Two dynamin-like proteins stabilize FtsZ rings during Streptomyces sporulation
Two dynamin-like proteins stabilize FtsZ rings during Streptomyces sporulation
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DOI：
10.1073/pnas.1704612114
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发表时间：
2017-07-25
影响因子：
11.1
通讯作者：
Buttner, Mark J.
中科院分区：
文献类型：
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作者：
Schlimpert, Susan;Wasserstrom, Sebastian;Buttner, Mark J.
在孢子形成过程中，丝状细菌链霉菌经历了大规模的细胞分裂活动，在这个过程中，孢子形成隔膜的梯子的合成将多基因组菌丝转化为非基因组孢子链。这一过程需要细菌微管蛋白同系物FtsZ形成细胞动力学Z环，而新形成的Z环的稳定是完成隔膜合成的关键。在这里，我们展示了两个动力素样蛋白，DyNA和DyB，在这一过程中发挥关键作用。动力蛋白是一个大的、多结构域的GTP酶家族，参与真核生物的关键细胞过程，包括囊泡运输和细胞器分裂。许多细菌基因组编码动力蛋白样蛋白，但这些蛋白的生物学功能在很大程度上仍然是个谜。利用细胞生物学方法，我们证明了这两个链霉菌动力素以FtsZ依赖的方式特异性地定位于孢子形成隔膜。此外，动态蛋白突变体具有细胞分裂缺陷，这是由于孢子形成特异性Z环的稳定性降低所致，从FtsZ梯形图的时间推移图像中可以看出这一点。这一缺陷导致单个Z环过早解体，导致隔膜合成频繁流产，进而产生具有多条染色体的长孢子状隔室。双杂交分析表明，动力素是细胞分裂机制的一部分，它们通过涉及dyNA、dyn B、FtsZ、SepF、SepF2和FtsZ定位蛋白SsgB的蛋白质-蛋白质相互作用网络，在发育受控的细胞分裂过程中介导它们对Z环稳定性的影响。
During sporulation, the filamentous bacteria Streptomyces undergo a massive cell division event in which the synthesis of ladders of sporulation septa convert multigenomic hyphae into chains of unigenomic spores. This process requires cytokinetic Z-rings formed by the bacterial tubulin homolog FtsZ, and the stabilization of the newly formed Z-rings is crucial for completion of septum synthesis. Here we show that two dynamin-like proteins, DynA and DynB, play critical roles in this process. Dynamins are a family of large, multidomain GTPases involved in key cellular processes in eukaryotes, including vesicle trafficking and organelle division. Many bacterial genomes encode dynamin-like proteins, but the biological function of these proteins has remained largely enigmatic. Using a cell biological approach, we show that the two Streptomyces dynamins specifically localize to sporulation septa in an FtsZ-dependent manner. Moreover, dynamin mutants have a cell division defect due to the decreased stability of sporulation-specific Z-rings, as demonstrated by kymographs derived from time-lapse images of FtsZ ladder formation. This defect causes the premature disassembly of individual Z-rings, leading to the frequent abortion of septum synthesis, which in turn results in the production of long spore-like compartments with multiple chromosomes. Two-hybrid analysis revealed that the dynamins are part of the cell division machinery and that they mediate their effects on Z-ring stability during developmentally controlled cell division via a network of protein-protein interactions involving DynA, DynB, FtsZ, SepF, SepF2, and the FtsZ-positioning protein SsgB.