ZapA and ZapB form an FtsZ-independent structure at midcell.
ZapA and ZapB form an FtsZ-independent structure at midcell.
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DOI：
10.1111/mmi.13655
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发表时间：
2017-05
影响因子：
3.6
通讯作者：
Bernhardt TG
中科院分区：
文献类型：
--
作者：
Buss JA;Peters NT;Xiao J;Bernhardt TG
大肠杆菌中的细胞分裂始于 FtsZ 在细胞中部聚合成环状结构（Z 环）。所有其他分裂蛋白被认为需要 Z 环来招募到未来的分裂位点。在这里，我们报告 Z 环相关蛋白 ZapA 和 ZapB 在中细胞形成 FtsZ 独立结构。当 Z 环被 FtsZ 聚合拮抗剂 SulA 破坏后，ZapA 以云状积累形式保留在细胞中部。使用 ZapA(N60Y)（一种与 FtsZ 相互作用有缺陷的变体），确定这些 ZapA 结构在不与 Z 环连接的情况下形成。此外，GFP-ZapA(N60Y) 的细胞中积累通常先于细胞中的 Z 环，并且需要 ZapB 进行组装，这表明 ZapB 聚合物形成了这些结构的基础。在 MatP（一种将 ZapB 连接到染色体末端区域的 DNA 结合蛋白）缺失的情况下，云状 ZapA 结构仍然形成，但无法追踪染色体末端，并且在中细胞处并不始终先于 FtsZ。综上所述，我们的结果表明，ZapA-ZapB 的 FtsZ 独立结构为 Z 环的形成提供了额外的位置线索，并可能有助于协调其组装与染色体复制和分离。我们发现大肠杆菌的 FtsZ 环相关蛋白 ZapA 在细胞中部形成依赖于 ZapB 的 FtsZ 独立结构。此外，这些 ZapA-ZapB 结构能够在 FtsZ 环聚合之前识别新的分裂位点，并且这种现象很大程度上依赖于 ter 结合蛋白 MatP。综上所述，我们的结果表明，ZapA-ZapB 的 FtsZ 独立结构为 FtsZ 环的形成提供了额外的位置线索，并可能有助于协调其组装与染色体复制和分离。
Cell division in Escherichia coli begins with the polymerization of FtsZ into a ring-like structure, the Z-ring, at midcell. All other division proteins are thought to require the Z-ring for recruitment to the future division site. Here, we report that the Z-ring associated proteins ZapA and ZapB form FtsZ-independent structures at midcell. Upon Z-ring disruption by the FtsZ polymerization antagonist SulA, ZapA remained at midcell as a cloud-like accumulation. Using ZapA(N60Y), a variant defective for interaction with FtsZ, it was established that these ZapA structures form without a connection to the Z-ring. Furthermore, midcell accumulations of GFP-ZapA(N60Y) often preceded Z-rings at midcell and required ZapB to assemble, suggesting that ZapB polymers form the foundation of these structures. In the absence of MatP, a DNA-binding protein that links ZapB to the chromosomal terminus region, cloud-like ZapA structures still formed but failed to track with the chromosome terminus and did not consistently precede FtsZ at midcell. Taken together, our results suggest that FtsZ-independent structures of ZapA-ZapB provide additional positional cues for Z-ring formation and may help coordinate its assembly with chromosome replication and segregation. We found that E. coli’s FtsZ-ring associated protein ZapA forms FtsZ-independent structures at midcell that are dependent on ZapB. Furthermore, these ZapA-ZapB structures are capable of identifying new sites of division prior to polymerization of the FtsZ-ring and this phenomenon is largely dependent on the ter-binding protein, MatP. Taken together, our results suggest that FtsZ-independent structures of ZapA-ZapB provide additional positional cues for FtsZ-ring formation and may help coordinate its assembly with chromosome replication and segregation.