Selective Induction of Chinese Hamster Hsp27 Into Mouse Cells Confers Thermoresistance

Lavoie, Jessie R.; Landry, Jacques

doi:10.1016/b978-0-12-168561-4.50373-5

Cited by 43 publications

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“…Suggested functions have included involvement in signal transduction, resistance to thermal and metabolic stress, growth and differentiation, and serving as a molecular chaperone (41)(42)(43)(44)(45)(46)(47). Recent reports identified hsp27 as an actin-associated protein (21) which inhibits actin polymerization in vitro (22).…”

Section: Discussionmentioning

confidence: 99%

Altered expression of glomerular heat shock protein 27 in experimental nephrotic syndrome.

Smoyer¹,

Gupta²,

Mündel

et al. 1996

J. Clin. Invest.

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Although nephrotic syndrome is a very common kidney disease, little is known about the molecular changes occurring within glomerular capillary loops during development of disease. The characteristic histologic change is retraction (effacement) of the distal "foot" processes of glomerular epithelial cells (GEC) which surround the capillary loops. The GEC foot processes are an essential part of the kidney's filtration barrier, and their structure is regulated primarily by actin microfilaments, cytoskeletal proteins present in high concentrations in foot processes. Actin polymerization has been reported to be regulated via phosphorylation of the low molecular weight heat shock protein, hsp27. We localized hsp27 within normal rat GECs using immunofluorescence and immunoelectron microscopy. Induction of nephrotic syndrome and GEC foot process effacement using the puromycin aminonucleoside rat model resulted in significant increases in: ( a ) renal cortical hsp27 mRNA expression

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Section: Discussionmentioning

confidence: 99%

Altered expression of glomerular heat shock protein 27 in experimental nephrotic syndrome.

Smoyer¹,

Gupta²,

Mündel

et al. 1996

J. Clin. Invest.

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“…In cardiac muscle sHSPs colocalize with actin (34). In culture cells, increased stress resistance conferred by ectopic sHSP expression correlates with increased stability of stress fibers (31). Avian and yeast sHSPs have been shown to inhibit actin polymerization in vitro (39,40,43), and studies with a murine sHSP showed that this ability to interfere with actin polymerization is regulated by phosphorylation and multimerization (7).…”

Section: Cdc2mentioning

confidence: 99%

Small Heat Shock Protein Suppression of Vpr-Induced Cytoskeletal Defects in Budding Yeast

Emerman

Sandmeyer

1997

Molecular and Cellular Biology

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Expression of the auxiliary human immunodeficiency virus type 1 (HIV-1) protein Vpr causes arrest of primate host cells in G 2 . Expression of this protein in budding yeast has been previously reported to cause growth arrest and a large-cell phenotype. Investigation of the effect of Vpr expression in budding yeast, reported here, showed that it causes disruption of the actin cytoskeleton. Expression of HSP42, the gene for a small heat shock protein (sHSP), from a high-copy-number plasmid reversed this effect. The sHSPs are induced by exposure of cells to thermal, osmotic, and oxidative stresses and to mitogens. In animal cells, overexpression of sHSPs causes increased resistance to stress and stabilization of actin stress fibers. Yeast cells subjected to mild stress, such as shifting from 23 to 39°C, arrest growth and then resume cell division. Growth arrest is accompanied by transient disorganization of the cytoskeleton. Yeast in which the HSP42 gene was disrupted and which was subjected to moderate thermal stress reorganized the actin cytoskeleton more slowly than did wild-type control cells. These results demonstrate that in yeast, as in metazoan cells, sHSPs promote maintenance of the actin cytoskeleton.

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“…In vivo, expression of Hsp27 increases cellular resistance against heat shock (1) and different other injuries, such as those mediated by chemotherapeutic drugs (2) or oxidative stress (e.g., tumor necrosis factor alpha) (46,62). This protection may be a result of the reduced-glutathione-dependent in vivo chaperone activity of Hsp27 against misfolded or oxidized proteins (59) and/or of the stabilization of actin microfilaments by Hsp27 (19,27,34,36,43). Hsp27 has also been indirectly implicated in membrane blebbing formation by stressing agents through its SAP kinase 2-triggered actin polymerization-generating activity (26).…”

mentioning

confidence: 99%

Hsp27 as a Negative Regulator of Cytochrome c Release

Paul

Manero

Gonin

et al. 2002

Molecular and Cellular Biology

403

333

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We previously showed that Hsp27 protects against apoptosis through its interaction with cytosolic cytochrome c. We have revisited this protective activity in murine cell lines expressing different levels of Hsp27. We report that Hsp27 also interferes, in a manner dependent on level of expression, with the release of cytochrome c from mitochondria. Moreover, a decreased level of endogenous Hsp27, which sensitized HeLa cells to apoptosis, reduced the delay required for cytochrome c release and procaspase 3 activation. The molecular mechanism regulating this function of Hsp27 is unknown. In our cell systems, Hsp27 is mainly cytosolic and only a small fraction of this protein colocalized with mitochondria. Moreover, we show that only a very small fraction of cytochrome c interacts with Hsp27, hence excluding a role of this interaction in the retention of cytochrome c in mitochondria. We also report that Bid intracellular relocalization was altered by changes in Hsp27 level of expression, suggesting that Hsp27 interferes with apoptotic signals upstream of mitochondria. We therefore investigated if the ability of Hsp27 to act as an expression-dependent modulator of F-actin microfilaments integrity was linked to the retention of cytochrome c in mitochondria. We show here that the F-actin depolymerizing agent cytochalasin D rapidly induced the release of cytochrome c from mitochondria and caspase activation. This phenomenon was delayed in cells pretreated with the F-actin stabilizer phalloidin and in cells expressing a high level of Hsp27. This suggests the existence of an apoptotic signaling pathway linking cytoskeleton damages to mitochondria. This pathway, which induces Bid intracellular redistribution, is negatively regulated by the ability of Hsp27 to protect F-actin network integrity. However, this upstream pathway is probably not the only one to be regulated by Hsp27 since, in staurosporine-treated cells, phalloidin only partially inhibited cytochrome c release and caspase activation. Moreover, in etoposide-treated cells, Hsp27 still delayed the release of cytochrome c from mitochondria and Bid intracellular redistribution in conditions where F-actin was not altered.

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Selective Induction of Chinese Hamster Hsp27 Into Mouse Cells Confers Thermoresistance

Cited by 43 publications

References 0 publications

Altered expression of glomerular heat shock protein 27 in experimental nephrotic syndrome.

Altered expression of glomerular heat shock protein 27 in experimental nephrotic syndrome.

Small Heat Shock Protein Suppression of Vpr-Induced Cytoskeletal Defects in Budding Yeast

Hsp27 as a Negative Regulator of Cytochrome c Release

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