Organic anion transporters (OATs) mediate the absorption, distribution, and excretion of a diverse array of environmental toxins, and clinically important drugs, including anti-HIV therapeutics, anti-tumor drugs, antibiotics, anti-hypertensives, and anti-inflammatories. OATs are mainly expressed in the kidney, liver, brain and placenta. OAT dysfunction in these organs significantly contributes to the renal, hepatic, neurological and fetal toxicity and disease. Our long-term goal is to define the molecular mechanisms underlying drug disposition through the OAT pathway. During the previous grant period, significant progress and productivity have been achieved, and the new findings from this period led to the establishment of a fine-tuned research plan and strategy in this competing renewal. We propose to test the novel hypothesis that Nedd4-2, an ubiquitin ligase, serves as a central convergence point/switch for protein kinase-regulated OAT1 activity, and therefore for transducing diverse physiological stimuli to OAT1-mediated drug transport.
Three Specific Aims are outlined.
In Specific Aim I, we will map protein kinase-specific phosphorylation sites on Nedd4-2, and examine whether phosphorylation of Nedd4-2 is the mechanism by which diverse protein kinases regulate OAT1 transport activity.
In Specific Aim II, we will identify the specific domains/amino acid residues in OAT1 and Nedd4-2, critical for the interaction between these two proteins.
In Specific Aim III, we will evaluate the physiological role of Nedd4-2 in OAT1-mediated drug transport. Combined approaches of biochemistry and molecular biology will be employed for the proposed studies in cultured cells, and in kidney slices from normal and Nedd4-2 knockout mice. Understanding the role of dynamic phosphorylation of Nedd4-2 in the regulation of OATs, a novel focus in drug transport field, will have significant impact on the future design of strategies aimed at maximizing therapeutic efficacy and minimizing toxicity, and will permit insight into the molecular, cellular, and clinical bases of renal, hepatic, neurologica and fetal toxicity and disease.

Public Health Relevance

(the same as the original) The organic anion transporter (OAT) family mediates the absorption, distribution, and excretion of a diverse array of environmental toxins, and clinically important drugs. Therefore, understanding the regulation of OATs will have significant impact on the future design of therapeutic strategies. 3

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
2R01GM079123-05
Application #
8691564
Study Section
Xenobiotic and Nutrient Disposition and Action Study Section (XNDA)
Program Officer
Okita, Richard T
Project Start
2006-12-01
Project End
2017-12-31
Budget Start
2014-04-01
Budget End
2014-12-31
Support Year
5
Fiscal Year
2014
Total Cost
$264,414
Indirect Cost
$84,414
Name
Rutgers University
Department
Pharmacology
Type
Schools of Pharmacy
DUNS #
001912864
City
New Brunswick
State
NJ
Country
United States
Zip Code
08901
Li, Shanshan; Zhang, Qiang; You, Guofeng (2013) Three ubiquitination sites of organic anion transporter-1 synergistically mediate protein kinase C-dependent endocytosis of the transporter. Mol Pharmacol 84:139-46
Zhang, Qiang; Li, Shanshan; Patterson, Cam et al. (2013) Lysine 48-linked polyubiquitination of organic anion transporter-1 is essential for its protein kinase C-regulated endocytosis. Mol Pharmacol 83:217-24
Duan, Peng; Wu, Jinwei; You, Guofeng (2011) Mutational analysis of the role of GXXXG motif in the function of human organic anion transporter 1 (hOAT1). Int J Biochem Mol Biol 2:1-7
Duan, Peng; Li, Shanshan; You, Guofeng (2011) Transmembrane peptide as potent inhibitor of oligomerization and function of human organic anion transporter 1. Mol Pharmacol 79:569-74
Zhang, Qiang; Wu, Jinwei; Pan, Zui et al. (2011) The Role of Dileucine in the Expression and Function of Human Organic Anion Transporter 1 (hOAT1). Int J Biochem Mol Biol 2:31-38
Li, Shanshan; Duan, Peng; You, Guofeng (2010) Regulation of human organic anion transporter 3 by peptide hormone bradykinin. J Pharmacol Exp Ther 333:970-5
Duan, Peng; You, Guofeng (2010) Short-term regulation of organic anion transporters. Pharmacol Ther 125:55-61
Hong, Mei; Li, Shanshan; Zhou, Fanfan et al. (2010) Putative transmembrane domain 12 of the human organic anion transporter hOAT1 determines transporter stability and maturation efficiency. J Pharmacol Exp Ther 332:650-8
Zhang, Qiang; Pan, Zui; You, Guofeng (2010) Regulation of human organic anion transporter 4 by protein kinase C and NHERF-1: altering the endocytosis of the transporter. Pharm Res 27:589-96
Duan, Peng; Li, Shanshan; You, Guofeng (2010) Angiotensin II inhibits activity of human organic anion transporter 3 through activation of protein kinase Calpha: accelerating endocytosis of the transporter. Eur J Pharmacol 627:49-55

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