Degradation of glutathione <i>S</i>‐conjugates by a carboxypeptidase in the plant vacuole

Wolf, Andreas; Dietz, Karl‐Josef; Schröder, Peter

doi:10.1016/0014-5793(96)00272-4

Cited by 144 publications

(91 citation statements)

References 12 publications

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“…In situ cytosolic glutathionation of monochlorobimane to its fluorescent derivative, bimane-GS, and accumulation of the latter in the vacuoles of protoplasts and cell suspension cultures has been demonstrated (37) as has a greater than 50-fold accumulation of alachor-GS in the vacuoles of intact barley leaves (38). Likewise, it is evident that an MRP-like functionality is responsible for the vacuolar uptake of both glutathionated and nonglutathionated dyes by barley aleurone cells (39).…”

Section: Discussionmentioning

confidence: 99%

Enhanced Multispecificity of Arabidopsis Vacuolar Multidrug Resistance-associated Protein-type ATP-binding Cassette Transporter, AtMRP2

Liu

Sánchez-Fernández

et al. 2001

Journal of Biological Chemistry

133

117

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Recent investigations have established thatArabidopsis thaliana contains a family of genes encoding ATPbinding cassette transporters belonging to the multidrug resistance-associated protein (MRP) family. So named because of the phenotypes conferred by their animal prototypes, many MRPs are MgATP-energized pumps active in the transport of glutathione (GS) conjugates and other bulky amphipathic anions across membranes. Here we show that Arabidopsis MRP2 (At-MRP2) localizes to the vacuolar membrane fraction from seedlings and is not only competent in the transport of GS conjugates but also glucuronate conjugates after heterologous expression in yeast. Based on the stimulatory action of the model GS conjugate 2,4-dinitrophenyl-GS (DNP-GS) on uptake of the model glucuronide 17␤-estradiol 17-(␤-D-glucuronide) (E 2 17␤G) and vice versa, double-label experiments demonstrating that the two substrates are subject to simultaneous transport by AtMRP2 and preloading experiments suggesting that the effects seen result from cis, not trans, interactions, it is inferred that some GS conjugates and some glucuronides reciprocally activate each other's transport via distinct but coupled binding sites. The results of parallel experiments on AtMRP1 and representative yeast and mammalian MRPs indicate that these properties are specific to AtMRP2. The effects exerted by DNP-GS on AtMRP2 are not, however, common to all GS conjugates and not simulated by oxidized glutathione or reduced glutathione. Decyl-GS, metolachlor-GS, and oxidized glutathione, although competitive with DNP-GS, do not promote E 2 17␤G uptake by AtMRP2. Reduced glutathione, although subject to transport by AtMRP2 and able to markedly promote E 2 17␤G uptake, neither competes with DNP-GS for uptake nor is subject to E 2 17␤G-promoted uptake. A multisite model comprising three or four semi-autonomous transport pathways plus distinct but tightly coupled binding sites is invoked for AtMRP2. ATP-binding cassette (ABC)1 transporters are starting to assume prominence in considerations of energy-dependent transport in plants. Constituted of one or two copies each of two core structural elements: a hydrophobic, membrane spanning domain (MSD) containing multiple (usually four or six) transmembrane spans and a cytosolically oriented ATP-binding domain (nucleotide binding fold, NBF) containing Walker A, Walker B, and ABC signature sequence motifs, ABC transporters are MgATP-energized pumps that as a superfamily are active in the transport of a broad range of substances including alkaloids, amino acids, sugars and sugar conjugates, peptides and peptide conjugates, heavy metal chelates, and lipids across membranes (1).Two classes of findings were instrumental in prompting studies of ABC transporters in plants. The first was the molecular cloning of a multidrug resistance (MDR)-like gene from Arabidopsis thaliana (2) and the subsequent independent isolation of other MDR homologs from the same and other plant species (3, 4). Because all of these genes encode ABC transporters bearing...

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Section: Discussionmentioning

confidence: 99%

Enhanced Multispecificity of Arabidopsis Vacuolar Multidrug Resistance-associated Protein-type ATP-binding Cassette Transporter, AtMRP2

Liu

Sánchez-Fernández

et al. 2001

Journal of Biological Chemistry

133

117

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“…SCPL enzymes also play a role in herbicide metabolism, in which a SCPL has been shown to catalyze the first step in the catabolism of an alachlor glutathione S-conjugate by removing the terminal glycine residue of the glutathione moiety (Wolf et al, 1996). On the basis of these and other studies, investigators have suggested various functions for SCPL enzymes, ranging from protein turnover and C-terminal processing to roles in wound responses and xenobiotic metabolism.…”

