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 81 - 100 de 951
81.
Differential accumulation of U14 snoRNA and hsc70 mRNA in Chinese hamster cells after exposure to various stress conditions - Chen, Ming-Shun; Goswami, Prabhat C.; Laszlo, Andrei
We have previously characterized the unique organization of the U14 small nucleolar ribonucleic acid (snoRNA) gene in Chinese hamster HA-1 cells. The single copy of the hsc70/U14 gene is the only source for the production of both U14 snoRNA species and hsc70 messenger ribonucleic acid (mRNA) in these cells. Here we report that the accumulations of U14 snoRNA and hsc70 mRNA are different in response to various stress conditions, although both of them are transcribed in a single primary transcript. Heat shock induced an increased accumulation of both U14 snoRNA and hsc70 mRNA. On the other hand, exposure to sodium...
82.
The effect of hyperthermia on the induction of cell death in brain, testis, and thymus of the adult and developing rat - Khan, Vania R.; Brown, Ian R.
Stressful stimuli can elicit 2 distinct reactive cellular responses, the heat shock (stress) response and the activation of cell death pathways. Most studies on the effects of hyperthermia on the mammalian nervous system have focused on the heat shock response, characterized by the transient induction of Hsps, which play roles in repair and protective mechanisms. This study examines the effect of hyperthermia on the induction of cell death via apoptosis, assayed by terminal deoxynucleotidyl transferasemediated deoxyuridine triphosphate nick-end labeling and active caspase 3 cytochemistry, in the adult rat brain, testis, and thymus. Results show that a fever-like increase in temperature...
83.
Hsp90, not Grp94, regulates the intracellular trafficking and stability of nascent ErbB2 - Xu, Wanping; Mimnaugh, Edward G.; Kim, Jung-Sik; Trepel, Jane B.; Neckers, Leonard M.
The benzoquinone ansamycin geldanamycin (GA) stimulates proteasome-mediated degradation of plasma membraneassociated ErbB2, a receptor tyrosine kinase. Drug sensitivity is mediated by ErbB2's kinase domain and occurs subsequent to the disruption of Hsp90 interaction with this domain. Full-length ErbB2 is efficiently processed via the endoplasmic reticulum (ER) and Golgi network, so that at steady state most of the detectable protein is plasma membrane associated. However, previous studies have also demonstrated the GA sensitivity of newly synthesized ErbB2, normally a minor component of the total cellular pool of the kinase. Drug sensitivity of nascent ErbB2 is distinguished by 2 characteristicsprotein instability and...
84.
Thermal acclimation and stress in the American lobster, Homarus americanus: equivalent temperature shifts elicit unique gene expression patterns for molecular chaperones and polyubiquitin - Spees, Jeffrey L.; Chang, Sharon A.; Snyder, Mark J.; Chang, Ernest S.
Using homologous molecular probes, we examined the influence of equivalent temperature shifts on the in vivo expression of genes coding for a constitutive heat shock protein (Hsc70), heat shock proteins (Hsps) (Hsp70 and Hsp90), and polyubiquitin, after acclimation in the American lobster, Homarus americanus. We acclimated sibling, intermolt, juvenile male lobsters to thermal regimes experienced during overwintering conditions (0.4 ± 0.3°C), and to ambient Pacific Ocean temperatures (13.6 ± 1.2°C), for 45 weeks. Both groups were subjected to an acute thermal stress of 13.0°C, a temperature shift previously found to elicit a robust heat shock response in ambient-acclimated lobsters. Animals...
87.
Rhizobium leguminosarum chaperonin 60.3, but not chaperonin 60.1, induces cytokine production by human monocytes: activity is dependent on interaction with cell surface CD14 - Lewthwaite, Jo; George, Roger; Lund, Peter A.; Poole, Steve; Tormay, Peter; Sharp, Lindsay; Coates, Anthony R.M.; Henderson, Brian
As part of a program of work to understand the interaction of bacterial chaperonins with human leukocytes, we have examined 2 of the 3 chaperonin 60 (Cpn 60) gene products of the nonpathogenic plant symbiotic bacterium, Rhizobium leguminosarum, for their capacity to induce the production of pro- and antiinflammatory cytokines by human cells. Recombinant R. leguminosarum Cpn 60.1 and 60.3 proteins were added to human monocytes at a range of concentrations, and cytokine production was measured by sandwich enzyme-linked immunosorbent assay. In spite of the fact that the 2 R. leguminosarum Cpn 60 proteins share 74.5% amino acid sequence identity,...
88.
