Heat‐induced nuclear accumulation of hsc70 proteins is regulated by phosphorylation and inhibited in confluent cells

Chu, Angel; Matusiewicz, Neola; Stochaj, Ursula

doi:10.1096/fj.00-0680fje

Cited by 39 publications

(41 citation statements)

References 33 publications

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“…To this end, HeLa cells were pretreated with either drug under conditions known to block the activation of ERK1/2. 10 As shown in Figure 1C and published previously, 10 the inhibitor concentrations used in our experiments prevented stress-induced phosphorylation and thereby activation of ERK1/2 in HeLa cells. However, neither PD98059 nor genistein were able to abolish the inhibitory effect of hydrogen peroxide on classical nuclear protein import ( Figure 1B, d, f).…”

Section: Nuclear Import Inhibition By Hydrogen Peroxide Cannot Be Abosupporting

confidence: 78%

“…10 The small size of NLS-GFP allows diffusion across the NPC, a process independent of active transport. In addition, the simple SV40-NLS is recognized by the classical transport apparatus, which imports NLS-GFP into the nucleus.…”

Section: Resultsmentioning

confidence: 99%

“…40 At approximately 70% confluency, cells were subjected to 10 mM hydrogen peroxide (or the oxidant concentration given in the figure legends) in growth medium and incubated for 1 h at 371C. Incubation with the kinase inhibitors PD98059 and genistein was carried out as in Chu et al 10 To test the role of the proteasome, cells were preincubated for 30 min with 10 mM MG132 or for 2 h with 50 mM lactacystin (Calbiochem, San Diego, CA, USA) in growth medium. Cells were pretreated with 15 mM caspase inhibitor (Ac-DEVD-CHO, Calbiochem) or 50 mM calpain inhibitor I (MG101, Sigma, Oakville, ON, USA) 2 h before stress exposure.…”

Section: Methodsmentioning

confidence: 99%

“…7 Nucleocytoplasmic trafficking of macromolecules is sensitive to stress; heat shock, ethanol and oxidative stress inhibit classical nuclear protein import. 8,9,10 In growing yeast cells and in semi-permeabilized smooth muscle cells in vitro, oxidants have been shown to interfere with classical nuclear import. In these model systems, redistribution of the small GTPase Gsp1p/Ran from the nucleus to the cytoplasm is believed to contribute to nuclear import inhibition.…”

Section: Introductionmentioning

confidence: 99%

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Multiple mechanisms promote the inhibition of classical nuclear import upon exposure to severe oxidative stress

et al. 2004

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In growing HeLa cells, severe stress elicited by the oxidant hydrogen peroxide inhibits classical nuclear import. Oxidant treatment collapses the nucleocytoplasmic Ran concentration gradient, thereby elevating cytoplasmic GTPase levels. The Ran gradient dissipates in response to a stress-induced depletion of RanGTP and a decreased efficiency of Ran nuclear import. In addition, oxidative stress induces a relocation of the nucleoporin Nup153 as well as the nuclear carrier importin-b, and docking of the importin-a/b/cargo complex at the nuclear envelope is reduced. Moreover, Ran, importin-b and Nup153 undergo proteolysis upon oxidative stress. Caspases and the proteasome degrade Ran and importin-b; however, ubiquitination of these transport factors is not observed. Inhibition of caspases in stressed cells alleviates the mislocalization of importin-b, but does not restore the Ran concentration gradient or classical import. In summary, inhibition of classical nuclear import by hydrogen peroxide is caused by a combination of multiple mechanisms that target different components of the transport apparatus.

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Section: Nuclear Import Inhibition By Hydrogen Peroxide Cannot Be Abosupporting

confidence: 78%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Multiple mechanisms promote the inhibition of classical nuclear import upon exposure to severe oxidative stress

et al. 2004

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“…There is increasing evidence that phosphorylation of cell-surface-expressed heat shock proteins (HSPs) are intimately involved in tumor cell adhesion, motility, and invasion (32,33). The effect of specific tyrosine phosphorylation of HSPA8 in mitotic and tumor cells (34) on cellular localization and function (35) has been demonstrated. In human D54MG glioma cells, siRNA-mediated knockdown of HSPA8 expression is associated with decreased glioma cell migration through vitronectin-coated membranes (36).…”

Section: Discussionmentioning

confidence: 99%

Overexpression of ST6GalNAcV, a ganglioside-specific α2,6-sialyltransferase, inhibits glioma growth in vivo

