Insulin Induced Changes
Muscle cells (C2C12) were infected with a fusion glucose transporter 4 green fluorescent protein (GLUT4-GFP). This protein allows the visualization of GLUT4 by imaging the GFP under fluorescent time-lapse microscopy. Frames are compiled to produce time-lapse images of cellular changes with no treatment or treatment with insulin. Untreated and vehicle treatment showed no net effect on cell behavior. Insulin produced a decrease in GLUT4-GFP around the cell nucleus and a parallel increase of movement at the membrane. Specifically, cellular filopodia (spikes) projections (shown circled) were found rapidly appearing around the cell with insulin treatment (4mM). The increase in membrane and GLUT4-GFP activity was directly associated with an increase in glucose uptake by insulin.