S-decyl-glutathione nonspecifically stimulates the ATPase activity of the nucleotide-binding domains of the human multidrug resistance-associated protein, MRP1 (ABCC1).
The human multidrug resistance-associated protein(MRP1) is an ATP-dependent efflux pump that transports anionic conjugates, and hydrophobic compounds in a glutathione dependent manner. Similar to the other, well-characterized multidrug transporter P-gp, MRP1 comprises two nucleotide-binding domains (NBDs) in addition to transmembrane domains. However, whereas the NBDs of P-gp have been shown to be functionally equivalent, those of MRP1 differ significantly. The isolated NBDs of MRP1 have been characterized in Escherichia coli as fusions with either the glutathione-S-transferase (GST) or the maltose-binding domain (MBP). The nonfused NBD1 was obtained by cleavage of the fusion protein with thrombin. The GST-fused forms of NBD1 and NBD2 hydrolyzed ATP with an apparent K(m) of 340 microm and a V(max) of 6.0 nmol P(I) x mg-1 x min-1, and a K(m) of 910 microm ATP and a V(max) of 7.5 nmol P(I) x mg-1 x min-1, respectively. Remarkably, S-decyl-glutathione, a conjugate specifically transported by MRP1 and MRP2, was able to stimulate the ATPase activities of the isolated NBDs more than 2-fold in a concentration-dependent manner. However,the stimulation of the ATPase activity was found to coincide with the formation of micelles by S-decyl-glutathione. Equivalent stimulation of ATPase activity could be obtained by surfactants with similar critical micelle concentrations.
Department of Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Haren, The Netherlands. r.h.cool@farm.rug.nl
Robbert H
RH
Cool
Marloes K
MK
Veenstra
Wim
W
van Klompenburg
René I R
RI
Heyne
Michael
M
Müller
Elisabeth G E
EG
de Vries
Hendrik W
HW
van Veen
Wil N
WN
Konings
D018528:ATP-Binding Cassette Transporters / Q000187:drug effects* / Q000378:metabolism; D000251:Adenosine Triphosphatases / Q000187:drug effects* / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism*; D001665:Binding Sites; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D005978:Glutathione / Q000031:analogs & derivatives / Q000494:pharmacology*; D006801:Humans; D007700:Kinetics; D008823:Micelles; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000737:chemistry / Q000187:drug effects* / Q000235:genetics; D010446:Peptide Fragments / Q000187:drug effects / Q000378:metabolism; D017434:Protein Structure, Tertiary / Q000187:drug effects; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013501:Surface-Active Agents / Q000494:pharmacology*
D018528:ATP-Binding Cassette Transporters; D000251:Adenosine Triphosphatases; D000255:Adenosine Triphosphate; D005978:Glutathione; D008823:Micelles; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins; D013501:Surface-Active Agents; C465222:S-decylglutathione; C421109:multidrug resistance-associated protein 1