Heat Shock (45°C) Results in an Increase of Nuclear Matrix Protein Mass in HeLa Cells

Warters, Raymond L.; Brizgys, Lucy M.; Sharma, Rajesh; Roti, Joseph L. Roti

doi:10.1080/09553008614550641

Cited by 60 publications

(25 citation statements)

References 27 publications

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“…Thermal denaturation of (nuclear) proteins resulting in aggregation of usually soluble nuclear proteins (see Kampinga, 1993, for review) with the (insoluble) nuclear matrix was found to correlate with the inhibitory effect of heat on m-AMSA toxicity (Kampinga et al, 1989a). This aggregation also was found to be related to altered DNA-matrix attachment interactions (Warters et al, 1986;Sakkers et al, submitted). In HeLa S3 cells, the initial aggregation is the same in thermotolerant cells as in non-tolerant cells (Kampinga et al, 1987(Kampinga et al, , 1989c, consistent with the observation that thermal protection against drug toxicity and break formation is about the same in thermotolerant and non-tolerant cells (Figures 4 and 5).…”

Section: Resultsmentioning

confidence: 97%

Hyperthermia, thermotolerance and topoisomerase II inhibitors

Kampinga

1995

Br J Cancer

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Summary The cytoxicity of both intercalating (m-AMSA) and non-intercalating (VP16, VM26) topoisomerase II-targeting drugs is thought to occur via trapping DNA topoisomerase II on DNA in the form of cleavable complexes. First, analysis of cleavable complexes (detected as DNA double-strand breaks) by pulsed-field gel electrophoresis confirmed the correlation between cleavable complex formation and cytotoxicity of three topoisomerase-targeting drugs in HeLa S3 cells (the order of effects being VM26> m-AMSA>VP16). In contrast to many antineoplastic agents, hyperthermic treatments were found to protect cells against the toxicity of all three topoisomerase II drugs. Hyperthermia treatment does not alter drug accumulation but reduces the ability of the drug-topoisomerase II complex to form the cleavable complexes. Nuclear protein aggregation induced by heat at the sites of topoisomerase II-DNA interaction may explain such an effect. In thermotolerant cells, the toxic effects of VP16 but not m-AMSA were reduced. For both drugs, however, the status of thermotolerance did not affect cleavable complex formation by the drugs. Thus, protection against VP-16 toxicity seems not to be associated with heat-induced activation of the P-gp 170 pump or altered topoisomerase II-DNA interactions. Rather, a protective (heat shock protein mediated?) mechanism against non-intercalating topoisomerase II drugs seems to occur at a stage after DNA-drug interaction. Finally, heat treatment before topoisomerase II drug treatment reduced toxicity and cleavable complex formation in thermotolerant cells to about the same extent as in non-tolerant cells, consistent with the presumption of nuclear protein aggregation being responsible for this effect.

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Section: Resultsmentioning

confidence: 97%

Hyperthermia, thermotolerance and topoisomerase II inhibitors

Kampinga

1995

Br J Cancer

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“…It is conceivable that the insolubilization and translocation of HSP27 during heat shock simply reflect the protein denaturing effect of heat. A large number of other proteins are similarly insolubilized and associate with nuclear structures during heat shock (13,23,24,33,45,54).…”

Section: Discussionmentioning

confidence: 99%

Modulation of Cellular Thermoresistance and Actin Filament Stability Accompanies Phosphorylation-Induced Changes in the Oligomeric Structure of Heat Shock Protein 27

Lavoie

Lambert

Hickey

et al. 1995

Molecular and Cellular Biology

604

554

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Phosphorylation of heat shock protein 27 (HSP27) can modulate actin filament dynamics in response to growth factors. During heat shock, HSP27 is phosphorylated at the same sites and by the same protein kinase as during mitogenic stimulation. This suggests that the same function of the protein may be activated during growth factor stimulation and the stress response. To determine the role of HSP27 phosphorylation in the heat shock response, several stable Chinese hamster cell lines that constitutively express various levels of the wild-type HSP27 (HU27 cells) or a nonphosphorylatable form of human HSP27 (HU27pm3 cells) were developed. In contrast to HU27 cells, which showed increased survival after heat shock, HU27pm3 cells showed only slightly enhanced survival. Evidence is presented that stabilization of microfilaments is a major target of the protective function of HSP27. In the HU27pm3 cells, the microfilaments were thermosensitized compared with those in the control cells, whereas wild-type HSP27 caused an increased stability of these structures in HU27 cells. HU27 but not HU27pm3 cells were highly resistant to cytochalasin D treatment compared with control cells. Moreover, in cells treated with cytochalasin D, wild-type HSP27 but not the phosphorylated form of HSP27 accelerated the reappearance of actin filaments. The mutations in human HSP27 had no effect on heat shock-induced change in solubility and cellular localization of the protein, indicating that phosphorylation was not involved in these processes. However, induction of HSP27 phosphorylation by stressing agents or mitogens caused a reduction in the multimeric size of the wild-type protein, an effect which was not observed with the mutant protein. We propose that early during stress, phosphorylation-induced conformational changes in the HSP27 oligomers regulate the activity of the protein at the level of microfilament dynamics, resulting in both enhanced stability and accelerated recovery of the filaments. The level of protection provided by HSP27 during heat shock may thus represent the contribution of better maintenance of actin filament integrity to overall cell survival.

