Department of Experimental Immunology, Amsterdam Infection & Immunity Institute, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, Amsterdam, the Netherlands.
Mol Microbiol. 2020 Jan;113(1):4-21. doi: 10.1111/mmi.14409. Epub 2019 Nov 24.
The PE and PPE proteins of Mycobacterium tuberculosis have been studied with great interest since their discovery. Named after the conserved proline (P) and glutamic acid (E) residues in their N-terminal domains, these proteins are postulated to perform wide-ranging roles in virulence and immune modulation. However, technical challenges in studying these proteins and their encoding genes have hampered the elucidation of molecular mechanisms and leave many open questions regarding the biological functions mediated by these proteins. Here, I review the shared and unique characteristics of PE and PPE proteins from a molecular perspective linking this information to their functions in mycobacterial virulence. I discuss how the different subgroups (PE_PGRS, PPE-PPW, PPE-SVP and PPE-MPTR) are defined and why this classification of paramount importance to understand the PE and PPE proteins as individuals and or groups. The goal of this MicroReview is to summarize and structure the existing information on this gene family into a simplified framework of thinking about PE and PPE proteins and genes. Thereby, I hope to provide helpful starting points in studying these genes and proteins for researchers with different backgrounds. This has particular implications for the design and monitoring of novel vaccine candidates and in understanding the evolution of the M. tuberculosis complex.
结核分枝杆菌的 PE 和 PPE 蛋白自发现以来一直受到极大关注。这些蛋白因其 N 端结构域中保守的脯氨酸（P）和谷氨酸（E）残基而得名，据推测它们在毒力和免疫调节方面发挥着广泛的作用。然而，研究这些蛋白及其编码基因的技术挑战阻碍了对分子机制的阐明，使得许多关于这些蛋白介导的生物学功能的问题仍未解决。在这里，我从分子角度回顾了 PE 和 PPE 蛋白的共同和独特特征，并将这些信息与它们在分枝杆菌毒力中的功能联系起来。我讨论了如何定义不同的亚群（PE_PGRS、PPE-PPW、PPE-SVP 和 PPE-MPTR），以及为什么这种分类对理解 PE 和 PPE 蛋白作为个体或群体至关重要。本次综述的目的是将关于该基因家族的现有信息总结并构建为一个简化的思考框架，以了解 PE 和 PPE 蛋白和基因。希望这能为具有不同背景的研究人员研究这些基因和蛋白提供有价值的起点。这对于设计和监测新型疫苗候选物以及理解结核分枝杆菌复合体的进化具有特殊意义。
