transient SGLT1 currents recorded on the SURFE2R N1

SGLT1 - Sodium/Glucose Cotransporter 1 - SLC5A1

Targets and Family: SGLT1 belongs to the Solute:Sodium Symporter Family (SSSF, TCDB: 2.A.21). Since it is a human transporter, it’s also classified as an SLC transporter: SGLT1 equals to SLC5a1 and belongs to the sodium/glucose cotransport family (SLC5).

Function: Absorption of D-glucose in the small intestine using the sodium transmembrane gradient, which is established by the Na+/K+ ATPase. Na+/sugar symport occurs with 2:1 stoichiometry. SGLT1 is known as a high-affinity / low-capacity transporter, having an affinity for its main substrate D-glucose of 0.5 mM and a transport rate of 20 molecules per second.

Organism and Localisation: SGLT1 is a mammalian transporter, localized within the plasma membrane of the small intestine, specifically in the lower segments. Here the high affinity allows for absorption of D-glucose, which was not absorbed by SGLT2. Defects in SGLT1 function can lead to congenital glucose/galactose malabsorption (GGM), an autosomal recessive disorder.

Substrates and Inhibitors: D-glucose is the physiological most relevant substrate. Methyl-D-glucose is often used for experiments on SGLT1, due to the fact that it is not metabolized, but exhibits similar transport properties as D-glucose. Other substrates are galactose; some transport activity was also observed for D-xylose, 2-Desoxy-D-glucose and 3-O-Methyl-D-glucose. Sugar transport is coupled to Na+ translocation, but Na+ can be replaced by Li+ and H+. Well-characterized inhibitors are Phlorizin, which has a very high affinity in the nM range for the extracellular site of SGLT1, but very week affinity for the intracellular site. SGLT1 is also inhibited by Phloretin with an IC50 of ~ 100 µM.

Related Transporters: SGLT2 has a different tissue distribution than SGLT1, and is expressed predominantly in the upper segments of the small intestine. It has a higher transport capacity, but lower affinity for D-glucose and a 1:1 Na+/D-glucose transport stoichiometry. Other functionally related transporters belong to the GLUT family, which are human D-glucose uniporters or the SWEET family, which contain sugar transporters first found in plants. Highly relevant is also the prototypical and famous bacterial proton-coupled lactose transporter LacY from E.coli.

Data and Applications

SGLT1 - Sugar transport and binding

SGLT1 Figure 1   pss vs ss

Icon N1   SURFE2R N1 data and applications:

Short Description: Na+/sugar translocation is detected using a sugar concentration jump in presence of sodium. In absence of sodium, we found a pre steady-state signal, representing sugar binding. Under these conditions, no transport is observed. 
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SGLT1 - EC50 for D-glucose transport

SGLT1 Figure 2   EC50 glucose

Icon N1   SURFE2R N1 data and applications:

Short Description: Na+/sugar translocation is detected using a sugar concentration jump in presence of sodium. Here we determined the KM for glucose transport by SGLT1. 
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SGLT1 - Current Traces after Application of alpha-MDG


Icon N1   SURFE2R N1 data and applications:

Current traces after application of 10 mM and 50 mM alpha-MDG.



2020 - A novel approach to detect electrogenic transporter activity in intact cells applied to investigate iPSC derived cardiomyocytes and neurons

 Icon N1   SURFE²R N1 and   Icon 96SE   SURFE²R 96SE poster, 64th Annual Meeting of the Biophysical Society   logo pdf   (1.6 MB)

2017 - An emerging technique for the characterization of transport proteins: SSM-based electrophysiology

Icon N1   SURFE²R N1 and    Icon 96SE   SURFE²R SE96 poster, 19th IUPAB / 11th EBSA congress 2017  logo pdf   (3.3 MB)

2015 - Studying Electrogenic Transporters of the SLC Family in a Parallel Way Utilizing Solid Supported Membrane Technology

Icon 96SE   SURFE²R N96 poster (a predecessor model of the SURFE²R 96SE) Biophysics 2015   logo pdf   (0.8 MB)

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