1. Regulation of lipid droplet formation by PI3-kinase activity.
Regulation of lipid droplet formation by PI3-kinase activity. The localisation of EGFP–Grp1-PH was examined by spinning disk confocal recording of cells stably expressing the fusion protein. (A) Translocation of EGFP–Grp1-PH to the plasma membrane was observed following stimulation with oleate for 1 min (arrows). (B) No GPR1–EGFP translocation to the plasma membrane was observed following stimulation with the short-chain capric acid. (C) Huh-7 cells were preincubated with the PI3-kinase inhibitor LY (10 µM) prior to stimulation with 100 µM oleate (OA) for 15 min or 180 min. Open bars, LY treated cells; closed bars, untreated cells. Data are expressed as the mean±s.e.m., normalised to the number of lipid droplets in fatty-acid-starved cells (starvation). The P-values are: 15 min, P = 0.005; 180 min, P<0.001 (Student's t-test). (D) The ratio of PtdIns(3,4,5)P3∶PtdInsP2 in Huh-7 cells after stimulation with 100 µM oleate. The data were normalised to results from fatty-acid-starved cells (Starv) and are expressed as the mean±s.d. The P-values are: 15 min, P = 0.2; 180 min, P = 0.09 (Mann-Whitney U test). Closed bars, control Huh-7 cells; open bars, FFAR4-knockdown cells (see Fig. 8).
Arndt Rohwedder et al. J Cell Sci 2014;127:
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