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“…Heat-shocked cells present strong alterations of chromatin structures, exhibiting a markedly condensed chromatin (Iliakis and Pantelias 1989;Warters et al 1986), a weaker sensitivity to DNaseI (Pekkala et al 1984) as well as a weaker sensitivity to diffusible mitotic factors (Iliakis and Pantelias 1989). One of the described molecular effects of heat shock on chromatin components is increased histone H1 phosphorylation in vivo (Glover et al 1981).…”

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confidence: 99%

Heat‐shock and related stress enhance RNA polymerase II C‐terminal‐domain kinase activity in HeLa cell extracts

Legagneux

Morange

Bensaude

1990

European Journal of Biochemistry

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Changes in protein kinase activities are thought to contribute to the alteration of gene expression after heat shock and related stresses. In an attempt to identify enzymes which might be involved in both chromatin structure modification and transcriptional switch in heat-shocked cells, we have studied protein kinase activities in heatshocked cell lysates with two exogenous substrates : a tetramer of a heptapeptide (heptapeptide 4) corresponding to the RNA polymerase I1 C-terminal domain (CTD), and the histone H1. Heat-shock and arsenite stress were found to stimulate strongly CTD kinase activity. H1 kinase activity was also stimulated but more weakly. Stimulation of CTD and H1 kinases occurs mainly at the early phase of recovery and by a process which is independent of protein synthesis. The stress-induced H1 kinase is shown to contain a molecule related to the mitotic-promoting factor (MPF) Cdc2 component. On the other hand, though Cdc2-related protein has also been reported to be part of a CTD kinase complex, we show that the stress-induced CTD kinase activity corresponds to a distinct entity. It is proposed that stress activation of CTD kinase might be involved in changing the specificity of RNA polymeiase 11.-Alterations of cellular metabolism by heat shock can be mediated by changes in the activities of protein kinase and protein phosphatase. For example, shut-off by heat shock of most messenger RNA translation, except that of mRNAs coding for heat-shock proteins, is correlated with well-documented changes in the phosphorylation state of ribosomal proteins and initiation factors. Ribosomal protein S6 (Glover 1982; Kennedy et al. 1984;Olsen et al. 1983) and initiation factors elF4B (Duncan and Hershey 1984) and elF4F (Duncan et al. 1987) are dephosphorylated whereas the initiation factor elF2a (Duncan and Hershey 1984) is hyperphosphorylated by heme-controlled repressor kinase in heat-shocked cells or reticulocyte lysates (Bonanou-Tzedaki et al. 1981 ; De Benedetti and Baglioni 1986). Another early effect of heat shock is the shut-off of gene transcription, except that of genes encoding the heat-shock proteins (HSPs) which is specifically stimulated (Lindquist 1986). This specific heat-shock response involves the activation, at least partially by phosphorylation, of a heat-shock gene transcription factor (Sorger and Pelham 1988). The kinase responsible for phosphorylation of this factor has not yet been identified. Simultaneously, RNA polymerase I1 has been found to be redistributed on Drosophila chromosomes, being removed from most non-heat-shock loci and concentrated on heat-shock loci (Jamrich et al. 1977).

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Heat Shock (45°C) Results in an Increase of Nuclear Matrix Protein Mass in HeLa Cells

Cited by 60 publications

References 27 publications

Hyperthermia, thermotolerance and topoisomerase II inhibitors

Hyperthermia, thermotolerance and topoisomerase II inhibitors

Modulation of Cellular Thermoresistance and Actin Filament Stability Accompanies Phosphorylation-Induced Changes in the Oligomeric Structure of Heat Shock Protein 27

Heat‐shock and related stress enhance RNA polymerase II C‐terminal‐domain kinase activity in HeLa cell extracts

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