Phosphorylation and subsequent interaction with 14-3-3 proteins regulate plastid glutamine synthetase in Medicago truncatula

Lima, Lígia; Seabra, Ana R.; Melo, Paula; Cullimore, Julie V.; Carvalho, Helena

doi:10.1007/s00425-005-0097-8

Cited by 57 publications

(41 citation statements)

References 44 publications

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“…Another potential level of complexity in the nod26-GS interaction comes from the observation that both binding partners are subject to post-translational phosphorylation (5,(55)(56)(57). In the case of nod26, the unique site of phosphorylation is Ser 262 (55), which resides in the C-terminal domain, which is the site of GS interaction.…”

Section: Discussionmentioning

confidence: 99%

“…Preliminary analyses suggest that nod26 peptides that are phosphorylated at Ser 262 retain the ability to bind to GS in vitro, but the influence of phosphorylation on the assembly and activity of the complex in vivo remains to be addressed. Cytosolic GS 1 is also a target for posttranslational phosphorylation by various protein kinases in plant tissues (56,57), with phosphorylation potentially leading to interaction with 14-3-3 proteins (56) and other unidentified phosphoproteins (57). The interplay between phosphorylation, GS regulation, and interaction with nod26 and other potential regulatory targets and the effects of these on N 2 fixation and assimilation in response to environmental cues remain a topic for future investigation.…”

Section: Discussionmentioning

confidence: 99%

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Interaction of Cytosolic Glutamine Synthetase of Soybean Root Nodules with the C-terminal Domain of the Symbiosome Membrane Nodulin 26 Aquaglyceroporin

Masalkar

Wallace

Hwang

et al. 2010

Journal of Biological Chemistry

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Nodulin 26 (nod26) is a major intrinsic protein that constitutes the major protein component on the symbiosome membrane (SM) of N 2 -fixing soybean nodules. Functionally, nod26 forms a low energy transport pathway for water, osmolytes, and NH 3 across the SM. Besides their transport functions, emerging evidence suggests that high concentrations of major intrinsic proteins on membranes provide interaction and docking targets for various cytosolic proteins. Here it is shown that the C-terminal domain peptide of nod26 interacts with a 40-kDa protein from soybean nodule extracts, which was identified as soybean cytosolic glutamine synthetase GS 1 ␤1 by mass spectrometry. Fluorescence spectroscopy assays show that recombinant soybean GS 1 ␤1 binds the nod26 C-terminal domain with a 1:1 stoichiometry (K d ‫؍‬ 266 nM). GS 1 ␤1 also binds to isolated SMs, and this binding can be blocked by preincubation with the C-terminal peptide of nod26. In vivo experiments using either a split ubiquitin yeast two-hybrid system or bimolecular fluorescence complementation show that the four cytosolic GS isoforms expressed in soybean nodules interact with full-length nod26. The binding of GS, the principal ammonia assimilatory enzyme, to the conserved C-terminal domain of nod26, a transporter of NH 3 , is proposed to promote efficient assimilation of fixed nitrogen, as well as prevent potential ammonia toxicity, by localizing the enzyme to the cytosolic side of the symbiosome membrane.The formation of legume-rhizobia N 2 -fixing symbioses in root nodules leads to the development of a novel organelle known as the "symbiosome," which houses the endosymbiotic rhizobia bacteroids. In mature nodules, the host infected cells are occupied by thousands of symbiosomes, which constitute the major organelle within this specialized cell type. The symbiosome is delimited by the symbiosome membrane (SM), 2 which controls the transport of all metabolites between the symbiont and the plant host. These transport activities include the efflux of the primary metabolic product of nitrogen fixation (NH 3 /NH 4 ϩ ) and the uptake of dicarboxylates as an energy source to support bacterial N 2 fixation (1, 2). Because of the unique role of the SM, a number of host nodulin ("noduleenhanced") proteins are synthesized and localized to this membrane (3, 4), where they serve transport and regulatory functions in the symbiosis.Early studies revealed that nodulin 26 (nod26), a member of the major intrinsic protein (MIP)/aquaporin superfamily, is among the ensemble of soybean SM nodulins produced during symbiosome biogenesis (4 -7). Since the original identification of nod26 over 20 years ago (4), the role of this channel in the symbiosis has been debated. Functional analyses show that nod26 is a multifunctional "aquaglyceroporin" that transports multiple substrates including water, formamide, and glycerol (6, 8). As a symbiosome-specific aquaglyceroporin, nod26 has been proposed to serve as a low energy transport pathway for water as well as osmolytes within the inf...

