LocZ is a new cell division protein involved in proper septum placement in Streptococcus pneumoniae.
LocZ is a new cell division protein involved in proper septum placement in Streptococcus pneumoniae.
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DOI：
10.1128/mbio.01700-14
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发表时间：
2014-12-30
期刊：
影响因子：
6.4
通讯作者：
Branny P
中科院分区：
文献类型：
--
作者：
Holečková N;Doubravová L;Massidda O;Molle V;Buriánková K;Benada O;Kofroňová O;Ulrych A;Branny P
细菌如何控制中细胞的正确隔膜位置，以保证相同子细胞的产生，目前仍不清楚。尽管在选定的物种中描述了涉及分裂位点选择的不同系统，但这些系统似乎并未广泛保守。在这里，我们报道了 LocZ (Spr0334)，一种新鉴定的细胞分裂蛋白，参与肺炎链球菌中隔膜的正确放置。我们证明locZ不是必需的，但它的缺失会导致细胞分裂缺陷和形状变形，导致细胞不对称分裂并产生大小不等、偶尔无核的子细胞。 LocZ 具有独特的本地化配置文件。它在 FtsZ 和 FtsA 之前提前到达中细胞，并提前离开隔膜，显然是沿着标记未来分裂位点的赤道环移动。一致的是，缺乏 LocZ 的细胞也显示出 Z 环的错位，这表明它可以充当确定隔膜位置的正调节因子。 LocZ 被鉴定为 Ser/Thr 蛋白激酶 StkP 的底物，它调节肺炎链球菌的细胞分裂。有趣的是，LocZ 的同源物仅在链球菌、乳球菌和肠球菌中发现，表明这种系统发育密切相关的细菌群进化出了一种特定的解决方案来空间调节细胞分裂。细菌细胞分裂是一个在时间和空间上受到调节的高度有序的过程。最近，我们报道了 Ser/Thr 蛋白激酶 StkP 通过几种关键蛋白的磷酸化来调节肺炎链球菌的细胞分裂。在这里，我们对 StkP 底物之一 Spr0334 进行了表征，我们将其命名为 LocZ。我们证明 LocZ 是一种新的细胞分裂蛋白，对于正确的隔膜放置很重要，并且可能作为细胞分裂位点的标记。始终如一，LocZ 支持在 midcell 处正确定位 Z 形环。 LocZ 仅在链球菌、乳球菌和肠球菌中保守，这些细菌缺乏 Min 和类核闭塞效应子的同源物，表明这些细菌采用了独特的机制来寻找它们的中间，反映了它们特定的形状和对称性。
How bacteria control proper septum placement at midcell, to guarantee the generation of identical daughter cells, is still largely unknown. Although different systems involved in the selection of the division site have been described in selected species, these do not appear to be widely conserved. Here, we report that LocZ (Spr0334), a newly identified cell division protein, is involved in proper septum placement in Streptococcus pneumoniae. We show that locZ is not essential but that its deletion results in cell division defects and shape deformation, causing cells to divide asymmetrically and generate unequally sized, occasionally anucleated, daughter cells. LocZ has a unique localization profile. It arrives early at midcell, before FtsZ and FtsA, and leaves the septum early, apparently moving along with the equatorial rings that mark the future division sites. Consistently, cells lacking LocZ also show misplacement of the Z-ring, suggesting that it could act as a positive regulator to determine septum placement. LocZ was identified as a substrate of the Ser/Thr protein kinase StkP, which regulates cell division in S. pneumoniae. Interestingly, homologues of LocZ are found only in streptococci, lactococci, and enterococci, indicating that this close phylogenetically related group of bacteria evolved a specific solution to spatially regulate cell division. Bacterial cell division is a highly ordered process regulated in time and space. Recently, we reported that the Ser/Thr protein kinase StkP regulates cell division in Streptococcus pneumoniae, through phosphorylation of several key proteins. Here, we characterized one of the StkP substrates, Spr0334, which we named LocZ. We show that LocZ is a new cell division protein important for proper septum placement and likely functions as a marker of the cell division site. Consistently, LocZ supports proper Z-ring positioning at midcell. LocZ is conserved only among streptococci, lactococci, and enterococci, which lack homologues of the Min and nucleoid occlusion effectors, indicating that these bacteria adapted a unique mechanism to find their middle, reflecting their specific shape and symmetry.