van der Rest M E, Kamminga A H, Nakano A, Anraku Y, Poolman B, Konings W N
Department of Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Haren, The Netherlands.
Microbiol Rev. 1995 Jun;59(2):304-22. doi: 10.1128/mr.59.2.304-322.1995.
The composition of phospholipids, sphingolipids, and sterols in the plasma membrane has a strong influence on the activity of the proteins associated or embedded in the lipid bilayer. Since most lipid-synthesizing enzymes in Saccharomyces cerevisiae are located in intracellular organelles, an extensive flux of lipids from these organelles to the plasma membrane is required. Although the pathway of protein traffic to the plasma membrane is similar to that of most of the lipids, the bulk flow of lipids is separate from vesicle-mediated protein transport. Recent advances in the analysis of membrane budding and membrane fusion indicate that the mechanisms of protein transport from the endoplasmic reticulum to the Golgi and from the Golgi to plasma membrane are similar. The majority of plasma membrane proteins transport solutes across the membrane. A number of ATP-dependent export systems have been detected that couple the hydrolysis of ATP to transport of molecules out of the cell. The hydrolysis of ATP by the plasma membrane H(+)-ATPase generates a proton motive force which is used to drive secondary transport processes. In S. cerevisiae, many substrates are transported by more than one system. Transport of monosaccharide is catalyzed by uniport systems, while transport of disaccharides, amino acids, and nucleosides is mediated by proton symport systems. Transport activity can be regulated at the level of transcription, e.g., induction and (catabolite) repression, but transport proteins can also be affected posttranslationally by a process termed catabolite inactivation. Catabolite inactivation is triggered by the addition of fermentable sugars, intracellular acidification, stress conditions, and/or nitrogen starvation. Phosphorylation and/or ubiquitination of the transport proteins has been proposed as an initial step in the controlled inactivation and degradation of the target enzyme. The use of artificial membranes, like secretory vesicles and plasma membranes fused with proteoliposomes, as model systems for studies on the mechanism and regulation of transport is evaluated.
质膜中磷脂、鞘脂和固醇的组成对与脂质双层相关或嵌入其中的蛋白质活性有很大影响。由于酿酒酵母中的大多数脂质合成酶位于细胞内细胞器中，因此需要大量脂质从这些细胞器流向质膜。尽管蛋白质运输到质膜的途径与大多数脂质的途径相似，但脂质的大量流动与囊泡介导的蛋白质运输是分开的。膜出芽和膜融合分析的最新进展表明，蛋白质从内质网运输到高尔基体以及从高尔基体运输到质膜的机制是相似的。大多数质膜蛋白跨膜运输溶质。已经检测到许多依赖ATP的输出系统，这些系统将ATP的水解与分子从细胞中运输出去耦合起来。质膜H(+)-ATPase水解ATP产生质子动力，用于驱动次级运输过程。在酿酒酵母中，许多底物由不止一种系统运输。单糖的运输由单向运输系统催化，而二糖、氨基酸和核苷的运输由质子同向运输系统介导。运输活性可以在转录水平上进行调节，例如诱导和（分解代谢）阻遏，但运输蛋白也可以在翻译后受到一种称为分解代谢失活的过程的影响。分解代谢失活由可发酵糖的添加、细胞内酸化、应激条件和/或氮饥饿触发。运输蛋白的磷酸化和/或泛素化被认为是靶酶受控失活和降解的初始步骤。评估了使用人工膜，如分泌囊泡和与蛋白脂质体融合的质膜，作为研究运输机制和调节的模型系统。
