Department of Molecular Biology, Princeton University, 310 Lewis Thomas Laboratory, Washington Road, Princeton, NJ, 08544, USA.
Protein J. 2019 Jun;38(3):217-228. doi: 10.1007/s10930-019-09813-y.
Cells in all domains of life must translocate newly synthesized proteins both across membranes and into membranes. In eukaryotes, proteins are translocated into the lumen of the ER or the ER membrane. In prokaryotes, proteins are translocated into the cytoplasmic membrane or through the membrane into the periplasm for Gram-negative bacteria or the extracellular space for Gram-positive bacteria. Much of what we know about protein translocation was learned through genetic selections and screens utilizing lacZ gene fusions in Escherichia coli. This review covers the basic principles of protein translocation and how they were discovered and developed. In particular, we discuss how lacZ gene fusions and the phenotypes conferred were exploited to identify the genes involved in protein translocation and provide insights into their mechanisms of action. These approaches, which allowed the elucidation of processes that are conserved throughout the domains of life, illustrate the power of seemingly simple experiments.
所有生命领域的细胞都必须将新合成的蛋白质穿过膜并进入膜内进行转运。在真核生物中，蛋白质被转运到内质网腔或内质网膜中。在原核生物中，蛋白质被转运到细胞质膜中，或者通过膜进入革兰氏阴性菌的周质空间或革兰氏阳性菌的细胞外空间。我们对蛋白质转运的大部分了解都是通过利用大肠杆菌中 lacZ 基因融合的遗传选择和筛选获得的。这篇综述涵盖了蛋白质转运的基本原理，以及它们是如何被发现和发展的。特别是，我们讨论了如何利用 lacZ 基因融合和所赋予的表型来鉴定参与蛋白质转运的基因，并深入了解它们的作用机制。这些方法阐明了贯穿生命领域的保守过程，展示了看似简单的实验的强大力量。
