PubMed Central (PMC3 - NLM DTD)
(2,081,148 recursos)
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 141 - 160 de 951
141.
The Bacillus subtilis heat shock stimulon - Schumann, Wolfgang
All organisms respond to a sudden increase in temperature by the so-called heat shock response. This response results in the induction of a subset of genes, designated heat shock genes coding for heat shock proteins, which allow the cell to cope with the stress regimen. Research carried out during the last 10 years with eubacteria has revealed that the heat shock genes of a given species fall into different classes (regulons), where each class is regulated by a different transcriptional regulator, which could be an alternative sigma factor, a transcriptional activator, or a transcriptional repressor. All regulons of a single...
142.
GrpE, a nucleotide exchange factor for DnaK - Harrison, Celia
The cochaperone GrpE functions as a nucleotide exchange factor to promote dissociation of adenosine 5?-diphosphate (ADP) from the nucleotide-binding cleft of DnaK. GrpE and the DnaJ cochaperone act in concert to control the flux of unfolded polypeptides into and out of the substrate-binding domain of DnaK by regulating the nucleotide-bound state of DnaK. DnaJ stimulates nucleotide hydrolysis, and GrpE promotes the exchange of ADP for adenosine triphosphate (ATP) and also augments peptide release from the DnaK substrate-binding domain in an ATP-independent manner. The eukaryotic cytosol does not contain GrpE per se because GrpE-like function is provided by the BAG1 protein,...
143.
BAG-1a nucleotide exchange factor of Hsc70 with multiple cellular functions - Alberti, Simon; Esser, Claudia; Höhfeld, Jörg
BAG-1 (Bcl-2associated athanogene) is a multifaceted protein implicated in the modulation of a large variety of cellular processes. Elucidating the molecular mechanisms that underlie the cellular functions of BAG-1 becomes an increasingly important task, particularly in light of the growing evidence connecting aberrant BAG-1 expression to certain human cancers. A common element of the remarkable functional diversity of BAG-1 appears to be the interaction with molecular chaperones of the Hsp70 family. In fact, BAG-1 functions as a nucleotide exchange factor of mammalian cytosolic Hsc70, thereby triggering substrate unloading from the chaperone. In addition, recent findings reveal an association of BAG-1...
144.
Stress to cadmium monitored by metallothionein gene induction in Paracentrotus lividus embryos - Russo, Roberta; Bonaventura, Rosa; Zito, Francesca; Schröder, Heinz-C.; Müller, Isabel; Müller, Werner E. G.; Matranga, Valeria
We used sea urchin embryos as bioindicators to study the effects of exposure to sublethal cadmium concentrations on the expression of the metallothionein (MT) gene stress marker. For this purpose, the complete complementary deoxyribonucleic acid of the species Paracentrotus lividus (Pl) was cloned and sequenced. Northern blot analysis showed that basal levels of Pl-MT messenger ribonucleic acid, having an apparent size of 700 bases, are expressed in all developmental stages analyzed, from early cleavage to pluteus. However, when embryos were continuously cultured in sublethal CdCl2 concentrations and harvested at cleavage, swimming blastula, late gastrula, and pluteus stages (6, 12, 24,...
145.
Induction of heat shock protein gp96 by immune cytokines - Chen, Y. G.; Ashok, B. T.; Liu, X.; Garikapaty, V. P. S.; Mittelman, A.; Tiwari, R. K.
Cytokines play a major role in regulating both humoral and cell-mediated immune responses. Recent advances in our understanding of cell-mediated immune responses have focused on the antigen presentation machinery and the proteins in the endoplasmic reticulum (ER). These proteins help the formation and stabilization of the major histocompatibility complex (MHC)peptide interaction. A 96-kDa, ER-resident glycoprotein (gp96) is being evaluated as a therapeutic agent in cancer because of its ability to associate with a vast number of cellular peptides irrespective of size or sequence. Because the antigen presentation complex is assembled in the ER and a number of ER-resident proteins are...
