Differential Impairment of 20S and 26S Proteasome Activities in Human Hematopoietic K562 Cells during Oxidative Stress

Reinheckel, Thomas; Ullrich, Oliver; Sitte, Nicolle; Grune, Tilman

doi:10.1006/abbi.2000.1717

Cited by 184 publications

(127 citation statements)

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“…For example, exposure of bone marrow neutrophils, cells of acute myelogenous leukemia origin, or endothelial cells to H 2 O 2 or to the H 2 O 2 generating combination of glucose/glucose oxidase resulted in inhibition of 26 S proteasomal function (27,45,46). Of note, these previous experiments also found a differential effect of H 2 O 2 on the 20 S and 26 S proteasomes, with 26 S proteasomal activity being much more sensitive to inhibition by H 2 O 2 than was that of the 20 S proteasome (28,29,53,54). Similarly, increased intracellular concentrations of H 2 O 2 are found in cells from acatalasemic mice or when catalase activity is blocked through treatment with aminotriazole, and both conditions result in greater inhibition of 26 S proteasomal activity as compared with that of the 20 S CP (30).…”

Section: Discussionmentioning

confidence: 78%

“…Increased production of ROS accompanies inflammatory conditions, such as ischemiareperfusion injury and sepsis, and appears to contribute to organ system dysfunction in these settings (25,26). H 2 O 2 rapidly transits across cell membranes, and incubation of neutrophils and other cell populations with H 2 O 2 or the H 2 O 2 generating combination of glucose and glucose oxidase results in increased intracellular concentrations of H 2 O 2 , diminished 26 S proteasomal activity, and stabilization of cytoplasmic levels of proteins, such as IB-␣, that are normally degraded by the 26 S proteasome (27)(28)(29). H 2 O 2 appears to exert a differential effect on 20 S and 26 S proteasomal activities both in vitro and in vivo in H 2 O 2 -exposed neutrophils and other cell populations, with 26 S proteasomal function being much more sensitive to H 2 O 2 than is that of the 20 S CP (27)(28)(29).…”

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confidence: 99%

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S-Glutathionylation of the Rpn2 Regulatory Subunit Inhibits 26 S Proteasomal Function

Żmijewski

Banerjee²,

Abraham

2009

Journal of Biological Chemistry

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Although increased intracellular concentrations of hydrogen peroxide (H 2 O 2 ) are associated with inhibition of 26 S proteasomal activity, the mechanisms responsible for such effects have not been well delineated. In the present studies, we found that direct exposure of purified 26 S proteasomes to H 2 O 2 had negligible effects on their activity, whereas incubation with glutathione and H 2 O 2 produced >80% decrease in chymotrypsin-like and trypsin-like activities. Rpn1 and Rpn2, which are subunits of the 19 S regulatory particle, undergo S-glutathionylation after exposure of purified 26 S proteasomes to glutathione and H 2 O 2 , as well as in HEK 293 cells and neutrophils incubated with H 2 O 2 . Increased oxidation of Rpn1 and Rpn2 cysteine thiols was also found in lung extracts from mice in which catalase was inactivated, a condition associated with augmented intracellular concentrations of H 2 O 2 and diminished 26 S proteasomal activity. Although unoxidized Rpn2 enhanced 20 S proteolytic function in vitro, such potentiation was not found when the 20 S core particle was incubated with oxidized Rpn2. The composition of 26 S proteasomes was not altered after exposure to glutathione and H 2 O 2 , with similar amounts of Rpn1 and Rpn2 in control or oxidized 26 S proteasomal complexes. These findings identify S-glutathionylation of Rpn2 as a contributory mechanism for H 2 O 2 -induced inhibition of 26 S proteasomal function.The ubiquitin-proteasomal system is a major pathway for protein degradation and is involved in multiple cellular processes, including cell cycle control, expression of cell surface receptors, and regulation of intracellular levels of structural and regulatory proteins and transcription factors (1-6). The 26 S proteasome is composed of two main components, a proteolytic 20 S core particle (CP) 2 and an ATPase containing 19 S regulatory particle (RP) (7-10). Ubiquitinated proteins are unfolded in the 19 S RP and then translocated into the 20 S CP where they are degraded. The 20 S CP is composed of four heptameric rings of ␣ and ␤ subunits, with the two inner ␤ rings having proteolytic activity. The 19 S RP consists of a lid and base subcomplex, with the base subcomplex, including the nonenzymatic Rpn1 and Rpn2 toroids, surrounded by six AAA-type ATPases. Rpn1 and Rpn2 appear to play a major regulatory role by modulating the translocation and subsequent degradation of ubiquitinated substrates in the proteolytic core of the 20 S CP (7,(11)(12)(13)(14)(15).Decreased 26 S proteasomal activity, resulting in the accumulation of intracellular proteins, has been associated with aging (16, 17) and with pathophysiologic processes, including heart failure, neurodegenerative diseases, and alcohol induced liver injury (18 -20). A number of recent studies have shown that time-limited inhibition of the 26 S proteasome is beneficial as a therapeutic intervention for malignancies, such as multiple myeloma, and in reducing inflammation and cell injury associated with ischemia-reperfusion injury and transplanta...

