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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We recently reported that lipopolysaccharide (LPS) induces apoptosis in cultured sheep pulmonary artery endothelial cells (SPAEC). Information about survival signals against this and other stimuli for endothelial cell apoptosis is limited to factors in the extracellular space. In other cell types, apoptosis is also affected by intracellular gene products. The heat-shock response is a highly conserved cellular stress response affording cytoprotection against a variety of cytotoxic conditions. Accordingly, we tested the hypothesis that prior induction of the heat-shock response would affect apoptosis in cultured SPAEC. Exposure of SPAEC to either heat (43 degrees C, 90 min) or sodium arsenite (100 microM, 90 min) induced expression of heat-shock protein-70 (HSP-70). LPS (0.1 microg/ml) treatment of SPAEC induced apoptotic morphology, cell detachment, high molecular weight (> 30 kb) DNA fragmentation, and internucleosomal DNA fragmentation. Prior induction of the heat-shock response attenuated LPS-mediated apoptosis, a protective event associated with a concomitant attenuation of rapid (within minutes) LPS-stimulated superoxide anion (O2.-) generation. Subsequent experiments involving transient overexpression of HSP-70, by direct gene transfer, suggest a direct role for HSP-70 in the attenuation of LPS-mediated apoptosis. We conclude that the heat-shock response is an intracellular survival signal against LPS-mediated apoptosis, and that the protective mechanism may involve HSP-70 directly, as well as inhibition of LPS-mediated O2.- generation.
Am J Respir Cell Mol Biol 1996 Dec
PMID:The heat-shock response attenuates lipopolysaccharide-mediated apoptosis in cultured sheep pulmonary artery endothelial cells. 896 69

Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) large subunit (LS) epsilon N-methyltransferase (Rubisco LSMT) catalyzes the posttranslational methylation of the epsilon-amino group of Lys-14 in the LS of Rubisco in many higher plant species including tobacco. The tobacco Rubisco LSMT gene (rbcMT-T) and its cDNA were isolated, sequenced, and characterized. The gene contains 6 exons and spans about 6 kb. Primer extension analysis indicated one transcription start site located 93 nt upstream of the translation initiation site. Sequence analysis of the 5'-flanking region suggests several potential binding sites for transcription factors, including 7 GT-1 elements and an HSP-70.5 element. Gene dosage analysis by Southern hybridization demonstrated that the tobacco rbcMT-T gene is present as a single copy in the tobacco haploid genome. The full-length cDNA for tobacco rbcMT-T is 1974 nt in length excluding the 3' poly(A)15 tail, and encodes a 491 amino acid polypeptide with a molecular mass of ca. 56kDa. The deduced amino acid sequence of tobacco Rubisco LSMT has 64.5% identity and 75.3% similarity with the sequence of pea Rubisco LSMT, and both proteins contain several copies of a conserved imperfect leucine-rich repeat motif.
Plant Mol Biol 1996 Nov
PMID:Organization and characterization of the ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit epsilon N-methyltransferase gene in tobacco. 898 May 18

Two groups of rats (n = 5) weighing 175-185 g were implanted (sc) with osmotic minipumps to deliver (0.5 microliter/hr) deionized water or cadmium chloride (CdCl2; 0.2 M) for 14 days. On completion of subacute treatment, liver and kidneys were collected from control and CdCl2 treated groups for analysis. We report that, subacute exposure to CdCl2 results in significant Cd accumulation in liver and kidneys, and heat-shock-protein 72 (HSP-72) induction in the liver. Results affirm a role for liver HSP-72 in Cd-toxicity.
Res Commun Mol Pathol Pharmacol 1996 Nov
PMID:Subacute exposure to cadmium chloride induces HSP-72 in rat liver. 898 20

Stress-induced regulation of the 72 kD heat shock protein (HSP 72), the major stress inducible protein in mammalian cells, is mediated by the activation and binding of a heat shock transcription factor (HSF) to a specific sequence in the 5' region of the promoter termed the heat shock element (HSE). In agreement with this regulation, HSP 72 is absent in most cells under unstressed conditions but is rapidly synthesized following exposure to protein damaging stressors. An exception is the skeletal muscle, where HSP 72 is constitutively expressed in muscles that express the beta myosin heavy chain (beta-MHC) protein. Since beta-MHC is also expressed in the ventricles of large mammals, we have examined if HSP 72 was also constitutively expressed in beta-MHC positive hearts. Chambers of the heart muscle from Yorkshire swine were examined for alpha-MHC, beta-MHC and HSP 72 content. HSF:HSE activation was also assessed by gel shift analyses. In the swine heart, atria and ventricles differed in their alpha-MHC and beta-MHC protein content but all expressed a high HSP 72 content. Gel shift analyses demonstrated no HSF:HSE binding in extracts from unstressed swine hearts. These results indicate that HSP 72 is constitutively expressed in all portions of the swine heart and this expression may not be dependent on an HSF:HSE interaction.
J Mol Cell Cardiol 1996 Mar
PMID:Constitutive expression of HSP 72 in swine heart. 901 30

