UMMS Affiliation

Department of Cell Biology; Department of Physiology; Program in Molecular Medicine

Publication Date

2-13-2001

Document Type

Article

Subjects

3T3 Cells; Adipocytes; Animals; Cytoskeleton; Diagnostic Imaging; Exocytosis; Glucose Transporter Type 4; Green Fluorescent Proteins; Half-Life; Insulin; Luminescent Proteins; Mice; Microscopy, Confocal; Monosaccharide Transport Proteins; *Muscle Proteins; Protein Transport; Rats; Recombinant Fusion Proteins; Transport Vesicles

Disciplines

Life Sciences | Medicine and Health Sciences

Abstract

A novel imaging technology, high-speed microscopy, has been used to visualize the process of GLUT4 translocation in response to insulin in single 3T3-L1 adipocytes. A key advantage of this technology is that it requires extremely low light exposure times, allowing the quasi-continuous capture of information over 20-30 min without photobleaching or photodamage. The half-time for the accumulation of GLUT4-eGFP (enhanced green fluorescent protein) at the plasma membrane in a single cell was found to be of 5-7 min at 37 degrees C. This half-time is substantially longer than that of exocytic vesicle fusion in neuroendocrine cells, suggesting that additional regulatory mechanisms are involved in the stimulation of GLUT4 translocation by insulin. Analysis of four-dimensional images (3-D over time) revealed that, in response to insulin, GLUT4-eGFP-enriched vesicles rapidly travel from the juxtanuclear region to the plasma membrane. In nontransfected adipocytes, impairment of microtubule and actin filament function inhibited insulin-stimulated glucose transport by 70 and 50%, respectively. When both filament systems were impaired insulin-stimulated glucose transport was completely inhibited. Taken together, the data suggest that the regulation of long-range motility of GLUT4-containing vesicles through the interaction with microtubule- and actin-based cytoskeletal networks plays an important role in the overall effect of insulin on GLUT4 translocation.

Rights and Permissions

Citation: Mol Biol Cell. 2001 Jan;12(1):129-41.

Related Resources

Link to Article in PubMed

Journal/Book/Conference Title

Molecular biology of the cell

PubMed ID

11160828

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