MamK, a bacterial actin, forms dynamic filaments in vivo that are regulated by the acidic proteins MamJ and LimJ.
MamK, a bacterial actin, forms dynamic filaments in vivo that are regulated by the acidic proteins MamJ and LimJ.
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DOI：
10.1111/j.1365-2958.2011.07815.x
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发表时间：
2011-10
影响因子：
3.6
通讯作者：
Komeili A
中科院分区：
文献类型：
--
作者：
Draper O;Byrne ME;Li Z;Keyhani S;Barrozo JC;Jensen G;Komeili A
细菌的肌动蛋白与真核生物不同，它们是高度分化的蛋白质，其广泛的功能被认为与它们的进化多样性有关。一个分支，以趋磁细菌的MamK蛋白为代表，是磁小体的亚细胞组织所必需的，磁小体是帮助沿着地球磁场导航的膜结合细胞器。利用光漂白后磁螺旋藻AMB-1的荧光恢复实验，我们发现，与传统的肌动蛋白一样，MamK形成动态细丝，需要完整的NTPase基序才能在体内进行周转。我们还发现了两个蛋白MamJ和LimJ，它们在野生型细胞中执行冗余功能以促进MamK丝的动态行为。MamJ和LimJ的缺失导致静态细丝，磁小体链断裂，以及磁小体之间细胞骨架细丝的异常积聚。我们的研究结果表明，MamK丝和真核生物的肌动蛋白一样，本质上是稳定的，它们的动态行为依赖于调节因子，这一特征与迄今为止表征的某些细菌肌动蛋白不同。
Bacterial actins, in contrast to their eukaryotic counterparts, are highly divergent proteins whose wide-ranging functions are thought to correlate with their evolutionary diversity. One clade, represented by the MamK protein of magnetotactic bacteria, is required for the subcellular organization of magnetosomes, membrane-bound organelles that aid in navigation along the earth’s magnetic field. Using a fluorescence recovery after photobleaching assay in Magnetospirillum magneticum AMB-1, we find that, like traditional actins, MamK forms dynamic filaments that require an intact NTPase motif for their turnover in vivo. We also uncover two proteins, MamJ and LimJ, which perform a redundant function to promote the dynamic behavior of MamK filaments in wildtype cells. The absence of both MamJ and LimJ leads to static filaments, a disrupted magnetosome chain, and an anomalous build-up of cytoskeletal filaments between magnetosomes. