JCI - Insulin-induced cortical actin remodeling promotes GLUT4 insertion at muscle cell membrane ruffles

Insulin-induced cortical actin remodeling promotes GLUT4 insertion at muscle cell membrane ruffles

Peter Tong, Zayna A. Khayat, Carol Huang, Nish Patel, Atsunori Ueyama, Amira Klip

J Clin Invest. 2001; 108(3):371–381 doi:10.1172/JCI12348

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Figure 4

Immunogold-labeled cell-surface GLUT4 appears in membrane ruffles in response to insulin. (a) Serum-deprived L6 GLUT4myc myotubes were treated without and with 100 nM insulin at 37°C for 15 minutes and then labeled with anti-myc antibody followed by 30 nm gold-conjugated goat anti-mouse antibody to label cell-surface GLUT4myc. Specimens were prepared for scanning electron microscopy as described in Methods. Shown is the topography of a section of the surface of an insulin-stimulated myotube with the backscattered electrons from the gold particles seen as white dots (encircled). Scale bar = 1 μm. (b) Quantitation of gold particles in unstimulated cells and in ruffled or nonruffled regions of insulin-stimulated cells’ surfaces. The number of gold particles was quantitated by applying a 3 × 3 cm grid to the computerized images of control and insulin-stimulated cells from four independent experiments and by counting the number of white dots in five randomly chosen squares within each grid. *P < 0.001 relative to control.