Foo Sherman, Caspy Ido, Cezanne Alice, Bharat Tanmay A M, Baum Buzz
Cell Biology Division, Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom.
Structural Studies Division, Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom.
Proc Natl Acad Sci U S A. 2025 Jun 24;122(25):e2501044122. doi: 10.1073/pnas.2501044122. Epub 2025 Jun 18.
The surface layer or "S-layer" is a two-dimensional lattice of proteins that coats a wide range of archaea and bacteria in place of a cell wall or capsular polysaccharides. S-layers are thought to play an important role in chemically and physically insulating cells from the external environment. Here, we show that the integrity of the S-layer in is maintained as cells grow via a process of self-assembly as SlaA monomers fill gaps in the lattice. Although this lattice which is physically tethered to the membrane might be expected to hinder cell division, we show that the S-layer flattens the membrane at cytokinesis to accelerate ESCRT-III-dependent cell division-and is important for robust, successful cell divisions under conditions of mechanical stress. Taken together, these results define the rules governing S-layer self-assembly and show how a flexible lattice coat that is coupled to the underlying membrane can both provide a cell with mechanical support and help to drive rapid and functionally important changes in cell shape.
表面层或“S 层”是一种蛋白质二维晶格，它替代细胞壁或荚膜多糖覆盖多种古细菌和细菌。S 层被认为在化学和物理上使细胞与外部环境隔离方面发挥重要作用。在这里，我们表明，随着细胞生长，S 层的完整性通过自组装过程得以维持，因为 SlaA 单体填补晶格中的间隙。尽管这个物理上与膜相连的晶格可能会阻碍细胞分裂，但我们表明，S 层在胞质分裂时使膜变平，以加速依赖内体分选转运复合体 III（ESCRT-III）的细胞分裂——并且在机械应力条件下对于稳健、成功的细胞分裂很重要。综上所述，这些结果定义了控制 S 层自组装的规则，并展示了与下层膜耦合的灵活晶格涂层如何既能为细胞提供机械支持，又有助于推动细胞形状快速且具有功能重要性的变化。
