein (MKBP) (HspB2), HspB3, ?A-crystallin (HspB4), ?B-crystallin (HspB5), Hsp20 (p20, HspB6), cardiovascular heat shock protein (cvHsp [HspB7]), Hsp22 (HspB8), and HspB9. The most pronounced structural feature of sHsps is the ?-crystallin domain, a conserved stretch of approximately 80 amino acid residues in the C-terminal half of the molecule. Using the ?-crystallin domain of human Hsp27 as query in a BLAST search, we found sequence similarity with another mammalian protein, the sperm outer dense fiber protein (ODFP)....
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Sea urchin deciliation induces thermoresistance and activates the p38 mitogen-activated protein kinase pathway - Casano, Caterina; Roccheri, Maria Carmela; Maenza, Luisa; Migliore, Silvia; Gianguzza, Fabrizio
In this study, we demonstrate by a variety of approaches (ie, morphological analysis, Western blots, immunolocalization, and the use of specific antibodies) that hyperosmotic deciliation stress of sea urchin embryos induces a thermotolerant response. Deciliation is also able to activate a phosphorylation signaling cascade the effector of which might be the p38 stress-activated protein kinase because we found that the administration of the p38 inhibitor SB203580 to sea urchin deciliated gastrula embryos makes the hyperosmotic deciliation stress lethal.
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Molecular identification and expression of heat shock cognate 70 (hsc70) and heat shock protein 70 (hsp70) genes in the Pacific oyster Crassostrea gigas - Boutet, Isabelle; Tanguy, Arnaud; Rousseau, Sabrina; Auffret, Michel; Moraga, Dario
The 70-kDa heat shock protein (Hsp) family is composed of both environmentally inducible (Hsp) and constitutively expressed (Hsc) family members. We sequenced 2 genes encoding an Hsp70 and an Hsc70 in the Pacific oyster Crassostrea gigas. The Cghsc70 gene contained introns, whereas the Cghsp70 gene did not. Moreover, the corresponding amino acid sequences of the 2 genes presented all the characteristic motifs of the Hsp70 family. We also investigated the expression of Hsp70 in tissues of oysters experimentally exposed to metal. A recombinant Hsc72 was used as an antigen to produce a polyclonal antibody to quantify soluble Hsp70 by enzyme-linked...
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Characterization of the anti-DnaJ monoclonal antibodies and their use to compare immunological properties of DnaJ and its human homologue HDJ-1 - Krzewski, Konrad; Kunikowska, Danuta; Wysocki, Jan; Kotlarz, Agnieszka; Thompkins, Philip; Ashraf, William; Lindsey, Nigel; Picksley, Steven; G?o?nicka, Renata; Lipi?ska, Barbara
Escherichia coli DnaJ (Hsp40) is suspected to participate in rheumatoid arthritis (RA) pathogenesis in humans by an autoimmune process. In this work a set of 6 anti-DnaJ monoclonal antibodies (mAbs) was raised and localization of the epitopes recognized by the mAbs was investigated. Western blotting and enzyme-linked immunosorbent assay (ELISA) experiments showed that the mAbs efficiently bound only native antigen. Using DnaJ mutant proteins with deletions of specified domains and ELISA, we found that AC11 mAb reacted with the best conserved in evolution N-terminal J domain, whereas BB3, EE11, CC5, CC8, and DC7 bound to the C-terminal part after residue...
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Basal and inducible levels of Hsp70 in patients with acute heat illness induced during training - Xiao, Chengfeng; Wu, Tangchun; Ren, Aiming; Pan, Qin; Chen, Sheng; Wu, Fen; Li, Xiaoying; Wang, Ruibo; Hightower, Lawrence E.; Tanguay, Robert M.
Heat shock proteins (Hsps) or stress proteins, and, in particular, the inducible, cytosolic Hsp70, represent a highly conserved response to heat exposure and to a variety of noxious stimuli. Many investigations have shown correlations between the aberrant expression of Hsps and disease states. Whether the basal and inducible levels of Hsp70 are of any biological significance in patients with heat-induced diseases remains unknown. In the present study, we compared the basal and inducible levels of Hsp70 by flow cytometry in lymphocytes of patients with heat-induced diseases and after recovery from this disease, and in matched controls. Both groups comprised individuals...
