Cytosolic Heat Shock Protein 60, Hypoxia, and Apoptosis

Gupta, Sanjiv; Knowlton, Anne A

doi:10.1161/01.cir.0000038112.64503.6e

Cited by 145 publications

(104 citation statements)

References 31 publications

(29 reference statements)

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“…A similar observation was made for oxidatively stressed myocytes (hypoxia/ reoxygenation), where translocation of cytosolic Hsp60 to the cell surface induced apoptosis (24). In the cytosol, Hsp60 complexes the propaptotic protein bax, and upon translocation of Hsp60 to the cell surface, the Hsp60/bax complex dissociates and bax relocates into the mitochondria (24). The molecular reason for Hsp60 translocation is not known.…”

mentioning

confidence: 61%

Potential Role of Methionine Sulfoxide in the Inactivation of the Chaperone GroEL by Hypochlorous Acid (HOCl) and Peroxynitrite (ONOO–)

Khor

Fisher

Schöneich

2004

Journal of Biological Chemistry

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GroEL is an Escherichia coli molecular chaperone that functions in vivo to fold newly synthesized polypeptides as well as to bind and refold denatured proteins during stress. This protein is a suitable model for its eukaryotic homolog, heat shock protein 60 (Hsp60), due to the high number of conserved amino acid sequences and similar function. Here, we will provide evidence that GroEL is rather insensitive to oxidants produced endogenously during metabolism, such as nitric oxide ( ⅐ NO) or hydrogen peroxide (H 2 O 2 ), but is efficiently modified and inactivated by reactive species generated by phagocytes, such as peroxynitrite (ONOO ؊ ) and hypochlorous acid (HOCl). For the exposure of 17.5 M GroEL to 100 -250 M HOCl, the major pathway of inactivation was through the oxidation of methionine to methionine sulfoxide, established through mass spectrometric detection of methionine sulfoxide and the reactivation of a significant fraction of inactivated GroEL by the enzyme methionine sulfoxide reductase B/A (MsrB/A). In addition to the oxidation of methionine, HOCl caused the conversion of cysteine to cysteic acid and this product may account for the remainder of inactivated GroEL not recoverable through MsrB/A. In contrast, HOCl produced only negligible yields of 3-chlorotyrosine. A remarkable finding was the conversion of Met 111 and Met 114 to Met sulfone, which suggests a rather low reduction potential of these 2 residues in GroEL. The high sensitivity of GroEL toward HOCl and ONOO ؊ suggests that this protein may be a target for bacterial killing by phagocytes.GroEL and its eukaryotic analog, heat shock protein 60 (Hsp60), 1 are highly sequence-related members of the Group I subclass of chaperonin 60 (Cpn60) (1). These proteins assist the folding of newly synthesized polypeptides (GroEL) or translocated preproteins (mitochondrial Hsp60). The functional unit of GroEL (and of most Cpn60 proteins) is a sandwich of two heptameric rings, which are stacked end to end. Depending on the protein substrate, different ligands such as K ϩ , Mg 2ϩ , ATP, and the cofactor GroES (or Hsp10) may be required for proper folding. Following the trapping of an unfolded or misfolded protein substrate in the hydrophobic interior of GroEL, the binding of ATP and GroES causes a conformational transition, which changes the interior surface properties from hydrophobic to hydrophilic, thus triggering protein folding (1, 2). Mammalian Hsp60 differs from GroEL in that it forms stable and functional heptameric rings in the absence of ATP and its cofactor Hsp10 (3). Our rationale for investigating the oxidative inactivation of GroEL is 2-fold: (i) its potential involvement in bacterial killing by phagocytes and (ii) a potential role for its analog, Hsp60, in an inflammatory and proapoptotic response during cardiovascular disease, as described below.Hsp60 proteins play an important role in the cellular protection against oxidative stress (4, 5). Studies with mutant strains of Saccharomyces cerevisiae exposed to various oxidants show that a decre...

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mentioning

confidence: 61%

Potential Role of Methionine Sulfoxide in the Inactivation of the Chaperone GroEL by Hypochlorous Acid (HOCl) and Peroxynitrite (ONOO–)

Khor

Fisher

Schöneich

2004

Journal of Biological Chemistry

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“…Cells were subjected to 24-hour hypoxia in an anaerobic workstation as described. 12 Cellular injury was estimated by measuring lactate dehydrogenase (LDH) release as described. 13 …”

Section: Hypoxia and Cellular Injurymentioning

confidence: 99%

Estrogen, Heat Shock Proteins, and NFκB in Human Vascular Endothelium

Hamilton

Mbai

Gupta

et al. 2004

ATVB

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Background-We hypothesized that estrogen would increase HSP72 in human coronary artery endothelial cells (HCAEC), and that these would be more sensitive to estrogen than our previous observations in myocytes. Methods and Results-HCAEC were treated with 17␤-estradiol or tamoxifen, ranging from physiological to pharmacological(1 nM to 10 mol/L) for either 24 hours (early) or 7 days (chronic). HSP expression was assessed by Western blots. Both early and chronic 17␤-estradiol and tamoxifen increased HSP72. Electromobility shift assays (EMSA) showed activation of HSF-1 with early, but not chronic, 17␤-estradiol. 17␤-Estradiol activated NF B within 10 minutes, and the ER-␣ selective inhibitor, ICI 182 780, abolished this effect. Transcription factor decoys containing the heat shock element blocked HSP72 induction. Estrogen pretreatment decreased lactate dehydrogenase release with hypoxia. This protective effect persisted despite blockade of HSF-1 by decoys. However, an NF-B decoy prevented the increase in HSP72 and abolished the estrogen-associated protection during hypoxia. Conclusions-17␤-Estradiol upregulates HSP72 early and chronically via different mechanisms in HCAEC, and provides cytoprotection during hypoxia, independent of HSP72 induction. NF-B mediates the early increase in HSP72, suggesting that estrogen activates NF-B via a nongenomic, receptor-dependent mechanism, and this leads to activation of HSF-1. Activation of NF-B was critical for estrogen-associated protection. Further studies are needed to elucidate the involved signaling pathways.

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“…BAX translocation from cytosol to mitochondria is regulated by Hsp60, which binds to BAX in cytosol and inhibits translocation of BAX to mitochondria. BAX dissociates from Hsp60, and translocates to the mitochondria of adult cardiomyocytes under hypoxic conditions (Gupta and Knowlton, 2002).…”

Section: Molecular Chaperones As Regulators Of Cell Death a Hishiya Amentioning

confidence: 99%

Molecular chaperones as regulators of cell death

Hishiya

Takayama

2008

Oncogene

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Cytosolic Heat Shock Protein 60, Hypoxia, and Apoptosis

Abstract: These studies show that hypoxia results in disassociation of the HSP60-bax complex with translocation of cytosolic HSP60 to the plasma membrane and bax to the mitochondria. This is sufficient to trigger apoptosis.

Cited by 145 publications

References 31 publications

Potential Role of Methionine Sulfoxide in the Inactivation of the Chaperone GroEL by Hypochlorous Acid (HOCl) and Peroxynitrite (ONOO–)

Potential Role of Methionine Sulfoxide in the Inactivation of the Chaperone GroEL by Hypochlorous Acid (HOCl) and Peroxynitrite (ONOO–)

Estrogen, Heat Shock Proteins, and NFκB in Human Vascular Endothelium

Molecular chaperones as regulators of cell death

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