|
|
||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Articles in PresS, published online ahead of print October 3, 2002
Am J Physiol Regu Physiol, 10.1152/ajpregu.00392.2002
Submitted on June 28, 2002
Accepted on September 25, 2002
1 Liver Center, Yale University School of Medicine, New Haven, CT, USA
2 Department of Environmental Medicine, University of Rochester, School of Medicine, Rochester, NY, USA; Mount Desert Island Biological Laboratory, Salsbury Cove, ME, USA
3 Liver Center, Yale University School of Medicine, New Haven, CT, USA; Mount Desert Island Biological Laboratory, Salsbury Cove, ME, USA
* To whom correspondence should be addressed. E-mail: james.boyer{at}yale.edu.
Multidrug resistance protein 2 (Mrp2, symbol Abcc2) in liver plays a significant role in the biliary excretion of organic anionic conjugates. Mutations in human MRP2 result in defects in excretion of conjugated bilirubin and other cholephiles known as the Dubin-Johnson syndrome. Previous studies indicate that transporters with Mrp2 like functions are present in ancient vertebrates. We have now characterized an Mrp2 orthologue at the molecular level from the liver of the small skate, Raja erinacea, a marine vertebrate that evolved about 200 million years ago. The full-length sMrp2 cDNA is 6 kb, and encodes for a 1564 amino acid peptide with 56% identity to human MRP2. Northern-blot analysis demonstrated that sMrp2 is abundantly expressed in skate liver, intestine, and kidney. Immunoblots reveal a 180 kD protein in skate liver. Immunofluorescence studies locate sMrp2 to the apical membrane of hepatocytes, renal tubules and intestine. A PDZ-interacting motif is also found at its C-terminus. Further sequence analysis indicates that transmembrane domains 1, 9, 11, 16, 17 are the most highly conserved transmembrane domains between sMrp2 and mammalian MRP2/Mrp2s. This analysis indicates that Mrp2 orthologues evolved early in vertebrate evolution and that conserved domains may be important determinants of Mrp2 substrate specificity.
This article has been cited by other articles:
![]() |
C. H. Baehr, G. Fricker, and D. S. Miller Fluorescein-methotrexate transport in dogfish shark (Squalus acanthias) choroid plexus Am J Physiol Regulatory Integrative Comp Physiol, August 1, 2006; 291(2): R464 - R472. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. P. J. O. Elferink, R. Ottenhoff, G. Fricker, D. J. Seward, N. Ballatori, and J. Boyer Lack of biliary lipid excretion in the little skate, Raja erinacea, indicates the absence of functional Mdr2, Abcg5, and Abcg8 transporters Am J Physiol Gastrointest Liver Physiol, May 1, 2004; 286(5): G762 - G768. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |