Department of Cell Biology and Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, United States of America.
Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, United States of America.
Biochim Biophys Acta Mol Cell Biol Lipids. 2020 Jan;1865(1):158499. doi: 10.1016/j.bbalip.2019.07.008. Epub 2019 Jul 25.
Lipid droplets (LDs) are ubiquitous organelles that store metabolic energy in the form of neutral lipids (typically triacylglycerols and steryl esters). Beyond being inert energy storage compartments, LDs are dynamic organelles that participate in numerous essential metabolic functions. Cells generate LDs de novo from distinct sub-regions at the endoplasmic reticulum (ER), but what determines sites of LD formation remains a key unanswered question. Here, we review the factors that determine LD formation at the ER, and discuss how they work together to spatially and temporally coordinate LD biogenesis. These factors include lipid synthesis enzymes, assembly proteins, and membrane structural requirements. LDs also make contact with other organelles, and these inter-organelle contacts contribute to defining sites of LD production. Finally, we highlight emerging non-canonical roles for LDs in maintaining cellular homeostasis during stress.
脂滴（LDs）是普遍存在的细胞器，以中性脂质（通常是三酰甘油和甾醇酯）的形式储存代谢能量。除了作为惰性的能量储存室之外，LDs 还是参与许多重要代谢功能的动态细胞器。细胞从内质网（ER）的不同亚区从头生成 LDs，但决定 LD 形成的部位仍然是一个关键的未解决问题。在这里，我们综述了决定 ER 中 LD 形成的因素，并讨论了它们如何共同协作以时空协调 LD 的生物发生。这些因素包括脂质合成酶、组装蛋白和膜结构要求。LDs 还与其他细胞器接触，这些细胞器间的接触有助于确定 LD 产生的部位。最后，我们强调了在应激过程中 LD 在维持细胞内稳态方面的新兴非典型作用。