Hsp72 expression enhances survival in adenosine triphosphatedepleted renal epithelial cells - Wang, Y.-H.; Knowlton, A.A.; Li, F.-H.; Borkan, S.C.
Although prior heat stress (HS) inhibits apoptosis in adenosine phosphate (ATP)-depleted renal epithelial cells (REC), the specific stress protein(s) responsible for cytoprotection have not been identified. The present study evaluated the hypothesis that Hsp72, the major inducible member of the Hsp70 family, protects REC against ATP depletion injury. In the presence of isopropyl-?-d-thiogalactoside (IPTG), a stable line of transfected opossum kidney cells was induced to overexpress human Hsp72 tagged with the flag epitope. Transfected cells from 2 clones that expressed Hsp72 at a level comparable with wild-type cells were subjected to transient heat stress (43°C for 1 hour). To assess...
89.
Distribution, phosphorylation, and activities of Hsp25 in heat-stressed H9c2 myoblasts: a functional link to cytoprotection - Bryantsev, Anton L.; Loktionova, Svetlana A.; Ilyinskaya, Olga P.; Tararak, Eduard M.; Kampinga, Harm H.; Kabakov, Alexander E.
The behavior of the endogenous heat shock protein 25 (Hsp25) in heat-stressed rat H9c2 myoblasts was studied. After mild or severe heating, this protein became less extractable with Triton X-100 and displayed characteristic immunofluorescence patterns, namely (1) granules in the nucleus, and (2) association with F-actin bundles in the cytoplasm. The intranuclear granulation of Hsp25 and its association with F-actin were sensitive to drugs affecting Hsp25 phosphorylation (cantharidin, sodium orthovanadate, SB203580, SB202190). Isoform analysis of Hsp25 translocated to the nucleus-free cytoskeletal fraction revealed only mono- and biphosphorylated Hsp25 and no unphosphorylated Hsp25. Transfected luciferase with initial localization in the nucleosol...
90.
Characterization and functional analysis of a heart-enriched DnaJ/Hsp40 homolog dj4/DjA4 - Abdul, Khaleque Md.; Terada, Kazutoyo; Gotoh, Tomomi; Hafizur, Rahman Md.; Mori, Masataka
DnaJ homologs are cochaperones of the heat shock protein 70 (hsp70) family. Homologs dj1 (hsp40/hdj-1/DjB1), dj2 (HSDJ/hdj-2/rdj-1/DjA1), and dj3 (cpr3/DNAJ3/HIRIP4/rdj2/DjA2) have been identified in the mammalian cytosol and characterized. In this paper we characterized newly found dj4 (DjA4) and compared it with other chaperones. The dj4 messenger ribonucleic acid (mRNA) and protein were expressed strongly in heart and testis, moderately in brain and ovary, and weakly in other tissues in mice. Dj4 constituted about 1% of the total protein in heart. Testis gave extraspecies of dj4 mRNA and protein in addition to those seen in other tissues. On subcellular fractionation...
91.
Actin cytoskeleton and small heat shock proteins: how do they interact? - Mounier, Nicole; Arrigo, André-Patrick
Actin and small heat shock proteins (sHsps) are ubiquitous and multifaceted proteins that exist in 2 reversible forms, monomers and multimers, ie, the microfilament of the cytoskeleton and oligomers of the sHsps, generally, supposed to be in a spherical and hollow form. Two situations are described in the literature, where the properties of actin are modulated by sHsps; the actin polymerization is inhibited in vitro by some sHsps acting as capping proteins, and the actin cytoskeleton is protected by some sHsps against the disruption induced by various stressful conditions. We propose that a direct actin-sHsp interaction occurs to inhibit actin...
92.
Overexpression of Hsp27 affects the metastatic phenotype of human melanoma cells in vitro - Aldrian, Silke; Trautinger, Franz; Fröhlich, Ilse; Berger, Walter; Micksche, Michael; Kindas-Mügge, Ingela
Overexpression of the small heat shock protein Hsp27 has been shown by us to inhibit the in vitro proliferation rate and to delay tumor development of a human melanoma cell line (A375) in nude mice. We hypothesized that Hsp27 may influence the neoplastic phenotype. In the present study Hsp27 transfectants from this cell line were analyzed for various cellular aspects associated with the metastatic process. We found that Hsp27-overexpressing clones exhibited an altered cellular morphology as compared with control transfected cells. The Hsp27-positive cells tended to develop an epithelial-like phenotype growing in clusters and were characterized by a loss of...
93.
