FIGURE 7.

hGH secretion defects in Munc18-1 knockdown PC12-KD43 cells are rescued upon reintroduction of Munc18-1 (WT and double mutant) by transfection. A, Munc18-1 knockdown PC12 KD43 cells were co-transfected with NPY-Venus and hGH and immunostained with anti-hGH (red) and visualized by confocal microscopy. NPY-Venus (yellow) co-localizes with hGH in secretory vesicles. Scale bar, 10 μm. B, Munc18-1 knockdown PC12-KD43 cells transiently transfected with hGH and control plasmid (pCMV5), Munc18-1-WT, or Munc18-1-F115E/E132A were incubated for 20 min in the absence or presence of high K⁺ to stimulate exocytosis. hGH release is expressed as the percentage of hGH released in unstimulated conditions. Data are given as the mean ± S.E. (n = 3) and are representative of results obtained in three independent experiments. n.s., not significant (Student's t test; n = 3).