Organic anion transporters in the kidney proximal tubule play an essential role in eliminating a wide range of organic anions including endogenous compounds, xenobiotics, and their metabolites, thereby preventing their potentially toxic effects within the body. We have previously cloned a cDNA encoding an organic anion transporter from mouse kidney (mOAT) (Lopez-Nieto, C. E., You, G., Bush, K. T., Barros, E. J. G., Beier, D. R., and Nigam, S. K. (1997)J. Biol. Chem. 272, 6471–6478; Kuze, K., Graves, P., Leahy, A., Wilson, P., Stuhlmann, H., and You, G. (1999) J. Biol. Chem. 274, 1519–1524). In the present study, we assessed the potential for regulation of this transporter by heterologous expression of mOAT in the pig proximal tubule-like cell line, LLC-PK1. We report here that both protein phosphatase (PP1/PP2A) inhibitor, okadaic acid, and protein kinase C (PKC) activators down-regulate mOAT-mediated transport of para-aminohippuric acid (PAH), a prototypic organic anion, in a time- and concentrationdependent manner. However their mechanisms of action for this down-regulation are distinct. Okadaic acid modulated PAH transport, at least in part, through phosphorylation/dephosphorylation of mOAT; phosphoamino acid analysis indicated this phosphorylation occurs on serine. In contrast, PKC activation induced a decrease in the maximum transport velocity (V max) of PAH transport without direct phosphorylation of the transporter protein. Together these results provide the first demonstration that regulation of organic anion transport by mOAT is likely to be tightly controlled directly and indirectly by phosphatase PP1/PP2A and PKC. Our results also suggest that kinases other than PKC are involved in this process.
Regulation of mOAT-mediated Organic Anion Transport by Okadaic Acid and Protein Kinase C in LLC-PK1 Cells*
G. You,K. Kuze,R. Kohanski,K. Amsler,S. Henderson
Published 2000 in Journal of Biological Chemistry
ABSTRACT
PUBLICATION RECORD
- Publication year
2000
- Venue
Journal of Biological Chemistry
- Publication date
2000-04-07
- Fields of study
Biology, Medicine, Chemistry
- Identifiers
- External record
- Source metadata
Semantic Scholar, PubMed
CITATION MAP
EXTRACTION MAP
CLAIMS
- No claims are published for this paper.
CONCEPTS
- No concepts are published for this paper.
REFERENCES
Showing 1-32 of 32 references · Page 1 of 1
CITED BY
Showing 1-97 of 97 citing papers · Page 1 of 1