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Expression of a unique drug-resistant Hsp90 ortholog by the nematode Caenorhabditis elegans - David, Cynthia L.; Smith, Harold E.; Raynes, Deborah A.; Pulcini, Elizabeth J.; Whitesell, Luke
In all species studied to date, the function of heat shock protein 90 (Hsp90), a ubiquitous and evolutionarily conserved molecular chaperone, is inhibited selectively by the natural product drugs geldanamycin (GA) and radicicol. Crystal structures of the N-terminal region of yeast and human Hsp90 have revealed that these compounds interact with the chaperone in a Bergerat-type adenine nucleotidebinding fold shared throughout the gyrase, Hsp90, histidine kinase mutL (GHKL) superfamily of adenosine triphosphatases. To better understand the consequences of disrupting Hsp90 function in a genetically tractable multicellular organism, we exposed the soil-dwelling nematode Caenorhabditis elegans to GA under a variety of...
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p23, a simple protein with complex activities - Felts, Sara J.; Toft, David O.
p23 is a small but important cochaperone for the Hsp90 chaperoning pathway. It appears to facilitate the adenosine triphosphatedriven cycle of Hsp90 binding to client proteins. It enters at a late stage of the cycle and enhances the maturation of client proteins. Although this role of p23 is fairly well established, recent studies suggest that it may have additional functions in the cell that merit further exploration.
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Cdc37 goes beyond Hsp90 and kinases - MacLean, Morag; Picard, Didier
Cdc37 is a relatively poorly conserved and yet essential molecular chaperone. It has long been thought to function primarily as an accessory factor for Hsp90, notably directing Hsp90 to kinases as substrates. More recent discoveries challenge this simplistic view. Cdc37 client proteins other than kinases have now been found, and Cdc37 displays a variety of Hsp90-independent activities both in vitro and in vivo. It can function as a molecular chaperone by itself, interact with other Hsp90 cochaperones in the absence of Hsp90, and even support yeast growth and protein folding without its Hsp90-binding domain. Thus, for many substrates, there may...
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Protection against oxidation during dehydration of yeast - de Jesus Pereira, Elenilda; Panek, Anita Dolly; Eleutherio, Elis Cristina Araujo
Based on the well-documented notion that oxygen affects the stability of dried cells, the role of the cytosolic and mitochondrial forms of superoxide dismutase (Sod) in the capacity of cells to resist dehydration was examined. Both enzymes are important for improving survival, and the absence of only 1 isoform did not impair tolerance against dehydration. In addition, sod strains showed the same Sod activity as the control strain, indicating that the deficiency in either cytoplasmic Cu/Zn or mitochondrial Mn was overcome by an increase in activity of the remaining Sod. To measure the level of intracellular oxidation produced by dehydration,...
132.
Comparison of the carboxy-terminal DP-repeat region in the co-chaperones Hop and Hip - Nelson, Gregory M.; Huffman, Holly; Smith, David F.
Functional steroid receptor complexes are assembled and maintained by an ordered pathway of interactions involving multiple components of the cellular chaperone machinery. Two of these components, Hop and Hip, serve as co-chaperones to the major heat shock proteins (Hsps), Hsp70 and Hsp90, and participate in intermediate stages of receptor assembly. In an effort to better understand the functions of Hop and Hip in the assembly process, we focused on a region of similarity located near the C-terminus of each co-chaperone. Contained within this region is a repeated sequence motif we have termed the DP repeat. Earlier mutagenesis studies implicated the...
133.
Antigenic peptides complexed to phylogenically diverse Hsp70s induce differential immune responses - Kumaraguru, Udayasankar; Gouffon, C. A.; Ivey, R. A.; Rouse, Barry T.; Bruce, Barry D.
The Hsp70 class of heat shock proteins (Hsps) has been implicated at multiple points in the immune response, including initiation of proinflammatory cytokine production, antigen recognition and processing, and phenotypic maturation of antigen-presenting cells (APCs). This class of chaperones is highly conserved in both sequence and structure, from prokaryotes to higher eukaryotes. In all cases, these chaperones function to bind short segments of either peptides or proteins through an adenosine triphosphatedependent process. In addition to a possible role in antigen presentation, these chaperones have also been proposed to function as a potent adjuvant. We compared 4 evolutionary diverse Hsp70s, E....
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Cloning and characterization of a member of the hsp70 gene family from Locusta migratoria, a highly thermotolerant insect - Qin, Wensheng; Tyshenko, Michael G.; Wu, Bernhard S.; Walker, Virginia K.; Robertson, R. Meldrum
A complementary deoxyribonucleic acid (cDNA) and the corresponding gene segment encoding a member of the 70-kDa heat shock protein (Hsp70) family have been cloned and sequenced from Locusta migratoria, the African migratory locust. These animals are noted for their thermotolerance, which can exceed temperatures of 50°C. Conceptually translated, the sequence shows a 654-residue protein with theoretical molecular weight of 71.4 kDa, which more closely resembles the mammalian Hsp70 (8485% similarity) than Hsp70 from other insects, with ?75% similarity to the sequence from the fruit fly. Comparisons of cDNA and genomic sequences show that the gene contains 2 introns, a 245-bp...
