Title
Transport of glutathione A conjugates by the multifrug resistance protein 1
Author
Centraal Instituut voor Voedingsonderzoek TNO TNO Voeding
Evers, R.
Cnubben, N.H.P.
Wijnholds, J.
van Deemter, L.
van Bladeren, P.J.
Borst, P.
Publication year
1997
Abstract
The human multidrug resistance protein MRP1 mediates transport of organic substrates conjugated to glutathione, glucuronide, or sulfate. The naturally occurring prostaglandins A1 and A2 can form two diastereomeric glutathione S-conjugates, and it has been speculated that these might be substrates for MRP1. Here we present evidence that polarized MDCKII cells expressing MRP1 cDNA transport PGA1-GS to the basolateral side of a cell monolayer, in accordance with the lateral localization of human MRP1 in these cells. Furthermore, we show that vesicles made from yeast cells expressing MRP1 cDNA and from mouse erythrocytes (known to contain mrp1) actively accumulate both diastereomers of PGA2-GS with a similar efficiency. Recently, we generated mice with a homozygous mutant mrp1 allele. Uptake of PGA2-GS in vesicles made from erythrocytes of these mice was 3.2 times lower than in wild-type vesicles, but was still significantly above background. This residual transport activity was partly inhibited by methotrexate and cAMP, whereas mrp1-mediated activity was unaffected by these compounds. We conclude that mouse erythrocytes contain at least two transport systems for PGA2-GS. One of these is mrp1; the other one has not been identified yet, but can be inhibited by methotrexate and cAMP.
Subject
GS-X pump
Multidrug resistance
Adenosine Triphosphate
Animals
Biological Transport
Cell Line
Cell Polarity
Cyclic AMP
Dogs
Erythrocytes
Ethacrynic Acid
Glutathione
Humans
Kidney
Methotrexate
Mice
Mice, Mutant Strains
Microsomes
P-Glycoprotein
Prostaglandins A, Synthetic
Stereoisomerism
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http://resolver.tudelft.nl/uuid:96260aff-15d4-4524-ab0b-dea8a1390f71
TNO identifier
39725
Source
Febs Letters, 419 (419), 112-116
Document type
article