The biology of mycobacteria is dominated by a complex cell envelope of unique composition and structure and of exceptionally low permeability. This cell envelope is the basis of many of the pathogenic features of mycobacteria and the site of susceptibility and resistance to many antibiotics and host defense mechanisms. This review is focused on the transporters that assemble and functionalize this complex structure. It highlights both the progress and the limits of our understanding of how (lipo)polysaccharides, (glyco)lipids, and other bacterial secretion products are translocated across the different layers of the cell envelope to their final extra-cytoplasmic location. It further describes some of the unique strategies evolved by mycobacteria to import nutrients and other products through this highly impermeable barrier.

中文翻译：

---

参与分枝杆菌细胞包膜生物发生和功能化的转运蛋白

分枝杆菌的生物学以具有独特组成和结构且渗透性极低的复杂细胞包膜为主。这种细胞包膜是分枝杆菌许多致病特征的基础，也是对许多抗生素和宿主防御机制的敏感性和耐药性的部位。本综述的重点是组装这种复杂结构并使其功能化的转运蛋白。它强调了我们对（脂）多糖、（糖）脂质和其他细菌分泌产物如何跨细胞膜的不同层转运到其最终胞质外位置的理解的进展和局限性。它进一步描述了分枝杆菌进化出的一些独特策略，通过这种高度不可渗透的屏障输入营养物质和其他产品。