Li Xie, Li Xifeng, Fan Baofang, Zhu Cheng, Chen Zhixiang
College of Life Science, Key Laboratory of Marine Food Quality and Hazard Controlling Technology of Zhejiang Province, China Jiliang University, Hangzhou, 310018, China.
Department of Botany and Plant Pathology, Center for Plant Biology, Purdue University, West Lafayette, 47907-2054, IN, USA.
J Integr Plant Biol. 2022 Apr;64(4):821-835. doi: 10.1111/jipb.13233. Epub 2022 Mar 9.
A central role of the endoplasmic reticulum (ER) is the synthesis, folding and quality control of secretory proteins. Secretory proteins usually exit the ER to enter the Golgi apparatus in coat protein complex II (COPII)-coated vesicles before transport to different subcellular destinations. However, in plants there are specialized ER-derived vesicles (ERDVs) that carry specific proteins but, unlike COPII vesicles, can exist as independent organelles or travel to the vacuole in a Golgi-independent manner. These specialized ERDVs include protein bodies and precursor-accumulating vesicles that accumulate storage proteins in the endosperm during seed development. Specialized ERDVs also include precursor protease vesicles that accumulate amino acid sequence KDEL-tailed cysteine proteases and ER bodies in Brassicales plants that accumulate myrosinases that hydrolyzes glucosinolates. These functionally specialized ERDVs act not only as storage organelles but also as platforms for signal-triggered processing, activation and deployment of specific proteins with important roles in plant growth, development and adaptive responses. Some specialized ERDVs have also been exploited to increase production of recombinant proteins and metabolites. Here we discuss our current understanding of the functional diversity, evolutionary mechanisms and biotechnological application of specialized ERDVs, which are associated with some of the highly remarkable characteristics important to plants.
内质网（ER）的核心作用是分泌蛋白的合成、折叠和质量控制。分泌蛋白通常在内质网中合成后，通过包被蛋白复合体II（COPII）包被的囊泡进入高尔基体，然后被运输到不同的亚细胞目的地。然而，在植物中存在特殊的内质网衍生囊泡（ERDVs），它们携带特定的蛋白质，但与COPII囊泡不同，它们可以作为独立的细胞器存在，或以不依赖高尔基体的方式运输到液泡。这些特殊的ERDVs包括蛋白体和前体积累囊泡，它们在种子发育过程中在内胚乳中积累储存蛋白。特殊的ERDVs还包括前体蛋白酶囊泡，它们积累带有KDEL尾的半胱氨酸蛋白酶；以及十字花目植物中的内质网体，它们积累能水解硫代葡萄糖苷的黑芥子酶。这些功能特殊的ERDVs不仅作为储存细胞器，还作为信号触发的特定蛋白质加工、激活和部署的平台，这些蛋白质在植物生长、发育和适应性反应中发挥着重要作用。一些特殊的ERDVs也被用于提高重组蛋白和代谢物的产量。在这里，我们讨论了目前对特殊ERDVs的功能多样性、进化机制和生物技术应用的理解，这些与植物一些非常显著的特征有关。