Thermotolerant cells display attenuated heat shock protein 70 kD (HSP-70) gene expression and signal transduction such as intracellular Ca2+ concentration and inositol trisphosphate in response to sublethal heat. To further investigate the regulation of heat shock gene expression, we developed constructs containing human HSP-70 and HSF1 genes and transfected human epidermoid A-431 cells. These cells were chosen because skin cells are especially vulnerable to heat shock and other environmental stressors. We report that A431 cells can be successfully transfected with HSP-70 and HSF1 genes as shown by the elevated levels of respective message and protein. Overexpression of HSP-70 in cells transfected with HSP-70 gene led to a down-regulation of the HSF1 gene expression. Interestingly, transfection of cells with the HSF1 gene was not associated with increased expression of HSP-70. Exposure of HSF1 gene-transfected cells to heat resulted in a transient but significant increase in HSP-70 gene expression as compared to that found in vector-transfected cells, which was completely inhibited by treatment with staurosporine. In conclusion, we have demonstrated successful transfection of human A-431 cells with HSF1 and HSP-70 genes, where the regulation of their expression can be studied.
Mol Cell Biochem 1997 Feb
PMID:Heat shock gene-expression in HSP-70 and HSF1 gene-transfected human epidermoid A-431 cells. 905 91

During the pre-implantation phase of development, the mouse embryo synthesizes HSC70, and HSP90 alpha and beta at a very high rate. After implantation, the expression of HSPs appears non-coordinated and is not uniform in the different tissues. The expression of inducible HSPs appears later in development than that of constitutive members of the family. HSP25 is highly expressed early in heart and muscle development, but also in some structure of the central nervous system. HSC70 and HSP90 beta are expressed ubiquitously, but their expression reaches very high levels in the nervous system (neural tracks) and during bone morphogenesis (in the hypertrophic chondrocytes). The mechanisms involved in HSP expression during mouse embryogenesis are probably diverse, involving tissue-specific sequences. Although the DNA-binding activity and expression of the second heat shock transcription factor, HSF2, seems to be developmentally regulated, becoming detectable at the blastocyst stage and reaching a peak at day 10 of development, there is no obvious correlation between the level of this factor and the expression of HSPs. HSF2 might be involved in the onset of expression of HSPs, regulate (inhibit) their expression, or control the expression of other developmental genes yet to be discovered.
Cell Mol Life Sci 1997 Feb
PMID:HSP gene expression and HSF2 in mouse development. 911 6

We have investigated the early development expressional of the heat shock protein genes (hsps) and HSP synthesis and their role during neuroectoderm induction, differentiation and early CNS formation. The expression and kinetics of 90, 73/71, 47 and 27 HSPs on neuroectoderm differentiation was compared under normal and stressed conditions. The role of HSPs on neuroctoderm cell fate including thermotolerance and apoptosis using a whole in vitro embryo culture system was studied. Hsp expression appears closely linked in early mammalian development to critical differentiation and proliferation stages in early brain and heart formation. The hsps are developmentally activated around blastula stage and HSPs are constitutively expressed at high levels during neural tube closure and are heat shock responsive. Using both Northern analysis, confocal microscopy and whole mount in situ hybridisation we have identified the mRNA hsp transcripts and HSPs during organogenesis. HSPs were detected during neuroectoderm cell induction and differentiation with the hsp mRNA being tightly regulated during the cell cycle of neuroectoderm especially at early fore-, mid-, hindbrain and heart formation. The 'chaperone' functions of the HSPs are well known, recently during gastrulation the HSP47 and 27 have been shown to specifically bind and fold to nascent collagen and actin molecules respectively. This role is essential for the formation of the basement membrane, extra cellular matrix and neural crest migration during neural plate development. HSP function was observed by using anti-sense strategy, short '5 anti-sense cDNA' hsp oligonucleotides inhibited hsp expression during gastrulation in the whole embryo cultures. The developmental activation of the heat shock element (HSE) is essential to our understanding of the HSPs role in neuronal cell fate. Using specific polyclonal antibodies to HSF1 and 2 (Dr Nakai, Kyoto University) the expression of heat shock factors (HSFs) during neuroectoderm differentiation was examined. Using Western analysis, confocal microscopy and flow cytometry HSF1 and 2 were identified and studied under both normal and heat shocked conditions. During gastrulation higher levels of HSF1 and 2 were identified in the neuroectoderm layer especially in regions of the fore-, mid- and hindbrain. The heat shock response and activation of the HSPs 90, 70, 47 and 27 families have been correlated with HSF1 and 2. The HSF1 appears to be present in all early embryonic cells but appears not to bind to the HSE until early head fold stage at gastrulation when the presence of HSF2 is observed. During neuroectoderm differentiation the activation of HSF1 and 2 appears to correlate with high constitutive expression of many of the hsps specifically hsp90, 73, 71, 47 and 27 being tightly regulated by the cell cycle at neurulation.
Cell Mol Life Sci 1997 Feb
PMID:Heat shock and the role of the HSPs during neural plate induction in early mammalian CNS and brain development. 911 8

