Multi-functional regulator MapZ controls both positioning and timing of FtsZ polymerization
Multi-functional regulator MapZ controls both positioning and timing of FtsZ polymerization
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多功能调节器 MapZ 控制 FtsZ 聚合的定位和时间
DOI：
10.1042/bcj20190138
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发表时间：
2019-05-31
影响因子：
4.1
通讯作者：
Chen, Yuxing
中科院分区：
文献类型：
--
作者：
Feng, Zhang;Zhang, Jiahai;Chen, Yuxing
微管蛋白样GTP酶蛋白FtsZ在细胞中期形成一个不连续的细胞动力学环，是募集分裂机制以协调细胞分裂的核心参与者。为了保证两个相同的子细胞的生产，FtsZ的组装，即Z环，及其精确定位应该被精细地调节。在肺炎链球菌（Streptococcus pneumoniae）中，Z环在分裂位点的定位由双位膜蛋白MapZ（mid-cell-anchored protein Z）通过胞内结构域（称为MapZ-N（MapZ的胞内结构域））和FtsZ之间的直接相互作用介导。使用核磁共振滴定实验，我们清楚地分配参与相互作用的关键残基。在MapZ-N的存在下，FtsZ获得了缩短的活化延迟，较低的聚合临界浓度和对GTP水解的较高协同性。另一方面，MapZ-N拮抗FtsZ的单链细丝的横向相互作用，从而减缓高度成束的FtsZ聚合物的形成，并最终保持FtsZ处于动态状态。总之，我们得出结论，MapZ不仅是一个加速器，触发聚合的FtsZ，但也是一个刹车，调整速度，形成最终产品，FtsZ束。这些研究结果表明，MapZ是一个多功能的调节FtsZ，控制精确定位和适当的定时FtsZ聚合。
The tubulin-like GTPase protein FtsZ, which forms a discontinuous cytokinetic ring at mid-cell, is a central player to recruit the division machinery to orchestrate cell division. To guarantee the production of two identical daughter cells, the assembly of FtsZ, namely Z-ring, and its precise positioning should be finely regulated. In Streptococcus pneumoniae, the positioning of Z-ring at the division site is mediated by a bitopic membrane protein MapZ (mid-cell-anchored protein Z) through direct interactions between the intracellular domain (termed MapZ-N (the intracellular domain of MapZ)) and FtsZ. Using nuclear magnetic resonance titration experiments, we clearly assigned the key residues involved in the interactions. In the presence of MapZ-N, FtsZ gains a shortened activation delay, a lower critical concentration for polymerization and a higher cooperativity towards GTP hydrolysis. On the other hand, MapZ-N antagonizes the lateral interactions of single-stranded filaments of FtsZ, thus slows down the formation of highly bundled FtsZ polymers and eventually maintains FtsZ at a dynamic state. Altogether, we conclude that MapZ is not only an accelerator to trigger the polymerization of FtsZ, but also a brake to tune the velocity to form the end-product, FtsZ bundles. These findings suggest that MapZ is a multi-functional regulator towards FtsZ that controls both the precise positioning and proper timing of FtsZ polymerization.