Becker B, Melkonian M
Botanisches Institut, Universität zu Köln, Germany.
Microbiol Rev. 1996 Dec;60(4):697-721. doi: 10.1128/mr.60.4.697-721.1996.
All cells secrete a diversity of macromolecules to modify their environment or to protect themselves. Eukaryotic cells have evolved a complex secretory pathway consisting of several membrane-bound compartments which contain specific sets of proteins. Experimental work on the secretory pathway has focused mainly on mammalian cell lines or on yeasts. Now, some general principles of the secretory pathway have become clear, and most components of the secretory pathway are conserved between yeast cells and mammalian cells. However, the structure and function of the secretory system in protists have been less extensively studied. In this review, we summarize the current knowledge about the secretory pathway of five different groups of protists: Giardia lamblia, one of the earliest lines of eukaryotic evolution, kinetoplastids, the slime mold Dictyostelium discoideum, and two lineages within the "crown" of eukaryotic cell evolution, the alveolates (ciliates and Plasmodium species) and the green algae. Comparison of these systems with the mammalian and yeast system shows that most elements of the secretory pathway were presumably present in the earliest eukaryotic organisms. However, one element of the secretory pathway shows considerable variation: the presence of a Golgi stack and the number of cisternae within a stack. We suggest that the functional separation of the plasma membrane from the nucleus-endoplasmic reticulum system during evolution required a sorting compartment, which became the Golgi apparatus. Once a Golgi apparatus was established, it was adapted to the various needs of the different organisms.
所有细胞都会分泌多种大分子来改变其周围环境或保护自身。真核细胞进化出了一条复杂的分泌途径，该途径由几个包含特定蛋白质组的膜结合区室组成。关于分泌途径的实验工作主要集中在哺乳动物细胞系或酵母上。现在，分泌途径的一些一般原则已经明确，并且分泌途径的大多数成分在酵母细胞和哺乳动物细胞之间是保守的。然而，原生生物中分泌系统的结构和功能研究较少。在这篇综述中，我们总结了目前关于五类不同原生生物分泌途径的知识：贾第虫，真核生物进化的最早谱系之一；动质体；黏菌盘基网柄菌；以及真核细胞进化“皇冠”中的两个谱系，即囊泡虫类（纤毛虫和疟原虫物种）和绿藻。将这些系统与哺乳动物和酵母系统进行比较表明，分泌途径的大多数成分可能在最早的真核生物中就已存在。然而，分泌途径的一个成分显示出相当大的差异：高尔基体堆叠的存在以及堆叠中潴泡的数量。我们认为，在进化过程中质膜与细胞核 - 内质网系统的功能分离需要一个分拣区室，它后来成为了高尔基体。一旦高尔基体建立起来，它就适应了不同生物体的各种需求。
