Neumann Ulla, Brandizzi Federica, Hawes Chris
Research School of Biological and Molecular Sciences, Oxford Brookes University, Gipsy Lane Campus,Oxford OX3 0BP, UK.
Ann Bot. 2003 Aug;92(2):167-80. doi: 10.1093/aob/mcg134.
In plant cells, the Golgi apparatus is the key organelle for polysaccharide and glycolipid synthesis, protein glycosylation and protein sorting towards various cellular compartments. Protein import from the endoplasmic reticulum (ER) is a highly dynamic process, and new data suggest that transport, at least of soluble proteins, occurs via bulk flow. In this Botanical Briefing, we review the latest data on ER/Golgi inter-relations and the models for transport between the two organelles. Whether vesicles are involved in this transport event or if direct ER-Golgi connections exist are questions that are open to discussion. Whereas the majority of proteins pass through the Golgi on their way to other cell destinations, either by vesicular shuttles or through maturation of cisternae from the cis- to the trans-face, a number of membrane proteins reside in the different Golgi cisternae. Experimental evidence suggests that the length of the transmembrane domain is of crucial importance for the retention of proteins within the Golgi. In non-dividing cells, protein transport out of the Golgi is either directed towards the plasma membrane/cell wall (secretion) or to the vacuolar system. The latter comprises the lytic vacuole and protein storage vacuoles. In general, transport to either of these from the Golgi depends on different sorting signals and receptors and is mediated by clathrin-coated and dense vesicles, respectively. Being at the heart of the secretory pathway, the Golgi (transiently) accommodates regulatory proteins of secretion (e.g. SNAREs and small GTPases), of which many have been cloned in plants over the last decade. In this context, we present a list of regulatory proteins, along with structural and processing proteins, that have been located to the Golgi and the 'trans-Golgi network' by microscopy.
在植物细胞中，高尔基体是多糖和糖脂合成、蛋白质糖基化以及蛋白质分选至不同细胞区室的关键细胞器。从内质网（ER）导入蛋白质是一个高度动态的过程，新数据表明，至少可溶性蛋白质的运输是通过整体流动进行的。在本植物学简报中，我们综述了关于内质网/高尔基体相互关系以及这两个细胞器之间运输模型的最新数据。囊泡是否参与这一运输过程，或者内质网与高尔基体之间是否存在直接连接，这些问题尚有待讨论。大多数蛋白质在前往其他细胞目的地的途中会经过高尔基体，要么通过囊泡穿梭，要么通过扁平囊泡从顺面到反面的成熟过程，而一些膜蛋白则驻留在不同的高尔基体扁平囊泡中。实验证据表明，跨膜结构域的长度对于蛋白质在高尔基体中的保留至关重要。在非分裂细胞中，从高尔基体输出的蛋白质要么导向质膜/细胞壁（分泌），要么导向液泡系统。后者包括溶酶体和蛋白质储存液泡。一般来说，从高尔基体向这两者的运输分别取决于不同的分选信号和受体，并分别由网格蛋白包被的囊泡和致密囊泡介导。作为分泌途径的核心，高尔基体（暂时）容纳分泌的调节蛋白（如SNARE蛋白和小GTP酶），在过去十年中，许多这类蛋白已在植物中克隆出来。在此背景下，我们列出了通过显微镜定位到高尔基体和“反式高尔基体网络”的调节蛋白，以及结构蛋白和加工蛋白。
