Figure 6.

GIV signaling promotes insulin granule exocytosis via F-Actin remodeling.A–D, electron micrographs of β cells from GIV knockdown islets with 2.8 mM low-glucose- or 16.7 mM high-glucose-containing Krebs–Ringer bicarbonate buffer incubation. Insulin granules whose centers were located within 200 nm of the plasma membrane were categorized as docked granules and were indicated by red arrowheads. The scale bar represents 1 μm. E, the number of docked granules was calculated from 18 individual β cells by Student’s t test. ∗p < 0.05; n.s. means not significant. F–I, shRNA-treated mouse pancreatic β cells were incubated with 2.8 mM glucose and 16.7 mM glucose for 30 min, then cells were fixed and stained with phalloidin. The scale bar represents 20 μm. J, F-actin patterns in MIN6 cells were quantified as the fluorescent intensity of phalloidin by Student’s t test (n = 17). ∗∗∗p < 0.001.