Title

Ultrastructure of human erythrocyte GLUT1

GSBS Program

Biochemistry & Molecular Pharmacology

UMMS Affiliation

Graduate School of Biomedical Sciences; Department of Biochemistry and Molecular Pharmacology

Date

6-28-2006

Document Type

Article

Medical Subject Headings

Blood Glucose; Detergents; Erythrocytes; Freeze Fracturing; Glucose Transporter Type 1; Humans; Kinetics; Light; Lipids; Micelles; Microscopy, Electron; Protein Conformation; Protein Structure, Quaternary; Scattering, Radiation

Disciplines

Life Sciences | Medicine and Health Sciences

Abstract

This study was undertaken to examine GLUT1 quaternary structure. Independent but complementary methodologies were used to investigate the influence of membrane-solubilizing detergents on GLUT1/lipid/detergent micelle hydrodynamic radii. Hydrodynamic size analysis and electron microscopy of GLUT1/lipid/detergent micelles and freeze-fracture electron microscopy of GLUT1 proteoliposomes support the hypothesis that the glucose transporter is a multimeric (probably tetrameric) complex of GLUT1 proteins. GLUT1 forms a multimeric complex in octyl glucoside that dissociates upon addition of reductant. Some detergents (e.g., CHAPS and dodecyl maltoside) promote the dissociation of GLUT1 oligomers into smaller aggregation states (dimers or monomers). These complexes do not reassemble as larger oligomers when dissociating detergents are subsequently replaced with nondissociating detergents such as octyl glucoside or cholic acid. When dissociating detergents are replaced with lipids, the resulting proteoliposomes catalyze protein-mediated sugar transport, and the subsequent addition of solubilizing, nondissociating detergents generates higher (tetrameric) GLUT1 aggregation states. These findings suggest that some detergents stabilize while others destabilize GLUT1 quaternary structure. GLUT1 does not appear to exchange rapidly between protein/lipid/detergent micelles but is able to self-associate in the plane of the lipid bilayer.

Rights and Permissions

Citation: Biochemistry. 2006 Jul 4;45(26):8096-107. Link to article on publisher's site

Related Resources

Link to article in PubMed