The production of membrane proteins of high purity and in satisfactory yields is crucial for biomedical research. Due to their involvement in various cellular processes, membrane proteins have increasingly become some of the most important drug targets in modern times. Therefore, their structural and functional characterization is a high priority. However, protein expression has always been more challenging for membrane proteins than for soluble proteins. In this review, we present four of the most commonly-used expression systems for eukaryotic membrane proteins. We describe the benefits and drawbacks of bacterial, yeast, insect and mammalian cells. In addition, we describe the different features (growth rate, yield, post-translational modifications) of each expression system, and how they are influenced by the construct design and modifications of the target gene. Cost-effective and fast-growing E. coli is mostly selected for the production of small, simple membrane proteins that, if possible, do not require post-translational modifications but has the potential for the production of bigger proteins as well. Yeast hosts are advantageous for larger and more complex proteins but for the most complex ones, insect or mammalian cells are used as they are the only hosts able to perform all the post-translational modifications found in human cells. A combination of rational construct design and host cell choice can dramatically improve membrane protein production processes.

中文翻译：

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真核和原核宿主中真核膜蛋白的表达

生产高纯度和令人满意的产率的膜蛋白对于生物医学研究至关重要。由于它们参与各种细胞过程，膜蛋白越来越成为现代最重要的药物靶点。因此，它们的结构和功能表征是重中之重。然而，膜蛋白的蛋白表达一直比可溶性蛋白更具挑战性。在这篇综述中，我们介绍了四种最常用的真核膜蛋白表达系统。我们描述了细菌、酵母、昆虫和哺乳动物细胞的优点和缺点。此外，我们描述了每个表达系统的不同特征（生长率、产量、翻译后修饰），以及它们如何受到目标基因的构建体设计和修饰的影响。经济高效且生长迅速的大肠杆菌主要用于生产小型、简单的膜蛋白，如果可能，这些膜蛋白不需要翻译后修饰，但也有可能生产更大的蛋白质。酵母宿主有利于更大和更复杂的蛋白质，但对于最复杂的蛋白质，使用昆虫或哺乳动物细胞，因为它们是唯一能够执行人类细胞中发现的所有翻译后修饰的宿主。合理的构建设计和宿主细胞选择的结合可以显着改善膜蛋白的生产过程。不需要翻译后修饰，但也有生产更大蛋白质的潜力。酵母宿主有利于更大和更复杂的蛋白质，但对于最复杂的蛋白质，使用昆虫或哺乳动物细胞，因为它们是唯一能够执行人类细胞中发现的所有翻译后修饰的宿主。合理的构建设计和宿主细胞选择的结合可以显着改善膜蛋白的生产过程。不需要翻译后修饰，但也有生产更大蛋白质的潜力。酵母宿主有利于更大和更复杂的蛋白质，但对于最复杂的蛋白质，使用昆虫或哺乳动物细胞，因为它们是唯一能够执行人类细胞中发现的所有翻译后修饰的宿主。合理的构建设计和宿主细胞选择的结合可以显着改善膜蛋白的生产过程。