Human organic anion transporter 3 (hOAT3) can operate as an exchanger and mediate secretory urate flux.

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Bakhiya A, Bahn A, Burckhardt G, Wolff N

Human organic anion transporter 3 (hOAT3) can operate as an exchanger and mediate secretory urate flux.

Cell Physiol Biochem. 2003;13(5):249-56.

PubMed ID

14586168 [ View in PubMed

]

Abstract

BACKGROUND/AIMS: Renal secretion of organic anions is critically dependent on their basolateral uptake against the electrochemical gradient. Due to their localization, two transporters are likely involved, namely OAT1 and OAT3. While OAT1 as an exchanger clearly operates in the secretory direction, OAT3 in its previously supposed mode as a uniporter should move anionic substrates from cell to blood. It would thus dissipate gradients established by OAT1 of common OAT1/OAT3 substrates. In the present study we therefore reinvestigated the driving forces of human OAT3. METHODS: The human OAT3 obtained Xenopus laevis oocyte expression system, hOAT3-mediated transport of estrone sulfate (ES) and dicarboxylates was assayed for cis-inhibition and/or trans-stimulation in both the uptake and efflux direction. RESULTS: hOAT3-mediated efflux of glutarate (GA), can be significantly trans-stimulated by a variety of ions with high cis-inhibitory potency, including GA (282%), alpha-ketoglutarate (476%), p-aminohippurate (179%), and, most notably, urate (167%). Urate cis-inhibited ES uptake with an IC(50) close to normal serum urate concentrations. CONCLUSION: These data indicate that OAT3 does not represent a uniporter but operates as an organic ion%dicarboxylate exchanger similar to OAT1, and may mediate renal urate secretion.

DrugBank Data that Cites this Article

Drug Transporters

Drug	Transporter	Kind	Organism	Pharmacological Action	Actions
Aminohippuric acid	Solute carrier family 22 member 8	Protein	Humans	Unknown	Substrate Inhibitor	Details
Cimetidine	Solute carrier family 22 member 8	Protein	Humans	Unknown	Substrate Inhibitor	Details
Glutaric Acid	Solute carrier family 22 member 8	Protein	Humans	Unknown	Substrate Inhibitor	Details

Polypeptides

Name	UniProt ID
Solute carrier family 22 member 8	Q8TCC7	Details

Binding Properties

Drug	Target	Property	Measurement	pH	Temperature (°C)
Uric acid	Solute carrier family 22 member 8	Ki (nM)	275000	N/A	N/A	Details