Section: Discussionmentioning

confidence: 99%

Cloning of the SNG1 Gene of Arabidopsis Reveals a Role for a Serine Carboxypeptidase-like Protein as an Acyltransferase in Secondary Metabolism

et al. 2000

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Serine carboxypeptidases contain a conserved catalytic triad of serine, histidine, and aspartic acid active-site residues. These enzymes cleave the peptide bond between the penultimate and C-terminal amino acid residues of their protein or peptide substrates. The Arabidopsis Genome Initiative has revealed that the Arabidopsis genome encodes numerous proteins with homology to serine carboxypeptidases. Although many of these proteins may be involved in protein turnover or processing, the role of virtually all of these serine carboxypeptidase-like (SCPL) proteins in plant metabolism is unknown. We previously identified an Arabidopsis mutant, sng1 (sinapoylglucose accumulator 1), that is defective in synthesis of sinapoylmalate, one of the major phenylpropanoid secondary metabolites accumulated by Arabidopsis and some other members of the Brassicaceae. We have cloned the gene that is defective in sng1 and have found that it encodes a SCPL protein. Expression of SNG1 in Escherichia coli demonstrates that it encodes sinapoylglucose:malate sinapoyltransferase, an enzyme that catalyzes a transesterification instead of functioning like a hydrolase, as do the other carboxypeptidases. This finding suggests that SCPL proteins have acquired novel functions in plant metabolism and provides an insight into the evolution of secondary metabolic pathways in plants. INTRODUCTIONPlants produce thousands of unique molecules that are collectively referred to as secondary metabolites. Even within the angiosperms, many of these compounds are unique to specific taxa, indicating that the pathways that produce them may have evolved within the last 100,000 years. A central question in the study of plant secondary metabolism concerns how the catalytic diversity of plant secondary metabolism has arisen. What classes of genes and proteins have been co-opted, presumably from their ancestral roles in primary metabolism, to serve as catalysts in the synthesis of secondary metabolites?In Arabidopsis, the phenylpropanoid pathway leads to the production of sinapic acid esters, a group of fluorescent UVprotective secondary metabolites derived from phenylalanine (Figure 1). These compounds are dispensable under laboratory conditions and thus provide targets for the genetic dissection of phenylpropanoid metabolism. The analysis of these compounds is facilitated by their blue fluorescence under UV light both in vivo and after thin-layer chromatography (TLC) (Chapple et al., 1992;Ruegger et al., 1999). Arabidopsis and some other members of the Brassicaceae accumulate three major sinapic acid esters. In the biosynthetic pathway leading to these compounds, sinapoylglucose is the immediate precursor of sinapoylcholine and sinapoylmalate, which accumulate in seeds and leaves, respectively. 1-O -Sinapoylglucose is a ␤ -acetal ester with a high free energy of hydrolysis (Mock and Strack, 1993); it provides the necessary free energy for the transacylation reaction catalyzed by sinapoylglucose:malate sinapoyltransferase (SMT; EC 2.3.1.92) (Strack, 1982), which ...

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“…Finally, safener-inducible genes for serine carboxypeptidase and a lactoylglutathione lyase (carbon-sulfur lyase) family protein may be involved in phase IV of the detoxification process (Table 2). Serine carboxypeptidase contributes to the degradation of GSH conjugates to their respective Cys derivatives (Wolf, Dietz & Schroder 1996), which may be further metabolized by carbon-sulfur lyases (Brazier-Hicks et al 2008). It thus seems that the entire xenobiotic detoxification machinery is induced at the transcript level after safener treatment in aerial tissues of Arabidopsis, confirming previous conclusions that it is not safener inducibility per se that distinguishes monocots and dicots with respect to safener efficacy.…”

Section: Safeners Induce the Expression Of The Endogenous Detoxificatmentioning

confidence: 99%

Safeners recruit multiple signalling pathways for the orchestrated induction of the cellular xenobiotic detoxification machinery in Arabidopsis

Behringer

Bartsch

Schaller

2011

Plant Cell & Environment

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Safeners enhance herbicide tolerance in crop plants but not in target weeds, thus improving herbicide selectivity. The safeners isoxadifen-ethyl and mefenpyr-diethyl protect cereal crops from sulfonyl urea herbicides in postemergence application. The two safeners were shown here to induce the cellular xenobiotic detoxification machinery in Arabidopsis thaliana when applied to leaves in a way mimicking field application. Gene expression profiling revealed the induction of 446 genes potentially involved in the detoxification process. Transgenic Arabidopsis plants expressing a reporter gene under control of a safenerresponsive maize promoter were used as a model system to study the safener signalling pathway. Reporter gene analysis in the tga2/3/5/6, sid2-2 and npr1 mutants as compared with the wild-type background showed that safener inducibility required TGA transcription factors and salicylic acid (SA) in a NON-EXPRESSOR of PR-1 (NPR1)-independent pathway converging on two as-1 promoter elements. For the majority of the safener-responsive Arabidopsis genes, a similar dependence on TGA transcription factors and/or SA was shown by gene expression profiling in wild-type plants as compared with the tga2/3/5/6 and sid2-2 mutants. Thirty-eight percent of the genes, however, were induced by safeners in a TGA/SA-independent manner. These genes are likely to be controlled by WRKY transcription factors and cognate W-boxes in their promoters.

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Degradation of glutathione S‐conjugates by a carboxypeptidase in the plant vacuole

Cited by 144 publications

References 12 publications

Enhanced Multispecificity of Arabidopsis Vacuolar Multidrug Resistance-associated Protein-type ATP-binding Cassette Transporter, AtMRP2

Enhanced Multispecificity of Arabidopsis Vacuolar Multidrug Resistance-associated Protein-type ATP-binding Cassette Transporter, AtMRP2

Cloning of the SNG1 Gene of Arabidopsis Reveals a Role for a Serine Carboxypeptidase-like Protein as an Acyltransferase in Secondary Metabolism

Safeners recruit multiple signalling pathways for the orchestrated induction of the cellular xenobiotic detoxification machinery in Arabidopsis

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