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Updated: Jun 26, 2026
05:28
Demonstration of Heterologous Complexes formed by Golgi-Resident Type III Membrane Proteins using Split Luciferase Complementation Assay
Published on: September 10, 2020
GLUT8, the enigmatic intracellular hexose transporter
Stefan Schmidt1, Hans-Georg Joost, Annette Schürmann
1Department of Pharmacology, German Institute of Human Nutrition Potsdam-Rehbruecke, Arthur-Scheunert-Allee 114-116, D-14558 Nuthetal, Germany.
American Journal of Physiology. Endocrinology and Metabolism
|January 30, 2009
Summary
Glucose transporter 8 (GLUT8) functions intracellularly, not at the plasma membrane. GLUT8 knockout mice show mild brain, heart, and sperm cell alterations.
Area of Science:
- Molecular Biology
- Cell Biology
- Physiology
Background:
- GLUT8 is a class III sugar transporter primarily found in the testis and brain.
- Structural analysis suggests unique extracellular loops and an N-glycosylation site.
- GLUT8 possesses an N-terminal targeting motif for endosomes and lysosomes.
Purpose of the Study:
- To investigate the cellular localization and function of GLUT8.
- To characterize the physiological impact of GLUT8 deficiency using knockout mice.
Main Methods:
- In vitro translation and glycosylation assays.
- Heterologous expression systems to study glucose transport kinetics and inhibition.
- Immunofluorescence and subcellular localization studies in various cell systems.
- Analysis of Slc2a8 knockout mice phenotypes.
Main Results:
- GLUT8 exhibits glucose transport activity inhibited by fructose and galactose.
- GLUT8 localizes to endosomes, lysosomes, and endoplasmic reticulum membranes, with no plasma membrane translocation observed.
- Slc2a8 knockout mice display viable development with mild neurological, cardiac, and sperm cell abnormalities.
Conclusions:
- GLUT8 likely mediates sugar transport across intracellular membranes.
- The precise relationship between GLUT8's molecular function, localization, and observed knockout phenotypes requires further investigation.
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