Characterization of the MRP4- and MRP5-mediated transport of cyclic nucleotides from intact cells.

Pieter Wielinga, Ingrid van der Heijden, Glen Reid, Jos H. Beijnen, Jan Wijnholds, Piet Borst

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Cyclic nucleotides are known to be effluxed from cultured cells or isolated tissues. Two recently described members of the multidrug resistance protein family, MRP4 and MRP5, might be involved in this process, because they transport the 3',5'-cyclic nucleotides, cAMP and cGMP, into inside-out membrane vesicles. We have investigated cGMP and cAMP efflux from intact HEK293 cells overexpressing MRP4 or MRP5. The intracellular production of cGMP and cAMP was stimulated with the nitric oxide releasing compound sodium nitroprusside and the adenylate cyclase stimulator forskolin, respectively. MRP4- and MRP5-overexpressing cells effluxed more cGMP and cAMP than parental cells in an ATP-dependent manner. In contrast to a previous report we found no glutathione requirement for cyclic nucleotide transport. Transport increased proportionally with intracellular cyclic nucleotide concentrations over a calculated range of 20-600 muM, indicating low affinity transport. In addition to several classic inhibitors of organic anion transport, prostaglandins A1 and E1, the steroid progesterone and the anti-cancer drug estramustine all inhibited cyclic nucleotide efflux. The afflux mediated by MRP4 and MRP5 did not lead to a proportional decrease in the intracellular cGMP or cAMP levels but reduced cGMP by maximally 2-fold over the first hour. This was also the case when phosphodiesterase-mediated cyclic nucleotide hydrolysis was inhibited by 3-isobutyl-1-methylxanthine, conditions in which efflux was maximal. These data indicate that MRP4 and MRP5 are low affinity cyclic nucleotide transporters that may at best function as overflow pumps, decreasing steep increases in cGMP levels under conditions where cGMP synthesis is strongly induced and phosphodiesterase activity is limiting.
Original languageEnglish
JournalJournal of Biological Chemistry
Volume278
Issue number20
Pages (from-to)17664-17671
ISSN0021-9258
DOIs
Publication statusPublished - 2003
Externally publishedYes

Keywords

  • Primates Mammalia Vertebrata Chordata Animalia (Animals, Chordates, Humans, Mammals, Primates, Vertebrates) - Hominidae [86215] HEK293 cell line cell line human embryonic kidney cells
  • 3-isobutyl-1-methylxanthine 28822-58-4
  • cyclic AMP 60-92-4
  • cyclic GMP 7665-99-8
  • forskolin 66575-29-9 adenylate cyclase stimulator
  • MRP4 multidrug resistance protein 4 expression
  • MRP5 multidrug resistance protein 5 expression
  • sodium nitroprusside 14402-89-2
  • 02502, Cytology - General
  • 02508, Cytology - Human
  • 10060, Biochemistry studies - General
  • 10062, Biochemistry studies - Nucleic acids, purines and pyrimidines
  • 13002, Metabolism - General metabolism and metabolic pathways
  • Biochemistry and Molecular Biophysics
  • Cell Biology
  • Metabolism

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