Quantitative Analysis of Lipid Droplet Fusion: Inefficient Steady State Fusion but Rapid Stimulation by Chemical Fusogens

摘要: Lipid droplets (LDs) are dynamic cytoplasmic organelles containing neutral lipids and bounded by a phospholipid monolayer. Previous studies have suggested that LDs can undergo constitutive homotypic fusion, process linked to the inhibitory effects of fatty acids on glucose transporter trafficking. Using strict quantitative criteria for LD fusion together with refined light microscopic methods real-time analysis, we now show in diverse cell types low fusogenic activity under normal growth conditions. To investigate possible modulation screened agents trigger fusion. A number pharmacological caused lipid variety types. This provided novel system study rapid regulated between monolayers. involved an initial step which two adjacent membranes became continuous (<10 s), followed slower merging (100 s) cores produce single spherical LD. These events were accompanied changes surface organization. Measurements undergoing showed fused maintained their volume, corresponding decrease area suggesting removal membrane from provides estimates level cells questions role vivo. In addition, it highlights extent restructuring occurs when is triggered