Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, Université de Paris, LBPC-PM, CNRS, UMR7099, 75005 Paris, France.
Institut de Biologie Physico-Chimique, Fondation Edmond de Rothschild pour le Développement de la Recherche Scientifique, 75005 Paris, France.
Toxins (Basel). 2021 May 11;13(5):341. doi: 10.3390/toxins13050341.
The type 5 secretion system (T5SS) is one of the more widespread secretion systems in Gram-negative bacteria. Proteins secreted by the T5SS are functionally diverse (toxins, adhesins, enzymes) and include numerous virulence factors. Mechanistically, the T5SS has long been considered the simplest of secretion systems, due to the paucity of proteins required for its functioning. Still, despite more than two decades of study, the exact process by which T5SS substrates attain their final destination and correct conformation is not totally deciphered. Moreover, the recent addition of new sub-families to the T5SS raises additional questions about this secretion mechanism. Central to the understanding of type 5 secretion is the question of protein folding, which needs to be carefully controlled in each of the bacterial cell compartments these proteins cross. Here, the biogenesis of proteins secreted by the Type 5 secretion system is discussed, with a focus on the various factors preventing or promoting protein folding during biogenesis.
5 型分泌系统（T5SS）是革兰氏阴性菌中更为广泛分布的分泌系统之一。T5SS 分泌的蛋白质具有多种功能（毒素、黏附素、酶），包括许多毒力因子。从机制上讲，由于 T5SS 发挥功能所需的蛋白质很少，因此它长期以来被认为是最简单的分泌系统之一。尽管经过了二十多年的研究，但 T5SS 底物达到最终目的地并形成正确构象的确切过程仍未完全破译。此外，最近 T5SS 新增了一些亚家族，这对该分泌机制提出了更多的问题。理解 5 型分泌的核心问题是蛋白质折叠的问题，这需要在这些蛋白质穿过的每个细菌细胞区室中进行仔细控制。本文讨论了由 5 型分泌系统分泌的蛋白质的生物发生，重点介绍了在生物发生过程中防止或促进蛋白质折叠的各种因素。
