RGD Reference Report - Transport function and hepatocellular localization of mrp6 in rat liver. - Rat Genome Database
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Transport function and hepatocellular localization of mrp6 in rat liver.

Authors: Madon, J  Hagenbuch, B  Landmann, L  Meier, PJ  Stieger, B 
Citation: Madon J, etal., Mol Pharmacol 2000 Mar;57(3):634-41.
RGD ID: 1549867
Pubmed: (View Article at PubMed) PMID:10692506

The multidrug resistance-associated proteins (Mrps) constitute a family of cellular export pumps of the ATP-binding cassette transporter superfamily and play an important role in hepatobiliary excretion. We investigated the transport function and subcellular localization of mrp6, a novel member of the mrp family, in rat liver. Transport studies in vesicles isolated from mrp6 expressing Sf9 cells identified the anionic cyclopentapeptide and endothelin receptor antagonist BQ-123 as a substrate of mrp6 (K(m) approximately 17 microM). Besides BQ-123, which is also a substrate of mrp2 (K(m) approximately 124 microM), no other common substrates were found for mrp2, mrp6, and the canalicular bile salt export pump Bsep. The cyclic peptides endothelin I and Arg(8)-vasopressin were transported by mrp2 but not by mrp6. Using a polyclonal antiserum raised against a C-terminal peptide, mrp6 was found to be localized at the lateral and, to a lesser extent, at the canalicular plasma membrane of hepatocytes. The limited overlap of the substrate specificity with the canalicular export pumps mrp2 and Bsep indicates that mrp6 does not play a major role in canalicular organic anion excretion. However, its dual localization at the lateral and canalicular plasma membrane suggests that mrp6 might fulfill a "housekeeping" transport function involved in the regulation of paracellular and/or transcellular solute movement from blood into bile.


Gene Ontology Annotations    

Biological Process

Cellular Component

Molecular Function

Objects Annotated

Genes (Rattus norvegicus)
Abcc6  (ATP binding cassette subfamily C member 6)

Additional Information