Electrogenic Na+-coupled sugar symporter that actively transports D-mannose or D-fructose at the plasma membrane, with a Na+ to sugar coupling ratio of 1:1. Transporter activity is driven by a transmembrane Na+ electrochemical gradient set by the Na+/K+ pump. Exclusively recognizes sugar substrates having a pyranose ring with an axial hydroxyl group on carbon 2 ( ). Has likely evolved to enable renal reabsorption of D-mannose, an important constituent of oligosaccharide chains of glycoproteins. Contributes to dietary D-fructose reabsorption from glomerular filtrate across the brush border of the kidney (, ).
Appears to have no transporter activity.
Subcellular locations: Apical cell membrane
Predominantly expressed at high levels in kidney. Very low expression is detected in testes.
Expressed in kidney.
The most abundant isoform expressed in kidney.
Expressed in kidney.
Expressed in kidney.