Functional characterisation of human SGLT-5 as a novel kidney-specific sodium-dependent sugar transporter

FEBS Lett. 2012 Feb 3;586(3):248-53. doi: 10.1016/j.febslet.2011.12.027. Epub 2011 Dec 30.

Abstract

Sodium glucose cotransporters (SGLT) actively catalyse carbohydrate transport across cellular membranes. Six of the 12 known SGLT family members have the capacity to bind and/or transport monosaccharides (SGLT-1 to 6); of these, all but SGLT-5 have been characterised. Here we demonstrate that human SGLT-5 is exclusively expressed in the kidney. Four splice variants were detected and the most abundant SGLT-5-mRNA was functionally characterised. SGLT-5 mediates sodium-dependent [(14)C]-α-methyl-D-glucose (AMG) transport that can be inhibited by mannose, fructose, glucose, and galactose. Uptake studies using demonstrated high capacity transport for mannose and fructose and, to a lesser extent, glucose, AMG, and galactose. SGLT-5 mediated mannose, fructose and AMG transport was weakly (μM potency) inhibited by SGLT-2 inhibitors. In summary, we have characterised SGLT-5 as a kidney mannose transporter. Further studies are warranted to explore the physiological role of SGLT-5.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Absorption / drug effects
  • Biological Transport / drug effects
  • Cloning, Molecular
  • Gene Expression Regulation / drug effects
  • Glucose / metabolism
  • HEK293 Cells
  • Humans
  • Kidney / metabolism*
  • Organ Specificity
  • Phlorhizin / pharmacology
  • Protein Isoforms / antagonists & inhibitors
  • Protein Isoforms / chemistry
  • Protein Isoforms / genetics
  • Protein Isoforms / metabolism
  • Protein Stability
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Sodium-Glucose Transporter 1 / antagonists & inhibitors
  • Sodium-Glucose Transporter 1 / chemistry
  • Sodium-Glucose Transporter 1 / genetics
  • Sodium-Glucose Transporter 1 / metabolism*

Substances

  • Protein Isoforms
  • RNA, Messenger
  • Sodium-Glucose Transporter 1
  • Phlorhizin
  • Glucose