146.
Overexpression of Hsp27 in a human melanoma cell line: regulation of E-cadherin, MUC18/MCAM, and plasminogen activator (PA) system - Aldrian, Silke; Kindas-Mügge, Ingela; Trautinger, Franz; Fröhlich, Ilse; Gsur, Andrea; Herbacek, Irene; Berger, Walter; Micksche, Michael
Hsp27 is considered a potential marker for cell differentiation in diverse tissues. Several aspects linked to the differentiation process and to the transition from high to low metastatic potential were analyzed in melanoma cells transfected with Hsp27. E-cadherin plays a central role in cell differentiation, migration, and normal development. Loss of expression or function of E-cadherin has been documented in a variety of human malignancies. We observed by fluorescence-activated cell sorter (FACS) as well as immunofluorescence (IF) analysis a pronounced expression of E-cadherin in Hsp27-transfected A375 melanoma cells compared with control melanoma cells. The expression of the adhesion molecule MUC18/MCAM...
147.
Molt cycledependent molecular chaperone and polyubiquitin gene expression in lobster - Spees, Jeffrey L.; Chang, Sharon A.; Mykles, Donald L.; Snyder, Mark J.; Chang, Ernest S.
Lobster claw muscle undergoes atrophy in correlation with increasing ecdysteroid (steroid molting hormone) titers during premolt. In vivo molecular chaperone (constitutive heat shock protein 70 [Hsc70], heat shock protein 70 [Hsp70], and Hsp90) and polyubiquitin messenger ribonucleic acid (mRNA) levels were examined in claw and abdominal muscles from individual premolt or intermolt lobsters. Polyubiquitin gene expression was assayed as a marker for muscle atrophy. Both Hsc70 and Hsp90 mRNA levels were significantly induced in premolt relative to intermolt lobster claw muscle, whereas Hsp70 mRNA levels were not. Hsp90 gene expression was significantly higher in premolt claw muscle when compared with...
148.
Bacterial stimulation upregulates the surface expression of the stress protein gp96 on B cells in the frog Xenopus - Morales, Heidi; Muharemagic, Alma; Gantress, Jennifer; Cohen, Nicholas; Robert, Jacques
The presence of the soluble intracellular heat shock protein gp96 (an endoplasmic reticulum resident protein) at the surface of certain cell types is an intriguing phenomenon whose physiological significance has been unclear. We have shown that the active surface expression of gp96 by some immune cells is found throughout the vertebrate phylum including the Agnatha, the only vertebrate taxon whose members (lamprey, hagfish) lack an adaptive immune system. To determine whether gp96 surface expression can be modulated by pathogens, we investigated the effects of in vitro stimulation by purified lipopolysaccharide (LPS) and the heat-killed gram-negative bacteria, Escherischia coli and Aeromonas...
149.
Stress-induced extracellular Hsp72 is a functionally significant danger signal to the immune system - Campisi, Jay; Leem, Ted H.; Fleshner, Monika
Extracellular heat-shock proteins (eHsp) such as those belonging to the 70-kDa family of Hsp (eg, Hsp72) have been hypothesized to act as a danger signal to immune cells, promote immune responses, and improve host defense. The current study tested this hypothesis. Adult male F344 rats were exposed to an acute laboratory stressor (100, 5-second, 1.6-mA inescapable tail shocks) and challenged with Escherichia coli. The number of colony-forming units (CFU) of bacteria at the site of injection, the levels of eHsp72, the immune response to eHsp72 and E coliderived lipopolysaccharide (LPS), and the amount of time required to recover from in...
150.
Expression differences in mitochondrial and secretory chaperonin 60 (Cpn60) in pancreatic acinar cells - Li, Y.; Gingras, D.; Londoño, I.; Bendayan, M.
