Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan.
J Exp Bot. 2022 May 13;73(9):2835-2847. doi: 10.1093/jxb/erac063.
Organisms, including humans, seem to be constantly exposed to various changes, which often have undesirable effects, referred to as stress. To keep up with these changes, eukaryotic cells may have evolved a number of relevant cellular processes, such as the endoplasmic reticulum (ER) stress response. Owing to presumably intimate links between human diseases and the ER function, the ER stress response has been extensively investigated in various organisms for a few decades. Based on these studies, we now have a picture of the molecular mechanisms of the ER stress response, one of which, the unfolded protein response (UPR), is highly conserved among yeasts, mammals, higher plants, and green algae. In this review, we attempt to highlight the plant UPR from the perspective of lipids, especially membrane phospholipids. Phosphatidylcholine (PtdCho) and phosphatidylethanolamine (PtdEtn) are the most abundant membrane phospholipids in eukaryotic cells. The ratio of PtdCho to PtdEtn and the unsaturation of fatty acyl tails in both phospholipids may be critical factors for the UPR, but the pathways responsible for PtdCho and PtdEtn biosynthesis are distinct in animals and plants. We discuss the plant UPR in comparison with the system in yeasts and animals in the context of membrane phospholipids.
生物体，包括人类，似乎不断地暴露在各种变化中，这些变化往往会产生不良影响，被称为应激。为了适应这些变化，真核细胞可能已经进化出了许多相关的细胞过程，例如内质网（ER）应激反应。由于人类疾病与 ER 功能之间可能存在密切联系，因此几十年来，各种生物体的 ER 应激反应都得到了广泛的研究。基于这些研究，我们现在对 ER 应激反应的分子机制有了一个了解，其中之一是未折叠蛋白反应（UPR），它在酵母、哺乳动物、高等植物和绿藻中高度保守。在这篇综述中，我们试图从脂质，特别是膜磷脂的角度来强调植物 UPR。磷脂酰胆碱（PtdCho）和磷脂酰乙醇胺（PtdEtn）是真核细胞中最丰富的膜磷脂。这两种磷脂中 PtdCho 与 PtdEtn 的比例以及脂肪酸酰基尾部的不饱和程度可能是 UPR 的关键因素，但动物和植物中负责 PtdCho 和 PtdEtn 生物合成的途径是不同的。我们将在膜磷脂的背景下，比较植物 UPR 与酵母和动物系统。