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Section: Discussionmentioning

confidence: 78%

mentioning

confidence: 99%

S-Glutathionylation of the Rpn2 Regulatory Subunit Inhibits 26 S Proteasomal Function

Żmijewski

Banerjee²,

Abraham

2009

Journal of Biological Chemistry

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“…3B, proteasome activity was inhibited significantly by 1 mM NDPO 2 in the cells (n ϭ 3; p Ͻ 0.05). This was surprising because earlier studies by our group had demonstrated the resistance of the proteasome toward oxidative stress (13,26,27). Therefore, we tested whether the isolated proteasome is also susceptible toward 1 O 2 .…”

Section: Uva Treatment Increases Protein Carbonyl Formation and Inhibitsmentioning

confidence: 94%

The Proteasome Is an Integral Part of Solar Ultraviolet A Radiation-induced Gene Expression

Karademir

Ziaja

Breusing

et al. 2009

Journal of Biological Chemistry

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Solar ultraviolet (UV)A radiation is a well known trigger of signaling responses in human skin fibroblasts. One important consequence of this stress response is the increased expression of matrix metalloproteinase-1 (MMP-1), which causes extracellular protein degradation and thereby contributes to photoaging of human skin. In the present study we identify the proteasome as an integral part of the UVA-induced, intracellular signaling cascade in human dermal fibroblasts. UVA-induced singlet oxygen formation was accompanied by protein oxidation, the cross-linking of oxidized proteins, and an inhibition of the proteasomal system. This proteasomal inhibition subsequently led to an accumulation of c-Jun and phosphorylated c-Jun and activation of activator protein-1, i.e. transcription factors known to control MMP-1 expression. Increased transcription factor activation was also observed if the proteasome was inhibited by cross-linked proteins or lactacystin, indicating a general mechanism. Most importantly, inhibition of the proteasome was of functional relevance for UVA-induced MMP-1 expression, because overexpression of the proteasome or the protein repair enzyme methionine sulfoxide reductase prevented the UVA-induced induction of MMP-1. These studies show that an environmentally relevant stimulus can trigger a signaling pathway, which links intracellular and extracellular protein degradation. They also identify the proteasome as an integral part of the UVA stress response.Solar ultraviolet A (UVA; 320 -400 nm) radiation is a well known trigger of signaling responses in human dermal fibroblasts in vitro as well as in vivo in human skin (1-3). One important consequence of this stress response is the increased expression of matrix metalloproteinase-1 (MMP-1), 8 which causes extracellular protein degradation and thereby contributes to photoaging of human skin. In fact, UVA-induced MMP-1 expression and the resulting increased degradation of collagen fibers, which occurs primarily in the upper part of the dermis, is thought to be a major reason for wrinkle formation in photoaged human skin (4 -6).The specific signaling steps involved in UVA radiation-induced MMP-1 expression have been extensively examined in recent years. These studies have identified UVA radiation-induced singlet oxygen formation as the initiating event (for review, see Ref. 7) that triggers a cascade of downstream steps which critically involve the activation of the transcription factor complex AP-1 and the subsequent increase in expression of MMP-1. This signaling model, however, includes a black box, because the precise signaling steps linking singlet oxygen with AP-1 activation are largely unknown.In this regard it is of interest that skin fibroblasts in the upper part of the dermis, i.e. exactly the compartment where collagen degradation takes place, contain increased amounts of oxidized proteins (8). The functional relevance of protein oxidation in human skin is not known. Under normal conditions oxidized proteins are being degraded by the proteas...

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“…2) (52,95,128). On the other hand, the 20S proteasome seems to be more resistant to oxidative stress than the 26S proteasome (137,138). It is very likely that during oxidative stress, the 26S proteasome dissociates into the 20S core and the 19S regulators.…”

Section: Repair and Degradation Of Oxidized Proteinsmentioning

confidence: 99%

Protein Oxidation in Aging: Does It Play a Role in Aging Progression?

Reeg

Grune

2015

Antioxidants & Redox Signaling

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158

128

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Significance: A constant accumulation of oxidized proteins takes place during aging. Oxidation of proteins leads to a partial unfolding and, therefore, to aggregation. Protein aggregates impair the activity of cellular proteolytic systems (proteasomes, lysosomes), resulting in further accumulation of oxidized proteins. In addition, the accumulation of highly crosslinked protein aggregates leads to further oxidant formation, damage to macromolecules, and, finally, to apoptotic cell death. Furthermore, protein oxidation seems to play a role in the development of various age-related diseases, for example, neurodegenerative diseases. Recent Advances: The highly oxidized lipofuscin accumulates during aging. Lipofuscin formation might cause impaired lysosomal and proteasomal degradation, metal ion accumulation, increased reactive oxygen species formation, and apoptosis. Critical Issues: It is still unclear to which extent protein oxidation is involved in the progression of aging and in the development of some age-related diseases. Future Directions: An extensive knowledge of the effects of protein oxidation on the aging process and its contribution to the development of age-related diseases could enable further strategies to reduce age-related impairments. Strategies aimed at lowering aggregate formation might be a straightforward intervention to reduce age-related malfunctions of organs. Antioxid. Redox Signal. 23, 239-255.

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Differential Impairment of 20S and 26S Proteasome Activities in Human Hematopoietic K562 Cells during Oxidative Stress

Cited by 184 publications

References 17 publications

S-Glutathionylation of the Rpn2 Regulatory Subunit Inhibits 26 S Proteasomal Function

S-Glutathionylation of the Rpn2 Regulatory Subunit Inhibits 26 S Proteasomal Function

The Proteasome Is an Integral Part of Solar Ultraviolet A Radiation-induced Gene Expression

Protein Oxidation in Aging: Does It Play a Role in Aging Progression?

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