REDOX REGULATION: A Broadening Horizon

Buchanan, Bob B.; Balmer, Yves

doi:10.1146/annurev.arplant.56.032604.144246

Cited by 784 publications

(684 citation statements)

References 204 publications

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“…Glutaredoxins (GRXs) are small, ubiquitous, glutathione-dependent oxidoreductases that play an essential role in response to oxidative stress (Buchanan and Balmer, 2005). According to the amino acid sequences of active site motifs, three classes of GRXs are defined in plants, namely the CPYC, the CGFS, and the CCtype classes (Rouhier et al, 2004).…”

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confidence: 99%

The ROXY1 C-Terminal L**LL Motif Is Essential for the Interaction with TGA Transcription Factors

Gutsche

Zachgo

2011

Plant Physiology

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Glutaredoxins (GRXs) are small, ubiquitous, glutathione-dependent oxidoreductases that participate in redox-regulated processes associated with stress responses. Recently, GRXs have been shown to exert crucial functions during flower developmental processes. GRXs modulate their target protein activities by the reduction of protein disulfide bonds or deglutathionylation reactions. The Arabidopsis (Arabidopsis thaliana) GRX ROXY1 participates in petal primordia initiation and further petal morphogenesis. ROXY1 belongs to a land plant-specific class of GRXs with a CC-type active site motif, deviating from the ubiquitously occurring CPYC and CGFS GRX classes. ROXY1 was previously shown to interact with floral TGA transcription factors in the nucleus, and this interaction is a prerequisite for ROXY1 to exert its activity required for Arabidopsis petal development. Deletion analysis further identified the importance of the ROXY1 C terminus for the ROXY1/ TGA protein interactions and for the ROXY1 function in petal development. Here, by dissecting the ROXY1 C terminus, an a-helical L**LL motif immediately adjacent to the ROXY1 C-terminal eight amino acids was identified that is essential for the interaction with TGA transcription factors and crucial for the ROXY1 function in planta. Similar to the a-helical L**LL motifs binding to transcriptional coactivators with liganded nuclear receptors in animals, a hydrophobic face formed by the conserved leucines in the L**LL motif of ROXY1 possibly mediates the interaction with TGA transcription factors. Thus, the a-helical L**LL sequence is a conserved protein-protein interaction motif in both animals and plants. Furthermore, two separate TGA domains were identified by deletion experiments as being essential for mediating TGA protein interactions with ROXYs.

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confidence: 99%

The ROXY1 C-Terminal L**LL Motif Is Essential for the Interaction with TGA Transcription Factors

Gutsche

Zachgo

2011

Plant Physiology

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“…However, PEGcatalase, PEG-SOD, and vitamin C were inefficient in inhibiting the radiation-induced increase in CD20 expression. This may be due to their specificity for neutralizing a more limited range of free radicals than what is produced by radiation, which generates superoxide, H 2 O 2 , hydroxyl radical, nitric oxide, and peroxynitrite [15,28,31]. Strikingly, amifostine could completely inhibit the radiation-induced increase in CD20 levels.…”

Section: Discussionmentioning

confidence: 99%

“…The Recent studies have reported that bryostatin-1, interleukin-4, granulocyte-macrophage colony-stimulating factor, tumor necrosis factor-α, and interferon-α are all able to induce CD20 surface expression [8][9][10][11][12][13]. However, the mechanisms regulating the expression of CD20 remain poorly understood, even though these cytokines are well known to cause robust intracellular oxidative bursts [14,15]. Recently, it was shown that the bryostatin-1-induced increase of CD20 was regulated at the transcriptional level.…”

Section: Introductionmentioning

confidence: 99%

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Regulation of CD20 expression by radiation-induced changes in intracellular redox status

