GSBS Student Publications

Title

Glucose transporter oligomeric structure determines transporter function. Reversible redox-dependent interconversions of tetrameric and dimeric GLUT1

Student Author(s)

Daniel N. Hebert

GSBS Program

Biochemistry & Molecular Pharmacology

UMMS Affiliation

Department of Biochemistry and Molecular Pharmacology; Program in Molecular Medicine

Date

11-25-1992

Document Type

Article

Medical Subject Headings

Binding Sites; Chromatography, Gel; Cytochalasin B; Enzyme-Linked Immunosorbent Assay; Erythrocyte Membrane; Erythrocytes; Glucose; Glutathione; Glutathione Disulfide; Humans; Immunoglobulin G; Kinetics; Macromolecular Substances; Models, Structural; Molecular Weight; Monosaccharide Transport Proteins; purification; Oxidation-Reduction; Protein Binding; Protein Denaturation

Disciplines

Biochemistry, Biophysics, and Structural Biology | Life Sciences | Medicine and Health Sciences

Abstract

This study investigates the relationship between human erythrocyte glucose transport protein (GLUT1) oligomeric structure and glucose transporter function. Oligomeric structure was analyzed by hydrodynamic studies of cholate-solubilized GLUT1, by chemical cross-linking studies of membrane-resident GLUT1 and by using conformation-specific antibodies. Transporter function (substrate binding) was analyzed by equilibrium cytochalasin B and D-glucose binding measurements. Erythrocyte-resident glucose transporter is a GLUT1 homotetramer, binds 1 mol of cytochalasin B/2 mol of GLUT1, and presents at least two binding sites to D-glucose. Native structure and function appear to be stabilized by intramolecular disulfide bonds and are preserved during GLUT1 purification by the omission of reductant. Native structure is independent of in vitro and in vivo membrane GLUT1 density but is transformed to dimeric GLUT1 by alkaline reduction. Dimeric GLUT1 binds 1 mol of cytochalasin B/mol of GLUT1, presents a single population of binding sites to D-glucose, and is obtained upon GLUT1 purification in the presence of reductant. Native structure and function are restored by treatment of dimeric GLUT1 with glutathione-disulfide (K0.5 glutathione disulfide = 29 microM). We propose that native structure is established prior to transporter translocation to the plasma membrane and that intrasubunit disulfide bonds promote cooperative subunit interactions that stabilize transporter structure and function.

Rights and Permissions

Citation: J Biol Chem. 1992 Nov 25;267(33):23829-38.

Related Resources

Link to article in PubMed

Journal Title

The Journal of biological chemistry

PubMed ID

1429721