?Chaperones come of age - Söti, Csaba; Csermely, Péter
Chaperone function plays a key role in repairing proteotoxic damage, in the maintenance of cell architecture, and in cell survival. Here, we summarize our current knowledge about changes in chaperone expression and function in the aging process, as well as their involvement in longevity and cellular senescence.
94.
?The heat shock response and cytoprotection of the intestinal epithelium - Malago, Joshua J.; Koninkx, Jos F.J.G.; van Dijk, Jaap E.
Following heat stress, the mammalian intestinal epithelial cells respond by producing heat shock proteins that confer protection under stressful conditions, which would otherwise lead to cell damage or death. Some of the noxious processes against which the heat shock response protects cells include heat stress, infection, and inflammation. The mechanisms of heat shock responseinduced cytoprotection involve inhibition of proinflammatory cytokine production and induction of cellular proliferation for restitution of the damaged epithelium. This can mean selective interference of pathways, such as nuclear factor kappa B (NF-?B) and mitogen-activated protein kinase (MAPK), that mediate cytokine production and growth responses. Insight into...
95.
?Activation of the mitogen-activated protein kinase pathways by heat shock - Dorion, Sonia; Landry, Jacques
In addition to inducing new transcriptional activities that lead within a few hours to the accumulation of heat shock proteins (Hsps), heat shock activates within minutes the major signaling transduction pathways involving mitogen-activated protein kinases, extracellular signalregulated kinase, stress-activated protein kinase 1 (SAPK1)c-Jun N-terminal kinase, and SAPK2-p38. These kinases are involved in both survival and death pathways in response to other stresses and may, therefore, contribute significantly to the heat shock response. In the case of p38, the activation leads to the phosphorylation and activation of one of the Hsps, Hsp27. Phosphorylation occurs very early during stress, is tightly regulated,...
96.
?Growing old with nuclear factor?B - Giardina, Charles; Hubbard, Andrea K.
The transcription factor nuclear factor?B (NF-?B) is involved in the regulation of a broad spectrum of genes that play important roles in a myriad of physiological and pathological events ranging from the immune response to carcinogenesis. Interestingly, many processes in which NF-?B plays a central role have long been noted for their alteration with age. A number of research groups have reported rather dramatic changes in NF-?B activity as humans and animals age, with tissue-specific increases and decreases in NF-?B activity being reported. The extent to which changes in NF-?B activity drive aging and influence life span in humans and...
97.
?Visibly stressed: the role of eIF2, TIA-1, and stress granules in protein translation - Anderson, Paul; Kedersha, Nancy
Eukaryotic cells express a family of eukaryotic translation initiation factor 2 alpha (eIF2?) kinases (eg, PKR, PERK-PEK, GCN2, HRI) that are individually activated in response to distinct types of environmental stress. Phosphorylation of eIF2? by one or more of these kinases reduces the concentration of eIF2guanosine triphosphate (GTP)transfer ribonucleic acid for methionine (tRNAMet), the ternary complex that loads tRNAMet onto the small ribosomal subunit to initiate protein translation. When ternary complex levels are reduced, the related RNA-binding proteins TIA-1 and TIAR promote the assembly of a noncanonical preinitiation complex that lacks eIF2-GTP-tRNAMet. The TIA proteins dynamically sort these translationally incompetent...
98.
?The mammalian endoplasmic reticulum as a sensor for cellular stress - Ma, Yanjun; Hendershot, Linda M.
The recent elucidation of the mammalian unfolded protein response pathway has revealed a unique and transcriptionally complex signal transduction pathway that protects cells from a variety of physical and biochemical stresses that can occur during normal development and in disease states. Although the stress conditions are monitored in the endoplasmic reticulum, the beneficial effects of this pathway are extended to other cellular organelles and to the organism itself.
100.
Eukaryotic chaperonin containing T-complex polypeptide 1 interacts with filamentous actin and reduces the initial rate of actin polymerization in vitro - Grantham, Julie; Ruddock, Lloyd W.; Roobol, Anne; Carden, Martin J.
We have previously observed that subunits of the chaperonin required for actin production (type-II chaperonin containing T-complex polypeptide 1 [CCT]) localize at sites of microfilament assembly. In this article we extend this observation by showing that substantially substoichiometric CCT reduces the initial rate of pyrene-labeled actin polymerization in vitro where eubacterial chaperonin GroEL had no such effect. CCT subunits bound selectively to F-actin in cosedimentation assays, and CCT reduced elongation rates from both purified actin filament seeds and the short and stabilized, minus-end blocked filaments in erythrocyte membrane cytoskeletons. These observations suggest CCT might remain involved in biogenesis of the...
81.
