Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.7.1.2 (nitrate reductase)
 3,861 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Plant mitochondria possess alternative respiratory pathways mediated by the type II NAD(P)H dehydrogenases and alternative oxidases. Here, E3 SUMO ligase was shown to regulate alternative respiratory pathways and to participate in the maintenance of carbon and nitrogen balance in Arabidopsis. The transcript abundance of the type II NAD(P)H dehydrogenases NDA2 and NDB2 and alternative oxidases AOX1a and AOX1d genes was low in siz1-2 mutants compared to that in wild-type. The addition of nitrate or ammonium resulted in a decrease or an increase in the expression of the same gene families, respectively, in both wild-type and siz1-2 mutants. The amount of free sugar (glucose, fructose and sucrose) was lower in siz1-2 mutants than that in wild-type. These results indicate that low nitrate reductase activity due to the AtSIZ1 mutation is correlated with an overall decrease in alternative respiration and with a low carbohydrate content to maintain the carbon to nitrogen ratio in siz1-2 mutants.
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PMID:Arabidopsis SIZ1 positively regulates alternative respiratory bypass pathways. 2273 19

The activities of mammalian DNA and histone methyltransferases are regulated by post-translational modifications such as phosphorylation and sumoylation; however, it is unclear how the activities of these enzymes are regulated at the post-translational level in plants. Here, we demonstrate that the DNA methylation activity of Arabidopsis CHROMOMETHYLASE 3 (CMT3) is positively regulated by the E3 SUMO ligase AtSIZ1. The methylation level of the Arabidopsis genome, including transposons, was significantly lower in the siz1-2 mutant than in wild-type plants. CMT3 was sumoylated by the E3 ligase activity of AtSIZ1 through a direct interaction, and the DNA methyltransferase activity of CMT3 was enhanced by this modification. In addition, the methylation levels of a large number of genes, including the nitrate reductase gene NIA2, were lower in siz1-2 and cmt3 plants than in wild-type plants. Furthermore, the CHG methylation activity of CMT3 was specific for NIA2and not NIA1 (the other nitrate reductase gene in Arabidopsis), indicating that CMT3 selectively regulates the CHG methylation levels of target genes. Taken together, our results indicate that the sumoylation of CMT3 is critical for its role in the control of gene expression and that AtSIZ1 positively controls the epigenetic repression of CMT3-mediated gene expression.
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PMID:Arabidopsis CMT3 activity is positively regulated by AtSIZ1-mediated sumoylation. 2639 5

Post-translational modifications are essential mediators between stimuli from development or the environment and adaptive transcriptional patterns. Recent data allow a first glimpse at how two modifications, phosphorylation and sumoylation, act interdependently to modulate stress responses. In particular, many components of the SUMO conjugation system are phosphoproteins, and some regulators and enzymes of protein phosphorylation can be sumoylated. Equally important, however, a number of proteins can be subject to both modifications. These substrates also have the capacity to connect stimuli transmitted via sumoylation with those transmitted via phosphorylation. As a prime example, we review data suggesting that nitrate reductase is a hub that integrates cues from these two modifications. Powerful proteomics approaches allowed the identification of additional common substrates, paving the way for studies to understand, on a broader basis, the cross-talk of phosphorylation with sumoylation and how it contributes to plant growth.
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PMID:Sumoylation and phosphorylation: hidden and overt links. 2984 89