Acid proteinases of C6 rat glioma cells were analyzed by means of gelatine polyacrylamide electrophoresis with respect to their responses to stress (heat shock and butanol). Proteinase activities on gelatine gels were characterized by their molecular masses. pH-optima, isoelectric points and reactions to inhibitors. Four bands of 25, 35 and 65/85 kDa most probably represent active and proforms as well as precursor complexes of lysosomal cysteine proteinases with pH optima between 4.0 and 5.0. The 25-kDa band seems to contain cathepsin L and B, the 35-kDa band proforms of cathepsin L and B and the 65/85-kDa bands possibly precursor complexes of cathepsin L and B. After 30-min heat shocks of different temperatures (40-50 degrees C), the 35-kDa activity increased, whereas the 65/85-kDa activity decreased after exposure to 42 and 44 degrees C, which also caused a strong increase in the level of the inducible heat shock protein of 68 kDa (HSP 68). The alterations of the proteinase activities and the increases of the HSP 68 levels occur at heat shock treatments that cause cell death in about 25-40% of the population as determined by Trypan blue staining. HSP 68 induction and proteinase activity changes were also observed 12 hr after a 1-hr treatment with different butanol concentrations (0.14-0.16 M). Kinetics of the response to a 30-min heat shock (44 degrees C) revealed a maximal decrease of the 35-kDa and a maximal increase of the 65/85-kDa activities after 12 hr recovery. When cells were exposed to repeated heat shocks (44 degrees C) at 12-hr intervals, the HSP 68 level further increased, whereas the 35-kDa and 65/85-kDa proteinase activities did not change. This result indicates a role of HSP 68 (or other HSPs) in the processing or stability of the putative cathepsin precursors (65/85-kDa complexes).
Comp Biochem Physiol B Biochem Mol Biol 1997 Jun
PMID:Stress response of lysosomal cysteine proteinases in rat C6 glioma cells. 922 78

We tested the hypothesis that heat-shock protected myocardial Ca2+-cycling by sarcoplasmic reticulum from ischemia and reperfusion (I/R) injury. Twenty-four hours after increasing body temperature to 42 degrees C for 15 min, rat hearts were isolated, Langendorff-perfused, and subjected to 30 min ischemia then 30 min reperfusion. Left ventricles were homogenized and their ionized Ca2+ concentration monitored with indo- during Ca2+-uptake in the presence and absence of the Ca2+-release channel (CRC) modulator ryanodine. Tissue content of heat-shock protein 72 (HSP 72) was analyzed. Exposure to I/R resulted in a 37% enhancement of CRC activity but no effect on Ca2+-pumping activity, resulting in 25% decreased net Ca2+-uptake activity. Pre-exposure to heat-shock resulted in a 10-fold increase in HSP 72, and a 25% enhancement of maximal Ca2+-pumping activity which counteracted the effect of I/R on CRC and net Ca2+-uptake activities. This protection of SR Ca2+-cycling was associated with partial protection of myocardial physiological performance. Net Ca2+-uptake activity was correlated with the left ventricular developed pressure and its rate of change. We conclude that one of the mechanisms by which heat-shock protects myocardium from I/R injury is to upregulate SR Ca2+-pumping activity to counteract the enhanced SR Ca2+-release produced by I/R.
Mol Cell Biochem 1997 Aug
PMID:Compensatory up-regulation of cardiac SR Ca2+-pump by heat-shock counteracts SR Ca2+-channel activation by ischemia/reperfusion. 927 64

Chemicals and conditions that damage proteins, promote protein misfolding, or inhibit protein processing trigger the onset of protective homeostatic mechanisms resulting in "stress responses" in mammalian cells. Included in these responses are an acute inhibition of mRNA translation at the initiation step, a subsequent induction of various protein chaperones, and the recovery of mRNA translation. Separate, but closely related, stress response systems exist for the endoplasmic reticulum (ER), relating to the induction of specific "glucose-regulated proteins" (GRPs), and for the cytoplasm, pertaining to the induction of the "heat shock proteins" (HSPs). Activators of the ER stress response system, including Ca(2+)-mobilizing and thiol-reducing agents, are discussed and compared to activators of the cytoplasmic stress system, such as arsenite, heavy metal cations, and oxidants. An emerging integrative literature is reviewed that relates protein chaperones associated with cellular stress response systems to the coordinate regulation of translational initiation and protein processing. Background information is presented describing the roles of protein chaperones in the ER and cytoplasmic stress response systems and the relationships of chaperones and protein processing to the regulation of mRNA translation. The role of chaperones in regulating eIF-2 alpha kinase activities, eIF-2 cycling, and ribosomal loading on mRNA is emphasized. The putative role of GRP78 in coupling rates of translation to processing is modeled, and functional relationships between the HSP and GRP chaperone systems are discussed.
Prog Nucleic Acid Res Mol Biol 1998
PMID:Regulation of translational initiation during cellular responses to stress. 930 64


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