[11] Arabidopsis MDR genes: Molecular cloning and protein chemical aspects

Dudler, Robert; Sidler, Michael

doi:10.1016/s0076-6879(98)92013-4

Cited by 9 publications

(5 citation statements)

References 16 publications

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“…The AtPGP1 clone exhibited similar intron structure to mammalian MDR genes, and encoded a protein with similar organisation of structural domains, suggesting that the P-gp subfamily evolved prior to the divergence of plants and animals [13]. Southern blot analysis of AtPGP1 revealed the existence of a second, diverged member of the gene family; subsequently, a second homologue, AtPGP2, was cloned [13,16]. AtPGP1 and 2 share 44% amino acid identity, and are each 42% identical to human MDR1 [16].…”

Section: Molecular Cloning Of Plant P-gp Homologuesmentioning

confidence: 97%

“…It is this signature motif which distinguishes ABC transporters from other NTP binding proteins, such as kinases, which also contain the Walker sequences [14,15]. Sequence homology over the whole gene can be negligible between di¡erent ABC transporters, but in the conserved areas of the NBF it is typically 30^40% between family members, and this has proved useful in the isolation of ABC genes by ap-proaches such as PCR and hybridisation with degenerate nucleotides [16].…”

Section: Domain Organisationmentioning

confidence: 99%

“…Southern blot analysis of AtPGP1 revealed the existence of a second, diverged member of the gene family; subsequently, a second homologue, AtPGP2, was cloned [13,16]. AtPGP1 and 2 share 44% amino acid identity, and are each 42% identical to human MDR1 [16]. Further similar, but non-identical MDR-like Arabidopsis genes have also been reported, though their sequences are not yet publicly available ( [5]; Rea et al, unpublished results).…”

Section: Molecular Cloning Of Plant P-gp Homologuesmentioning

confidence: 99%

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Plant ABC transporters

Theodoulou

2000

Biochimica et Biophysica Acta (BBA) - Biomembranes

237

142

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The ATP binding cassette (ABC) superfamily is a large, ubiquitous and diverse group of proteins, most of which mediate transport across biological membranes. ABC transporters have been shown to function not only as ATP-dependent pumps, but also as ion channels and channel regulators. Whilst members of this gene family have been extensively characterised in mammalian and microbial systems, the study of plant ABC transporters is a relatively new field of investigation. Sequences of over 20 plant ABC proteins have been published and include homologues of P-glycoprotein, MRP, PDR5 and organellar transporters. At present, functions have been assigned to a small proportion of these genes and only the MRP subclass has been extensively characterised. This review aims to summarise literature relevant to the study of plant ABC transporters, to review methods of cloning, to discuss the utility of yeast and mammalian systems as models and to speculate on possible roles of uncharacterised ABC transporters in plants.

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Section: Molecular Cloning Of Plant P-gp Homologuesmentioning

confidence: 97%

Section: Domain Organisationmentioning

confidence: 99%

Section: Molecular Cloning Of Plant P-gp Homologuesmentioning

confidence: 99%

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Plant ABC transporters

Theodoulou

2000

Biochimica et Biophysica Acta (BBA) - Biomembranes

237

142

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“…Although several plant MDRs and their close relatives the pleiotropic drug resistance proteins have been cloned in their entirety (2)(3)(4)9), the transport capabilities of the proteins encoded by these genes has eluded definition. AtPGP1, for instance, is the most thoroughly characterized MDR from a plant source, and elegant investigations of transgenic plants have shown this ABC transporter to be a plasma membrane protein involved in light-dependent hypocotyl elongation (10,11), but its mode of action remains obscure.…”

mentioning

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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“…Therefore, MDR transporters are currently considered as a major element in the mechanism of chemoimmunity [ 7 ]. Moreover, MDR proteins are ubiquitous, belonging to the evolutionarily conserved family of the ATP-binding cassette (ABC) proteins found in most living organisms, from bacteria [ 8 ], parasites [ 9 , 10 ], free-living protozoa [ 11 , 12 ], aquatic invertebrates and fish [ 5 , 13 , 14 , 15 ], Drosophila [ 16 , 17 ], plants [ 18 , 19 ] to mammals [ 7 ]. In man, the three principal types of MDR proteins identified are: (i) Permeability glycoprotein (P-gp) encoded by ABCB1 or MDR1 gene; (ii) MDR-associated protein (MRP) encoded by ABCC genes ( ABCC1 , ABCC2 , plus probably ABCC3-6 and ABCC10-11 ); (iii) Breast Cancer Resistance Protein (BCRP) encoded by ABCG2 gene.…”

Section: Introductionmentioning

confidence: 99%

Mini-P-gp and P-gp Co-Expression in Brown Trout Erythrocytes: A Prospective Blood Biomarker of Aquatic Pollution

et al. 2015

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In aquatic organisms, such as fish, blood is continually exposed to aquatic contaminants. Multidrug Resistance (MDR) proteins are ubiquitous detoxification membrane pumps, which recognize various xenobiotics. Moreover, their expression is induced by a large class of drugs and pollutants. We have highlighted the co-expression of a mini P-gp of 75 kDa and a P-gp of 140 kDa in the primary culture of brown trout erythrocytes and in the erythrocytes of wild brown trout collected from three rivers in the Auvergne region of France. In vitro experiments showed that benzo[a]pyrene, a highly toxic pollutant model, induced the co-expression of mini-P-gp and P-gp in trout erythrocytes in a dose-dependent manner and relay type response. Similarly, in the erythrocytes of wild brown trout collected from rivers contaminated by a mixture of PAH and other multi-residues of pesticides, mini-P-gp and P-gp were able to modulate their expression, according to the nature of the pollutants. The differential and complementary responses of mini-P-gp and P-gp in trout erythrocytes suggest the existence in blood cells of a real protective network against xenobiotics/drugs. This property could be exploited to develop a blood biomarker of river pollution.

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[11] Arabidopsis MDR genes: Molecular cloning and protein chemical aspects

Cited by 9 publications

References 16 publications

Plant ABC transporters

Plant ABC transporters

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

Mini-P-gp and P-gp Co-Expression in Brown Trout Erythrocytes: A Prospective Blood Biomarker of Aquatic Pollution

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