Institute of Medical Microbiology and Hygiene, Medical Center-University of Freiburg, Faculty of Medicine, 79104 Freiburg, Germany.
Int J Med Microbiol. 2018 Jan;308(1):25-31. doi: 10.1016/j.ijmm.2017.07.010. Epub 2017 Jul 29.
Septins are a relatively little understood group of GTPases that form large assemblies in cells from all eukaryotes other than plants. Septins were first identified in cell division but have also been implicated in microbial infections. Septins often associate with cytoskeletal proteins - most often described for filamentous (F-) actin - and are considered cytoskeletal components themselves. Septins have increasingly been found to partake in processes that are linked to intracellular membranes, from mitochondria to phagosomes, and evidence is accumulating that septins specifically bind to membranes. Since a number of microorganisms have specialized to live and grow inside membranous vacuoles in the cytosol of mammalian cells, this membrane-association of septins suggests that septins may also be involved in the membranous, vacuolar structures that develop around these microbes. However, data are limited on this issue: septins have been identified by proteome analysis on some microbe-bearing vacuoles, but more extensive experimental data are only available for infections with the obligate intracellular bacterium Chlamydia trachomatis. In this review article I will discuss the available data and speculate about the mechanisms of recruitment and potential functions of septins for vacuole-dwelling microorganisms, which may be peculiar to Chlamydia or may pertain more generally to this class of microbes.
septins 是一组相对不太了解的 GTPases，它们在除植物以外的所有真核生物的细胞中形成大型组装体。 septins 最初在细胞分裂中被发现，但也与微生物感染有关。 septins 通常与细胞骨架蛋白相关联 - 最常描述为丝状（F-）肌动蛋白 - 并被认为是细胞骨架成分本身。 septins 越来越多地被发现参与与细胞内膜相关的过程，从线粒体到吞噬体，并且有证据表明 septins 特异性地与膜结合。由于许多微生物已经专门适应在哺乳动物细胞质膜囊泡中生存和生长，因此 septins 的这种膜结合表明 septins 也可能参与围绕这些微生物形成的膜囊泡结构。然而，关于这个问题的数据有限：在一些带有微生物的囊泡上通过蛋白质组分析已经鉴定出 septins，但更广泛的实验数据仅可用于与必需的细胞内细菌沙眼衣原体的感染。在这篇综述文章中，我将讨论可用的数据，并推测 septins 对居住在囊泡中的微生物的招募机制和潜在功能，这可能是沙眼衣原体特有的，也可能更普遍地适用于这类微生物。
