The high turnover Drosophila multidrug resistance-associated protein shares the biochemical features of its human orthologues

Biochim Biophys Acta. 2009 Feb;1788(2):402-9. doi: 10.1016/j.bbamem.2008.11.007. Epub 2008 Nov 20.

Abstract

DMRP, an ABC transporter encoded by the dMRP/CG6214 gene, is the Drosophila melanogaster orthologue of the "long" human multidrug resistance-associated proteins (MRP1/ABCC1, MRP2/ABCC2, MRP3/ABCC3, MRP6/ABCC6, and MRP7/ABCC10). In order to provide a detailed biochemical characterisation we expressed DMRP in Sf9 insect cell membranes. We demonstrated DMRP as a functional orthologue of its human counterparts capable of transporting several human MRP substrates like beta-estradiol 17-beta-D-glucuronide, leukotriene C4, calcein, fluo3 and carboxydichlorofluorescein. Unexpectedly, we found DMRP to exhibit an extremely high turnover rate for the substrate transport as compared to its human orthologues. Furthermore, DMRP showed remarkably high basal ATPase activity (68-75 nmol Pi/mg membrane protein/min), which could be further stimulated by probenecid and the glutathione conjugate of N-ethylmaleimide. Surprisingly, this high level basal ATPase activity was inhibited by the transported substrates. We discussed this phenomenon in the light of a potential endogenous substrate (or activator) present in the Sf9 membrane.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphatases / metabolism
  • Adenosine Triphosphate / metabolism
  • Animals
  • Biological Transport
  • Cell Line
  • Drosophila melanogaster / chemistry*
  • Drosophila melanogaster / genetics
  • Drosophila melanogaster / metabolism*
  • Humans
  • Multidrug Resistance-Associated Proteins / chemistry*
  • Multidrug Resistance-Associated Proteins / genetics
  • Multidrug Resistance-Associated Proteins / metabolism*
  • Spodoptera
  • Substrate Specificity

Substances

  • Multidrug Resistance-Associated Proteins
  • Adenosine Triphosphate
  • Adenosine Triphosphatases