Gupta

Crosby

Almasan

et al. 2008

Free Radical Biology and Medicine

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Increasing the levels of CD20 expression in cells that harbor low CD20 levels may enhance their responsiveness to CD20-specific antibody therapies. Here, we examined the regulation of CD20 expression after treatment with 0.5-2.0 Gy X-irradiation and hydrogen peroxide (H 2 O 2 ), in the presence or absence of known antioxidants, in the Burkitt lymphoma cell lines Daudi and Raji. Irradiation of cells enhanced cell-surface CD20 expression; the kinetics and extent of this change were cell-type specific and time-dependent. The kinetics of reactive oxygen species generation and changes in mitochondrial membrane potential after irradiation were also correlated with changes in CD20 expression. Raji and Daudi cells treated with H 2 O 2 showed a 2-to 2.5-fold increase in CD20 expression at 12 and 20 h, respectively. Buthionine sulfoximine, which depletes glutathione, also increased surface CD20, whereas antioxidants, such as PEG-catalase, PEG-SOD, vitamin C, and amifostine, decreased CD20 expression induced by radiation or H 2 O 2 . The antioxidant-mediated decrease in CD20 expression induced by radiation or H 2 O 2 suggests a mechanism involving redox regulation. These results demonstrate the critical role of radiationinduced oxidative stress in CD20 expression and may have implications for defining and improving the efficacy of CD20-targeted antibody therapy and radioimmunotherapy. Keywords CD20; Ionizing radiation; Reactive oxygen species; Antioxidants; Mitochondria; Mitochondrial membrane potential; Free radicals The CD20 transmembrane protein is exclusively expressed on B cells. It appears during the pre-B-cell stage, but is absent during the earlier or later stages of B cell differentiation, such as in antibody-secreting plasma cells [1,2]. CD20 has received extensive evaluation as an ideal target for immunotherapy and radioimmunotherapy, in part because of its ubiquitous expression on target cells, stable localization within the cell membrane, and absence from normal stem cells [3]. Rituximab, a chimeric monoclonal anti-CD20 antibody, has been used extensively in the treatment of low-grade B cell lymphomas, such as non-Hodgkin lymphoma (NHL) and other related pathologies. In clinical applications, the efficacy of Rituximab seems to fade after a period of months, leading to Rituximab resistance. The Recent studies have reported that bryostatin-1, interleukin-4, granulocyte-macrophage colony-stimulating factor, tumor necrosis factor-α, and interferon-α are all able to induce CD20 surface expression [8][9][10][11][12][13]. However, the mechanisms regulating the expression of CD20 remain poorly understood, even though these cytokines are well known to cause robust intracellular oxidative bursts [14,15]. Recently, it was shown that the bryostatin-1-induced increase of CD20 was regulated at the transcriptional level. The effect of bryostatin-1 on CD20 expression in NHL-derived cells was apparently mediated through the MAPK/ERK signal transduction pathway and involved protein kinase C [13]. Our group has previous...

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“…The proteins that promote protein glutathionylation in vivo in plant cells are unknown but the reverse reaction (deglutathionylation) is thought to be catalysed by GRXs, which are reduced by GSH. Many important enzymes of photosynthetic carbon assimilationin the Benson-Calvincycle in chloroplasts and associated pathways are regulated by TRX in a redox-dependent manner (24). Chloroplast TRX and the enzymes of the Benson-Calvin cycle in chloroplasts are major targets of glutathionylation (25)(26)(27).…”

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confidence: 99%

Glutathione – linking cell proliferation to oxidative stress

Díaz‐Vivancos

Simone

Kiddle³

et al. 2015

Free Radical Biology and Medicine

256

158

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Significance:The multifaceted functions of reduced glutathione (gamma-glutamyl-cysteinyl-glycine; GSH) continue to fascinate plants and animal scientists, not least because of the dynamic relationships between GSH and reactive oxygen species (ROS) that underpin reduction/oxidation (redox) regulation and signalling. Here we consider the respective roles of ROS and GSH in the regulation of plant growth, with a particular focus on regulation of the plant cell cycle. Glutathione is discussed not only as a crucial low molecular weight redox buffer that shields nuclear processes against oxidative challenge but also a flexible regulator of genetic and epigenetic functions. Recent Advances:The intracellular compartmentalization of GSH during the cell cycle is remarkably consistent in plants and animals. Moreover, measurements of in vivo glutathione redox potentials reveal that the cellular environment is much more reducing than predicted from GSH/GSSG ratios measured in tissue extracts. The redox potential of the cytosol and nuclei of non-dividing plant cells is about -300 mV. This relatively low redox potential is maintained even in cells experiencing oxidative stress by a number of mechanisms including vacuolar sequestration of GSSG. We propose that regulated ROS production linked to glutathione-mediated signalling events are the hallmark of viable cells within a changing and challenging environment. Critical Issues:The concept that the cell cycle in animals is subject to redox controls is well established but little is known about how ROS and GSH regulate this process in plants. However, it is increasingly likely that similar redox controls exist in plants, 3 although possibly through different pathways. Moreover, redox-regulated proteins that function in cell cycle checkpoints remain to be identified in plants. While GSHresponsive genes have now been identified, the mechanisms that mediate and regulate protein glutathionylation in plants remain poorly defined.Future Directions: The nuclear GSH pool provides an appropriate redox environment for essential nuclear functions. Future work will function on how this essential thiol interacts with the nuclear thioredoxin system and nitric oxide to regulate genetic and epigenetic mechanisms. The characterization of redox-regulated cell cycle proteins in plants, and the elucidation of mechanisms that facilitate GSH accumulation in the nucleus are keep steps to unravelling the complexities of nuclear redox controls.Diaz 4

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REDOX REGULATION: A Broadening Horizon

Cited by 784 publications

References 204 publications

The ROXY1 C-Terminal L**LL Motif Is Essential for the Interaction with TGA Transcription Factors

The ROXY1 C-Terminal L**LL Motif Is Essential for the Interaction with TGA Transcription Factors

Regulation of CD20 expression by radiation-induced changes in intracellular redox status

Glutathione – linking cell proliferation to oxidative stress

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