Kroes

Emmett

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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Aberrant cell-surface glycosylation patterns are present on virtually all tumors and have been linked to tumor progression, metastasis, and invasivity. We have shown that expressing a normally quiescent, glycoprotein-specific α2,6-sialyltransferase (ST6Gal1) gene in gliomas inhibited invasivity in vitro and tumor formation in vivo. To identify other glycogene targets with therapeutic potential, we created a focused 45-mer oligonucleotide microarray platform representing all of the cloned human glycotranscriptome and examined the glycogene expression profiles of 10 normal human brain specimens, 10 malignant gliomas, and 7 human glioma cell lines. Among the many significant changes in glycogene expression observed, of particular interest was the observation that an additional α2,6-sialyltransferase, ST6 (α-N-acetyl-neuraminyl-2,3-β-galactosyl-1,3)-N-acetylgalactosaminide α2,6-sialyltransferase 5 (ST6GalNAcV), was expressed at very low levels in all glioma and glioma cell lines examined compared with normal brain. ST6GalNAcV catalyzes the formation of the terminal α2,6-sialic acid linkages on gangliosides. Stable transfection of ST6GalNAcV into U373MG glioma cells produced (i) no change in α2,6-linked sialic acid-containing glycoproteins, (ii) increased expression of GM2α and GM3 gangliosides and decreased expression of GM1b, Gb3, and Gb4, (iii) marked inhibition of in vitro invasivity, (iv) modified cellular adhesion to fibronectin and laminin, (v) increased adhesion-mediated protein tyrosine phosphorylation of HSPA8, and (vi) inhibition of tumor growth in vivo. These results strongly suggest that modulation of the synthesis of specific glioma cell-surface glycosphingolipids alters invasivity in a manner that may have significant therapeutic potential.glycosyltransferase | glycosphingolipid | glioblastoma | heat shock 70 kDa protein 8 | glycosynapse

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Differential expression of multiple anti‐apoptotic proteins in epidermis of IGF‐1 transgenic mice as revealed by 2‐dimensional gel electrophoresis/mass spectrometry analysis

Shen

Riggs

Hensley

et al. 2007

Molecular Carcinogenesis

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Overexpression of insulin-like growth factor-1 (IGF-1) has been associated with a number of human tumors, including breast, colon, lung, and prostate cancers. In previous studies, we found that mice overexpressing human IGF-1 in the basal layer of the epidermis (BK5.IGF-1 mice) developed skin tumors following treatment with the skin tumor initiator, 7,12-dimethylbenz[a]anthracene, indicating that IGF-1 can act as a skin tumor promoter. In the present study, we employed a proteomics approach of two-dimensional (2-D) gel electrophoresis and mass spectrometry to profile differentially expressed proteins in skin epidermis between BK5.IGF-1 transgenic and nontransgenic littermates. Two-D gels from each of three transgenic and three age/sex matched wild-type littermates were compared at two different pH ranges. Differentially expressed protein spots were identified by Bio-Rad's PDQuest image analysis, in-gel digested, and analyzed on a MALDI-TOF MS system. A total of 23 proteins were identified as differentially expressed, 17 of them overexpressed in transgenic mice. These proteins included 14-3-3 sigma, galectin-7, an apoptosis-related protein, three heat shock proteins, four calcium binding proteins, three proteases or protease inhibitors, one actin regulatory capping protein, and translation initiation factor 5A. The differential expression of GRP78, alpha enolase, and galectin-7 was verified by 1-D western blot analysis. Two-D western blot analyses of alpha enolase and galectin-7 further revealed that alpha enolase had more than one protein spot dependent on charge. The current data suggest that some of the differentially expressed proteins may play a role in the tumor promoting action of IGF-1 in mouse skin.

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Heat‐induced nuclear accumulation of hsc70 proteins is regulated by phosphorylation and inhibited in confluent cells

Cited by 39 publications

References 33 publications

Multiple mechanisms promote the inhibition of classical nuclear import upon exposure to severe oxidative stress

Multiple mechanisms promote the inhibition of classical nuclear import upon exposure to severe oxidative stress

Overexpression of ST6GalNAcV, a ganglioside-specific α2,6-sialyltransferase, inhibits glioma growth in vivo

Differential expression of multiple anti‐apoptotic proteins in epidermis of IGF‐1 transgenic mice as revealed by 2‐dimensional gel electrophoresis/mass spectrometry analysis

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