An NADP/thioredoxin system in leaves: Purification and characterization of NADP-thioredoxin reductase and thioredoxin h from spinach

Florencio, Francisco J.; Yee, Boihon C.; Johnson, Thomas C.; Buchanan, Bob B.

doi:10.1016/0003-9861(88)90282-2

Cited by 134 publications

(75 citation statements)

References 21 publications

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“…Plant h-TRXs have long been considered soluble proteins due to the lack of transit peptides (Florencio et al, 1988). In the case of the subgroup 2 members, only a couple of localization experiments have been reported.…”

Section: H-trxs Of Subgroup 2 Are Specifically Localized To the Er/gomentioning

confidence: 99%

Roles of N-Terminal Fatty Acid Acylations in Membrane Compartment Partitioning:Arabidopsis h-Type Thioredoxins as a Case Study

et al. 2013

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N-terminal fatty acylations (N-myristoylation [MYR] and S-palmitoylation [PAL]) are crucial modifications affecting 2 to 4% of eukaryotic proteins. The role of these modifications is to target proteins to membranes. Predictive tools have revealed unexpected targets of these acylations in Arabidopsis thaliana and other plants. However, little is known about how N-terminal lipidation governs membrane compartmentalization of proteins in plants. We show here that h-type thioredoxins (h-TRXs) cluster in four evolutionary subgroups displaying strictly conserved N-terminal modifications. It was predicted that one subgroup undergoes only MYR and another undergoes both MYR and PAL. We used plant TRXs as a model protein family to explore the effect of MYR alone or MYR and PAL in the same family of proteins. We used a high-throughput biochemical strategy to assess MYR of specific TRXs. Moreover, various TRX-green fluorescent protein fusions revealed that MYR localized protein to the endomembrane system and that partitioning between this membrane compartment and the cytosol correlated with the catalytic efficiency of the N-myristoyltransferase acting at the N terminus of the TRXs. Generalization of these results was obtained using several randomly selected Arabidopsis proteins displaying a MYR site only. Finally, we demonstrated that a palmitoylatable Cys residue flanking the MYR site is crucial to localize proteins to micropatching zones of the plasma membrane.

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Section: H-trxs Of Subgroup 2 Are Specifically Localized To the Er/gomentioning

confidence: 99%

Roles of N-Terminal Fatty Acid Acylations in Membrane Compartment Partitioning:Arabidopsis h-Type Thioredoxins as a Case Study

et al. 2013

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“…Escherichia coli thioredoxin and NTR were purchased from American Diagnostica, Inc. (Greenwich, CT). Wheat thioredoxin h and NTR were isolated from wheat germ, following the procedures developed for spinach leaves (8). E. coli glutaredoxin was a kind gift of Professor A. Holmgren.…”

Section: Reagents/fine Chemicalsmentioning

confidence: 99%

Specific reduction of wheat storage proteins by thioredoxin h.

Kobrehel¹,

Wong²,

Balogh³

et al. 1992

Plant Physiol.

186

129

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Gliadins and glutenins, the major storage proteins of wheat endosperm (Triticum durum, Desf. cv Monroe), were reduced in vitro by the NADP/thioredoxin system (NADPH, NADP-thioredoxin reductase and thioredoxin; in plants, the h type) from either the same source or the bacterium Escherichia coli. A more limited reduction of certain members of these protein groups was achieved with the reduced form of glutathione or glutaredoxin, a protein known to replace thioredoxin in certain bacterial and mammalian enzyme systems but not known to occur in higher plants. Endo The seed is the only tissue for which the NADP/thioredoxin system has been ascribed physiological activity in plants. Thioredoxin h reduces members of several different soluble seed proteins-thionins, a-amylase, and trypsin inhibitors (11, 14)-and also reductively activates an enzyme of carbohydrate metabolism (PPi fructose-6-P, 1-phosphotransferase, or PFP) (13). The results (14) suggest that the inhibitor proteins, long known to be active in bioprotection, may function within the seed to link thioredoxin to the regulation of yet-to-be identified target enzymes (cf. 9, 16, 21).The question arises as to whether thioredoxin can reduce other types of seed proteins. Quantitatively, the most important group is comprised of storage proteins, which account for up to 80% of the total protein of the seed (12,20). In the case of plants such as cereals, these proteins are insoluble in aqueous solutions and are chemically inert until they are reduced. It is not known how these proteins are mobilized during germination, and a physiological agent capable of their reduction has not been described.To help fill this gap, we have undertaken a study with wheat, a cereal with well-characterized seed proteins. We now report that representatives of the major wheat (Triticum durum) storage proteins-the gliadins and glutenins-are specifically reduced by thioredoxin. The results provide evidence that the NADP/thioredoxin system functions in the reduction of the principal seed proteins, thereby increasing their proteolytic susceptibility and making amino acids (nitrogen and sulfur) available during germination. Taken together with our recent work (14), the new findings suggest that thioredoxin functions as a signal to enhance metabolic processes associated with seed germination. A preliminary account of this work has been published (31). MATERIALS AND METHODS Plant MaterialSeeds and semolina of durum wheat (Triticum durum, Desf. cv Monroe) were kind gifts of Dr. K. Kahn. Germination of Wheat SeedsTwenty to thirty seeds were placed in a plastic Petri dish on three layers of Whatman No. 1 filter paper moistened with 5 mL of deionized water. Germination was carried out for up to 4 d at room temperature in a dark chamber. Plant Physiol. Vol. 99, 1992 Reagents/Fine Chemicals Biochemicals and lyophilized coupling enzymes were obtained from Sigma. Escherichia coli thioredoxin and NTR were purchased from American Diagnostica, Inc. (Greenwich, CT). Wheat thioredoxin h and NTR w...

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“…In addition, they have been related to Met metabolism (Mouaheb et al, 1998) and the response against biotic and abiotic stress (Mouaheb et al, 1998;Reichheld et al, 2002;Serrato and Cejudo, 2003;Laloi et al, 2004), this latter function not being well known yet. Type-h TRXs are generally assumed to be cytosolic proteins because of their lack of transit peptide (Florencio et al, 1988), but other subcellular locations have been proposed (Gelhaye et al, 2004a). They have also been described as an abundant protein in rice phloem sap (Ishiwatari et al, 1995;Schobert et al, 1998) where they are able to move between the sieve tube and nearby cells via plasmodesmata (Ishiwatari et al, 1998).…”

mentioning

confidence: 99%

PsTRXh1 and PsTRXh2 Are Both Pea h-Type Thioredoxins with Antagonistic Behavior in Redox Imbalances

et al. 2006

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An NADP/thioredoxin system in leaves: Purification and characterization of NADP-thioredoxin reductase and thioredoxin h from spinach

Cited by 134 publications

References 21 publications

Roles of N-Terminal Fatty Acid Acylations in Membrane Compartment Partitioning:Arabidopsis h-Type Thioredoxins as a Case Study

Roles of N-Terminal Fatty Acid Acylations in Membrane Compartment Partitioning:Arabidopsis h-Type Thioredoxins as a Case Study

Specific reduction of wheat storage proteins by thioredoxin h.

PsTRXh1 and PsTRXh2 Are Both Pea h-Type Thioredoxins with Antagonistic Behavior in Redox Imbalances

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