Fig. 5
From: The a subunit isoforms of V-ATPase are involved in glucose-dependent trafficking of insulin granules
Insulin secretion, morphology of insulin granules, and expression of insulin and its related genes in control and a2KD MIN6 cells. (A) Total insulin content in control (open bars) and a2KD#1 (closed bars) cells. (B) Insulin secretion from control (open bars) and a2KD#1 (closed bars) cells. Cells were treated with KRH buffer containing 2 or 20 mM glucose for 2 h, and then the insulin content in the recovered medium and acid ethanol extracts was determined using an ELISA kit. Insulin secretion from control cells treated with 2 mM glucose was set to 1. Data are means ± S.E. from four independent experiments. (C) Electron micrographs of control (upper panels) and a2KD#1 (lower panels) cells in HEPES-buffered Krebs buffer containing 2.2 mM glucose. Magnified images of the boxed areas are shown in the right panels. Arrows indicate typical insulin granules with a dense core. (D) Expression of insulin and insulin-related genes in control (open bars) and a2KD#1 (closed bars) cells. Total mRNA was isolated from cells in HEPES-buffered Krebs buffer containing 2.2 mM glucose. The expression levels of Ins1, Ins2, PC1/3, and PC2 were quantified by real-time RT-PCR using β-actin as an internal standard, with expression in control cells set to 1. Ins1, insulin 1; Ins2, insulin 2; PC1/3, prohormone convertase 1/3; PC2, prohormone convertase 2. Data are means ± S.E. from three independent experiments. *p < 0.05, unpaired two-tailed Student’s t-test.