135.
Heat shock protein 70 stimulation of the deoxyribonucleic acid base excision repair enzyme polymerase ? - Mendez, Frances; Kozin, Elliott; Bases, Robert
Base excision repair (BER) of damaged deoxyribonucleic acid (DNA) is a multistep process during which potentially lethal abasic sites temporarily exist. Repair of these lesions is greatly stimulated by heat shock protein 70 (Hsp70), which enhances strand incision and removal of the abasic sites by human apurinic-apyrimidinic endonuclease (HAP1). The resulting single-strand gaps must then be filled in. Here, we show that Hsp70 and its 48- and 43-kDa N-terminal domains greatly stimulated filling in the single-strand gaps by DNA polymerase ?, a novel finding that extends the role of Hsps in DNA repair. Incorporation of deoxyguanosine monophosphate (dGMP) to fill...
136.
Oxidative stress impairs intracellular events involved in antigen processing and presentation to T cells - Preynat-Seauve, Olivier; Coudurier, Sylvia; Favier, Alain; Marche, Patrice-Noël; Villiers, Christian
For T cells to recognize foreign antigens, the latter must be processed into peptides and associated to major histocompatibility complex (MHC) class II molecules by antigen-presenting cells (APC). APCs frequently operate under stress conditions induced by tissue damage, antigens, or inflammatory reactions. We analyze the effects of oxidative stress on intracellular processing using APC B cell lines. Before being tested for APC function, B cells (IIA1.6) were exposed for 2 hours to hydrogen peroxide (H2O2), a treatment that impairs their capacity to stimulate specific T cell clones. Because paraformaldehyde-fixed H2O2-treated B cells can still present extracellular peptides to T cell...
137.
Expression levels of heat shock protein 60 in human endothelial cells in vitro are unaffected by exposure to 50 Hz magnetic fields - Henderson, B. R.; Pfister, G.; Boeck, G.; Kind, M.; Wick, G.
Magnetic fields (MFs) from domestic power sources have been implicated as being a potential risk to human health. A number of epidemiological studies have found a significant link between exposure to MFs and increased rates of cancers. There have also been a number of in vivo and in vitro studies reporting effects of MFs in animal disease models and on the expression or activity of a range of proteins. In the past decade, our group proposed that atherosclerosis may have an autoimmune component, with heat shock protein 60 (Hsp60) expressed in endothelial cells as the dominant autoantigen. A number of...
138.
A small heat shock/?-crystallin protein from encysted Artemia embryos suppresses tubulin denaturation - Day, Rossalyn M.; Gupta, Jagdish S.; MacRae, Thomas H.
Small heat shock/?-crystallin proteins function as molecular chaperones, protecting other proteins from irreversible denaturation by an energy-independent process. The brine shrimp, Artemia franciscana, produces a small heat shock/?-crystallin protein termed p26, found in embryos undergoing encystment, diapause, and metabolic arrest. These embryos withstand long-term anoxia and other stresses normally expected to cause death, a property likely dependent on molecular chaperone activity. The association of p26 with tubulin in unfractionated cell-free extracts of Artemia embryos was established by affinity chromatography, suggesting that p26 chaperones tubulin during encystment. To test this possibility, both proteins were purified by modifying published protocols, thereby simplifying...
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Expression levels of heat shock proteins in enterocyte-like Caco-2 cells after exposure to Salmonella enteritidis - Malago, Joshua J.; Koninkx, Jos F. J. G.; Ovelgönne, Hans H.; van Asten, Fons J. A. M.; Swennenhuis, Joost F.; van Dijk, Jaap E.
The enterocytes of the small intestine are occasionally exposed to pathogenic bacteria, such as Salmonella enteritidis 857, an etiologic agent of intestinal infections in humans. The expression of the heat shock response by enterocytes may be part of a protective mechanism developed against pathogenic bacteria in the intestinal lumen. We aimed at investigating whether S enteritidis 857 is able to induce a heat shock response in crypt- and villus-like Caco-2 cells and at establishing the extent of the induction. To establish whether S enteritidis 857 interfered with the integrity of the cell monolayer, the transepithelial electrical resistance (TEER) of filter-grown,...
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