Documenting GLUT4 exocytosis and endocytosis in muscle cell monolayers.
The elevated blood glucose following a meal is cleared by insulin-stimulated glucose entry into muscle and fat cells. The hormone increases the amount of the glucose transporter GLUT4 at the plasma membrane in these tissues at the expense of preformed intracellular pools. In addition, muscle contraction also increases glucose uptake via a gain in GLUT4 at the plasma membrane. Regulation of GLUT4 levels at the cell surface could arise from alterations in the rate of its exocytosis, endocytosis, or both. Hence, methods that can independently measure these traffic parameters for GLUT4 are essential to understanding the mechanism of regulation of membrane traffic of the transporter. Here, we describe cell population-based assays to measure the steady-state levels of GLUT4 at the cell surface, as well as to separately measure the rates of GLUT4 endocytosis and endocytosis.
Program in Cell Biology, The Hospital for Sick Children, Ontario, Canada.
Shuhei
S
Ishikura
Costin N
CN
Antonescu
Amira
A
Klip
D000818:Animals; D001681:Biological Assay / Q000379:methods*; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D004705:Endocytosis; D005089:Exocytosis; D051275:Glucose Transporter Type 4 / Q000378:metabolism*; D006801:Humans; D051379:Mice; D032342:Muscle Cells / Q000166:cytology* / Q000378:metabolism*
D051275:Glucose Transporter Type 4