In pancreatic acinar cells, chaperonin Cpn60 is present in all the cellular compartments involved in protein secretion as well as in mitochondria. To better understand the role Cpn60 plays in pancreatic secretion, we have evaluated its changes under experimental conditions known to alter pancreatic secretion. Quantitative protein Agold immunocytochemistry was used to reveal Cpn60 in pancreatic acinar cells. Cpn60 immunolabelings in cellular compartments involved in secretion were found to decrease in acute pancreatitis as well as upon stimulation of secretion and in starvation conditions. A major increase in Cpn60 was recorded in diabetic condition. This was normalized by insulin treatment....
152.
Overexpression of heat shock proteins differentially modulates protein kinase C expression in rat neonatal cardiomyocytes - Coaxum, Sonya D.; Martin, Jody L.; Mestril, Ruben
Previous studies have suggested that protein kinase C (PKC) is involved in heat shock protein (Hsp)mediated cardioprotection. Therefore, we wanted to determine whether overexpression of Hsps modulates PKC expression, which will give us further insight into understanding the mechanism by which Hsps and PKC interact to protect cells from stress-induced injury. Specifically, we overexpressed the inducible form of Hsp70 (Hsp70i) or Hsp90 in rat neonatal cardiomyocytes and evaluated PKC? or PKC? expression by immunoblotting and immunofluorescent confocal microscopy. Western analysis showed that overexpression of Hsp70i or Hsp90 decreased PKC? expression. However, overexpression of Hsp70i or Hsp90 did not modify PKC?...
153.
CHIP: a link between the chaperone and proteasome systems - McDonough, Holly; Patterson, Cam
CHIP, carboxy terminus of Hsc70 interacting protein, is a cytoplasmic protein whose amino acid sequence is highly conserved across species. It is most highly expressed in cardiac and skeletal muscle and brain. The primary amino acid sequence is characterized by 3 domains, a tetratricopeptide repeat (TPR) domain at its amino terminus, a U-box domain at its carboxy terminus, and an intervening charged domain. CHIP interacts with the molecular chaperones Hsc70-Hsp70 and Hsp90 through its TPR domain, whereas its U-box domain contains its E3 ubiquitin ligase activity. Its interaction with these molecular chaperones results in client substrate ubiquitylation and degradation by...
154.
Mechanisms for regulation of Hsp70 function by Hsp40 - Fan, Chun-Yang; Lee, Soojin; Cyr, Douglas M.
The Hsp70 family members play an essential role in cellular protein metabolism by acting as polypeptide-binding and release factors that interact with nonnative regions of proteins at different stages of their life cycles. Hsp40 cochaperone proteins regulate complex formation between Hsp70 and client proteins. Herein, literature is reviewed that describes the mechanisms by which Hsp40 proteins interact with Hsp70 to specify its cellular functions.
155.
Molecular characterization of genes encoding cytosolic Hsp70s in the zygomycete fungus Rhizopus nigricans - ?ernila, Botjan; ?renar, Bronislava; Breskvar, Katja
Previous studies have shown that some stressors, including steroid hormones 21-OH progesterone and testosterone, stimulate the accumulation of heat shock protein 70 (hsp70) messenger ribonucleic acid (mRNA) population in the zygomycete filamentous fungus Rhizopus nigricans. In this study we report the cloning of 3 R nigricans hsp70 genes (Rnhsp70-1, Rnhsp70-2, and Rnhsp70-3) encoding cytosolic Hsp70s. With a Southern blot experiment under high stringency conditions we did not detect any additional highly homologous copies of the cytosolic hsp70 genes in the R nigricans genome. Sequence analyses showed that all 3 genes contain introns within the open reading frame. The dynamics of...
156.
Expression of heat shock protein 32 (hemoxygenase-1) in the normal and inflamed human stomach and colon: an immunohistochemical study - Barton, S.G.R.G.; Rampton, D.S.; Winrow, V.R.; Domizio, P.; Feakins, R.M.