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Interaction of Cytosolic Glutamine Synthetase of Soybean Root Nodules with the C-terminal Domain of the Symbiosome Membrane Nodulin 26 Aquaglyceroporin

Masalkar

Wallace

Hwang

et al. 2010

Journal of Biological Chemistry

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“…3D). Post-translational regulation by a 14-3-3 protein has previously been reported to play a positive role in GS activation (Finnemann and Schjoerring, 2000;Lima et al, 2006).…”

Section: Responses Of Gs Protein and Activity To High Ammonium Levelsmentioning

confidence: 99%

Cytosolic Glutamine Synthetase Gln1;2 Is the Main Isozyme Contributing to GS1 Activity and Can Be Up-Regulated to Relieve Ammonium Toxicity

et al. 2016

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Cytosolic GS1 (Gln synthetase) is central for ammonium assimilation in plants. High ammonium treatment enhanced the expression of the GS1 isogene Gln-1;2 encoding a low-affinity high-capacity GS1 protein in Arabidopsis (Arabidopsis thaliana) shoots. Under the same conditions, the expression of the high-affinity low-capacity isoform Gln-1;1 was reduced. The expression of Gln-1;3 did not respond to ammonium treatment while Gln-1;4 and Gln-1;5 isogenes in all cases were expressed at a very low level. Gln-2 was highly expressed in shoots but only at a very low level in roots. To investigate the specific functions of the two isogenes Gln-1;1 and Gln-1;2 in shoots for ammonium detoxification, single and double knock-out mutants were grown under standard N supply or with high ammonium provision. Phenotypes of the single mutant gln1;1 were similar to the wild type, while growth of the gln1;2 single mutant and the gln1;1:gln1;2 double mutant was significantly impaired irrespective of N regime. GS1 activity was significantly reduced in both gln1;2 and gln1;1:gln1;2. Along with this, the ammonium content increased while that of Gln decreased, showing that Gln-1;2 was essential for ammonium assimilation and amino acid synthesis. We conclude that Gln-1;2 is the main isozyme contributing to shoot GS1 activity in vegetative growth stages and can be up-regulated to relieve ammonium toxicity. This reveals, to our knowledge, a novel shoot function of Gln-1;2 in Arabidopsis shoots.

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“…Changes in MDA content were observed in the tomato seedlings treated with different concentrations of Pb +2 , indicating that the samples were under stress. It has been demonstrated that increased lipid peroxidation is a characteristic feature of oxidative stress caused by unbalanced equilibrium between ROS production and scavenging or defense mechanisms under heavy metal stress (Smirnoff 1993;Mittler 2002;Lima et al 2006).…”

Section: +2mentioning

confidence: 99%

Effects of lead (PB) and cadmium (CD) elements on lipid peroxidation, catalase enzyme activity and catalase gene expression profile in tomato plants

AYDIN¹,

BÜYÜK²,

İlker;³

et al. 2016

Tarım Bilimleri Dergisi

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Heavy metals are significant abiotic stress factor, affecting various response mechanisms in plants. These responses include: changes in membrane composition, production of small molecules and free radicals, and alterations in the activities of antioxidant enzymes and their gene expressions. For this reason, lipid peroxidation levels (MDA), catalase enzyme activity, and gene expression profiles, quantified by real-time PCR, were analyzed in tomato plants exposed to various concentrations (0, 80, 160, 320, 640 and 1280 μM) of Cd 2+ and Pb 2+ . All concentration of Cd +2 or Pb +2 contamination led to increased lipid peroxidation and catalase enzyme activity, except for 320 and 640 μM Cd +2 contamination levels. As a result, gene expression patterns at the mRNA level and changes in MDA content under different concentrations of Pb +2 and Cd +2 contamination revealed a positive correlation, although no correlation was found between gene expression patterns at the mRNA level and catalase enzyme activity. These results might be explained by the regulation of genes at the transcriptional, posttranscriptional, and also translational or posttranslational levels.

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Phosphorylation and subsequent interaction with 14-3-3 proteins regulate plastid glutamine synthetase in Medicago truncatula

Cited by 57 publications

References 44 publications

Interaction of Cytosolic Glutamine Synthetase of Soybean Root Nodules with the C-terminal Domain of the Symbiosome Membrane Nodulin 26 Aquaglyceroporin

Interaction of Cytosolic Glutamine Synthetase of Soybean Root Nodules with the C-terminal Domain of the Symbiosome Membrane Nodulin 26 Aquaglyceroporin

Cytosolic Glutamine Synthetase Gln1;2 Is the Main Isozyme Contributing to GS1 Activity and Can Be Up-Regulated to Relieve Ammonium Toxicity

Effects of lead (PB) and cadmium (CD) elements on lipid peroxidation, catalase enzyme activity and catalase gene expression profile in tomato plants

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