Validating an artificial organelle: Studies of lipid droplet-specific proteins on adiposome platform

• Published in: iScience Vol. 24; no. 8; p. 102834
• Main Authors: Ma, Xuejing, Zhi, Zelun, Zhang, Shuyan, Zhou, Chang, Mechler, Adam, Liu, Pingsheng
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 20.08.2021; Elsevier
• Subjects: Biophysics; Cell biology; Functional aspects of cell biology; Cell biology; Functional aspects of cell biology; Biophysics
• ISSN: 2589-0042; 2589-0042
• DOI: 10.1016/j.isci.2021.102834

New strategies are urgently needed to characterize the functions of the lipid droplet (LD). Here, adiposome, an artificial LD mimetic platform, was validated by comparative in vitro bioassays. Scatchard analysis found that the binding of perilipin 2 (PLIN2) to the adiposome surface was saturable. Phosphatidylinositol (PtdIns) was found to inhibit PLIN2 binding while it did not impede perilipin 3 (PLIN3). Structural analysis combined with mutagenesis revealed that the 73rd glutamic acid of PLIN2 is significant for the effect of PtdIns on the PLIN2 binding. Furthermore, adiposome was also found to be an ideal platform for in situ enzymatic activity measurement of adipose triglyceride lipase (ATGL). The significant serine mutants of ATGL were found to cause the loss of lipase activity. Our study demonstrates the adiposome as a powerful, manipulatable model system that mimics the function of LD for binding and enzymatic activity studies of LD proteins in vitro. [Display omitted] •An artificial organelle was validated for the targeting and regulation of LD proteins•Binding affinity analysis of PLIN2 targeting on artificial LD was performed•PtdIns and the 73rd glutamic acid in PLIN2 affect the targeting of PLIN2 to LD•In situ enzymatic activity of ATGL was demonstrated and measured via artificial LD Cell biology; Functional aspects of cell biology; Biophysics