Heat shock protein 32 (Hsp32, hemoxygenase-1) is induced by reactive oxygen metabolites (ROM) and degrades heme leading to the formation of antioxidant bilirubin. Increased mucosal generation of ROM occurs in gastritis and inflammatory bowel disease. We aimed to assess mucosal expression of Hsp32 in normal stomach and colon and to test the hypothesis that disease-related differential expression occurs in inflamed tissue. Gastric body and antral mucosal biopsies were obtained from 33 patients comprising Helicobacter pylorinegative normal controls (n = 8), H pylorinegative gastritis patients (n = 11), and H pyloripositive gastritis patients (n = 14). Forty-seven archival colonic mucosal biopsies...
157.
Heat shock protein 70 or heat shock protein 27 overexpressed in human endothelial cells during posthypoxic reoxygenation can protect from delayed apoptosis - Kabakov, Alexander E.; Budagova, Karina R.; Bryantsev, Anton L.; Latchman, David S.
Overexpression of heat shock protein (Hsp) 70 and Hsp27 in vivo was proclaimed as a potential tool in therapy of ischemia-reperfusion injury. However, it was so far not known whether these Hsps can beneficially act when increased in cells just at the stage of postischemic reperfusion. This issue was examined in a model of ischemia-reperfusion stress when cultures of endothelial cells (EC) from human umbilical vein were infected with virus-based vectors expressing Hsp70 or Hsp27, or Hsp56, or green fluorescent protein (GFP) and exposed to 20 hours of hypoxia followed by reoxygenation. The infection was performed either 10 hours before...
158.
Heat shock protein 70-reactivity is associated with increased cell surface density of CD94/CD56 on primary natural killer cells - Gross, Catharina; Schmidt-Wolf, Ingo G.H.; Nagaraj, Srinivas; Gastpar, Robert; Ellwart, Joachim; Kunz-Schughart, Leoni A.; Multhoff, Gabriele
Previously we described an involvement of the C-type lectin receptor CD94 and the neuronal adhesion molecule CD56 in the interaction of natural killer (NK) cells with Hsp70-protein and Hsp70-peptide TKD. Therefore, differences in the cell surface density of these NK cellspecific markers were investigated comparatively in CD94-sorted, primary NK cells and in established NK cell lines NK-92, NKL, and YT after TKD stimulation. Initially, all NK cell types were positive for CD94; the CD56 expression varied. After stimulation with TKD, the mean fluorescence intensity (mfi) of CD94 and CD56 was upregulated selectively in primary NK cells but not in NK...
159.
Deoxyribonucleic acid damage induced by doxorubicin in peripheral blood mononuclear cells: possible roles for the stress response and the deoxyribonucleic acid repair process - Nadin, Silvina B.; Vargas-Roig, Laura M.; Cuello-Carrión, F. Darío; Ciocca, Daniel R.
Doxorubicin is an antineoplastic drug widely used in cancer treatment. However, many tumors are intrinsically resistant to the drug or show drug resistance after an initial period of response. Among the different molecules implicated with doxorubicin resistance are the heat shock proteins (Hsps). At present we do not know with certainty the mechanism(s) involved in such resistance. In the present study, to advance our knowledge on the relationship between Hsps and drug resistance, we have used peripheral blood mononuclear cells obtained from healthy nonsmoker donors to evaluate the capacity of a preliminary heat shock to elicit the Hsp response and...
160.
Progression of arteriovenous bypass restenosis in mice exposed to a 50 Hz magnetic field - Henderson, Blair; Tagwerker, Andrea; Mayerl, Christina; Pfister, Gerald; Boeck, Günther; Ulmer, Hanno; Dietrich, Hermann; Wick, Georg
The controversy over whether magnetic fields (MF) produced by electrical wiring and appliances contribute to diseases such as cancer has been debated in the literature for more than 2 decades. These extremely low frequency fields at 50 or 60 Hz are omnipresent in the industrialized world and have been linked to various forms of cancer by epidemiological studies. Little has been published investigating any possible role of MF and cardiovascular disease, and this is the first study looking specifically at the effect of exposure to high-intensity MF on the development and progression of restenosis. A mouse arteriovenous bypass model was...
141.
