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Updated: May 9, 2026
13:16
Characterization of Membrane Transporters by Heterologous Expression in E. coli and Production of Membrane Vesicles
Published on: December 31, 2019
Type 1 sodium-dependent phosphate transporter acts as a membrane potential-driven urate exporter
Takaaki Miyaji1, Tatsuya Kawasaki, Natsuko Togawa
1Advanced Science Research Center, Okayama University, Okayama 700-8530, Japan. tmiyaji@pharm.okayama-u.ac.jp
Current Molecular Pharmacology
|July 24, 2013
Summary
The SLC17A1 (NPT1) protein transports organic anions like urate. A specific mutation linked to gout significantly reduced urate transport, identifying NPT1 as a key renal urate exporter.
Area of Science:
- Biochemistry
- Molecular Biology
- Physiology
Background:
- SLC17A1 protein (NPT1) is a phosphate transporter with suggested but uncharacterized roles as a renal anion exporter.
- Previous studies indicated NPT1 mediates Na+/inorganic phosphate (Pi) co-transport.
Purpose of the Study:
- To characterize the transport properties of the SLC17A1 (NPT1) protein.
- To investigate the role of NPT1 in renal urate excretion and its potential link to gout.
Main Methods:
- Purified NPT1 protein reconstituted into proteoliposomes.
- Assessed transport of organic anions (urate, PAH, aspirin) driven by membrane potential (Δψ) and chloride dependence.
- Analyzed the effect of a Thr269Ile SNP mutation on urate transport activity.
Main Results:
- Proteoliposomes with purified NPT1 transported urate, p-aminohippuric acid (PAH), and aspirin in a Δψ-driven and Cl(-)-dependent manner.
- The Thr269Ile NPT1 mutation, associated with gout risk, showed 32% reduced urate transport compared to wild type.
- These findings identify NPT1 as a significant transporter of renal urate.
Conclusions:
- NPT1 functions as a polyspecific organic anion transporter, particularly for urate.
- NPT1 is identified as the long-sought transporter responsible for renal urate excretion.
- The Thr269Ile mutation's impact on urate transport highlights NPT1's role in urate homeostasis and gout pathophysiology.
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