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Differential molecular response of monodehydroascorbate reductase and glutathione reductase by nitration and S-nitrosylation.

Begara-Morales JC, Sánchez-Calvo B, Chaki M, Mata-Pérez C, Valderrama R, Padilla MN, López-Jaramillo J, Luque F, Corpas FJ, Barroso JB - J. Exp. Bot. (2015)

Bottom Line: The location of these residues in the structure of pea peroxisomal MDAR reveals that Tyr345 is found at 3.3 Å of His313 which is involved in the NADP-binding site.However, GR was not affected by ONOO(-) or GSNO, suggesting the existence of a mechanism to conserve redox status by maintaining the level of reduced GSH.Under a nitro-oxidative stress induced by salinity (150mM NaCl), MDAR expression (mRNA, protein, and enzyme activity levels) was increased, probably to compensate the inhibitory effects of S-nitrosylation and nitration on the enzyme.

View Article: PubMed Central - PubMed

Affiliation: Group of Biochemistry and Cell Signaling in Nitric Oxide, Biochemistry and Molecular Biology Division, Department of Experimental Biology, Faculty of Experimental Sciences, University of Jaén, Campus 'Las Lagunillas', E-23071 Jaén, Spain.

No MeSH data available.


Related in: MedlinePlus

Regulation of the ascorbate–glutathione cycle by nitric oxide (NO). NO modulates the ascorbate–glutathione cycle throughout post-translational modifications (PTMs) as tyrosine nitration and S-nitrosylation of APX and MDAR proteins. MDAR activity is reduced after both modifications, with APX activity also being reduced by tyrosine nitration. Under nitro-oxidative stress conditions, these modifications could compromise the antioxidant capacity of the cycle. However, APX activity is enhanced by S-nitrosylation while GR activity is not significantly affected by these NO-related PTMs. This behaviour suggests that APX and GR try to detoxify hydrogen peroxide and maintain regeneration of GSH, respectively, and consequently the cellular redox state to maintain the antioxidant resistance of the ascorbate–glutathione cycle against nitro-oxidative cell conditions. (This figure is available in colour at JXB online.)
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Figure 6: Regulation of the ascorbate–glutathione cycle by nitric oxide (NO). NO modulates the ascorbate–glutathione cycle throughout post-translational modifications (PTMs) as tyrosine nitration and S-nitrosylation of APX and MDAR proteins. MDAR activity is reduced after both modifications, with APX activity also being reduced by tyrosine nitration. Under nitro-oxidative stress conditions, these modifications could compromise the antioxidant capacity of the cycle. However, APX activity is enhanced by S-nitrosylation while GR activity is not significantly affected by these NO-related PTMs. This behaviour suggests that APX and GR try to detoxify hydrogen peroxide and maintain regeneration of GSH, respectively, and consequently the cellular redox state to maintain the antioxidant resistance of the ascorbate–glutathione cycle against nitro-oxidative cell conditions. (This figure is available in colour at JXB online.)

Mentions: In summary, the present results provide new insights into the molecular mechanism involved in regulating MDAR and GR through PTMs mediated by NO-derived molecules and confirm the close involvement of NO and ROS metabolism in the antioxidant defence against nitro-oxidative stress situations in plants. These data, together with previous findings on the dual regulation of APX by S-nitrosylation/nitration (Begara-Morales et al., 2014), are summarized in Fig. 6. It shows the modulation of the antioxidative response of key enzymes in the ascorbate–glutathione cycle by NO-PTMs, where MDAR was deactivated by nitration and S-nitrosylation, which could compromise the cycle’s antioxidant capacity. However, GR was not affected by any of these NO-PTMs in an attempt to maintain the levels of GSH and the cellular redox state, suggesting that this could be a crucial mechanism to sustain the antioxidant capacity of the ascorbate–glutathione cycle against nitro-oxidative cell conditions.


Differential molecular response of monodehydroascorbate reductase and glutathione reductase by nitration and S-nitrosylation.

Begara-Morales JC, Sánchez-Calvo B, Chaki M, Mata-Pérez C, Valderrama R, Padilla MN, López-Jaramillo J, Luque F, Corpas FJ, Barroso JB - J. Exp. Bot. (2015)

Regulation of the ascorbate–glutathione cycle by nitric oxide (NO). NO modulates the ascorbate–glutathione cycle throughout post-translational modifications (PTMs) as tyrosine nitration and S-nitrosylation of APX and MDAR proteins. MDAR activity is reduced after both modifications, with APX activity also being reduced by tyrosine nitration. Under nitro-oxidative stress conditions, these modifications could compromise the antioxidant capacity of the cycle. However, APX activity is enhanced by S-nitrosylation while GR activity is not significantly affected by these NO-related PTMs. This behaviour suggests that APX and GR try to detoxify hydrogen peroxide and maintain regeneration of GSH, respectively, and consequently the cellular redox state to maintain the antioxidant resistance of the ascorbate–glutathione cycle against nitro-oxidative cell conditions. (This figure is available in colour at JXB online.)
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4566986&req=5

Figure 6: Regulation of the ascorbate–glutathione cycle by nitric oxide (NO). NO modulates the ascorbate–glutathione cycle throughout post-translational modifications (PTMs) as tyrosine nitration and S-nitrosylation of APX and MDAR proteins. MDAR activity is reduced after both modifications, with APX activity also being reduced by tyrosine nitration. Under nitro-oxidative stress conditions, these modifications could compromise the antioxidant capacity of the cycle. However, APX activity is enhanced by S-nitrosylation while GR activity is not significantly affected by these NO-related PTMs. This behaviour suggests that APX and GR try to detoxify hydrogen peroxide and maintain regeneration of GSH, respectively, and consequently the cellular redox state to maintain the antioxidant resistance of the ascorbate–glutathione cycle against nitro-oxidative cell conditions. (This figure is available in colour at JXB online.)
Mentions: In summary, the present results provide new insights into the molecular mechanism involved in regulating MDAR and GR through PTMs mediated by NO-derived molecules and confirm the close involvement of NO and ROS metabolism in the antioxidant defence against nitro-oxidative stress situations in plants. These data, together with previous findings on the dual regulation of APX by S-nitrosylation/nitration (Begara-Morales et al., 2014), are summarized in Fig. 6. It shows the modulation of the antioxidative response of key enzymes in the ascorbate–glutathione cycle by NO-PTMs, where MDAR was deactivated by nitration and S-nitrosylation, which could compromise the cycle’s antioxidant capacity. However, GR was not affected by any of these NO-PTMs in an attempt to maintain the levels of GSH and the cellular redox state, suggesting that this could be a crucial mechanism to sustain the antioxidant capacity of the ascorbate–glutathione cycle against nitro-oxidative cell conditions.

Bottom Line: The location of these residues in the structure of pea peroxisomal MDAR reveals that Tyr345 is found at 3.3 Å of His313 which is involved in the NADP-binding site.However, GR was not affected by ONOO(-) or GSNO, suggesting the existence of a mechanism to conserve redox status by maintaining the level of reduced GSH.Under a nitro-oxidative stress induced by salinity (150mM NaCl), MDAR expression (mRNA, protein, and enzyme activity levels) was increased, probably to compensate the inhibitory effects of S-nitrosylation and nitration on the enzyme.

View Article: PubMed Central - PubMed

Affiliation: Group of Biochemistry and Cell Signaling in Nitric Oxide, Biochemistry and Molecular Biology Division, Department of Experimental Biology, Faculty of Experimental Sciences, University of Jaén, Campus 'Las Lagunillas', E-23071 Jaén, Spain.

No MeSH data available.


Related in: MedlinePlus