Galectin 9 is the sugar-regulated urate transporter/channel UAT.
UAT, also designated galectin 9, is a multifunctional protein that can function as a urate channel/transporter, a regulator of thymocyte-epithelial cell interactions, a tumor antigen, an eosinophil chemotactic factor, and a mediator of apoptosis. We review the evidence that UAT is a transmembrane protein that transports urate, describe our molecular model for this protein, and discuss the evidence from epitope tag and lipid bilayer studies that support this model of the transporter. The properties of recombinant UAT are compared with those of urate transport into membrane vesicles derived from proximal tubule cells in rat kidney cortex. In addition, we review channel functions predicted by our molecular model that resulted in the novel finding that the urate channel activity is regulated by sugars and adenosine. Finally, the presence and possible functions of at least 4 isoforms of UAT and a closely related gene hUAT2 are discussed.
Lipkowitz
Michael S
MS
Division of Nephrology, Department of Medicine, Mount Sinai School of Medicine, New York, New York 10029, USA. mike.lipkowitz@mssm.edu
Leal-Pinto
Edgar
E
Cohen
B Eleazar
BE
Abramson
Ruth G
RG
D000818:Animals; D050260:Carbohydrate Metabolism; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D037161:Galectins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D027361:Organic Anion Transporters / Q000235:genetics / Q000378:metabolism*; D027701:Organic Cation Transport Proteins; D014527:Uric Acid / Q000378:metabolism
D002352:Carrier Proteins; D037161:Galectins; C491242:Lgals9 protein, rat; D027361:Organic Anion Transporters; D027701:Organic Cation Transport Proteins; C491241:SLC22A12 protein, human; C103862:urate transporter; D014527:Uric Acid