Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093.
Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093
Proc Natl Acad Sci U S A. 2018 Jul 17;115(29):7485-7490. doi: 10.1073/pnas.1804266115. Epub 2018 Jul 2.
Mammalian cells synthesize thousands of distinct lipids, yet the function of many of these lipid species is unknown. Ceramides, a class of sphingolipid, are implicated in several cell-signaling pathways but poor cell permeability and lack of selectivity in endogenous synthesis pathways have hampered direct study of their effects. Here we report a strategy that overcomes the inherent biological limitations of ceramide delivery by chemoselectively ligating lipid precursors in vivo to yield natural ceramides in a traceless manner. Using this method, we uncovered the apoptotic effects of several ceramide species and observed differences in their apoptotic activity based on acyl-chain saturation. Additionally, we demonstrate spatiotemporally controlled ceramide synthesis in live cells through photoinitiated lipid ligation. Our in situ lipid ligation approach addresses the long-standing problem of lipid-specific delivery and enables the direct study of unique ceramide species in live cells.
哺乳动物细胞合成数千种不同的脂质，但其中许多脂质的功能尚不清楚。神经酰胺是一类鞘脂，参与了几种细胞信号通路，但由于内源性合成途径的细胞通透性差和选择性差，限制了对其作用的直接研究。在这里，我们报告了一种策略，通过在体内选择性地连接脂质前体来克服神经酰胺传递的固有生物学限制，以无痕迹的方式产生天然神经酰胺。使用这种方法，我们发现了几种神经酰胺的凋亡作用，并观察到它们根据酰基链饱和度的不同，其凋亡活性也不同。此外，我们通过光引发的脂质连接在活细胞中证明了时空控制的神经酰胺合成。我们的原位脂质连接方法解决了脂质特异性传递的长期问题，并使我们能够直接在活细胞中研究独特的神经酰胺。
