Opposite and redundant roles of the two Drosophila Perilipins in lipid mobilization
    作者: Junfeng Bi,Yanhui Xiang,Haiyang Chen,Zhonghua Liu,Sebastian Grönke,Ronald P. Kühnlein and Xun Huang
    刊物名称: Journal of Cell Science
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    Lipid droplets are the main lipid storage sites in cells. Lipid droplet homeostasis is regulated by the surface accessibility of lipases. Mammalian adipose triglyceride lipase (ATGL) and hormone-sensitive lipase (HSL) are two key lipases for basal and stimulated lipolysis, respectively. Perilipins, the best known lipid droplet surface proteins, can either recruit lipases or prevent the access of lipases to lipid droplets. Mammals have five Perilipins, which often exhibit redundant functions, precluding the analysis of the exact role of individual Perilipin in vivo. Drosophila has only two Perilipins, PLIN1/LSD-1 and PLIN2/LSD-2. Previous studies revealed that PLIN2 is important for protecting lipid droplets from lipolysis mediated by Brummer (BMM), the Drosophila homolog of ATGL. In this study, we report the functional analysis of PLIN1 and Drosophila HSL (dHSL). Loss-of-function and overexpression studies reveal that as opposed to PLIN2, PLIN1 likely facilitates lipid mobilization. dHSL is recruited from the cytosol to the surface of lipid droplets under starved conditions and PLIN1 is necessary for the starved induced lipid droplet localization of dHSL. Moreover, phenotypic analysis of plin1;plin2 double mutants revealed that PLIN1 and PLIN2 may have redundant functions in protecting lipid droplets from lipolysis. Therefore, the two Drosophila Perilipins have both opposite and redundant roles. Domain swapping and deletion analyses indicate that the C-terminal region of PLIN1 confers functional specificity on PLIN1. Our study highlights the complex roles of Drosophila Perilipins proteins and the evolutionarily conserved regulation of HSL translocation by Perilipins.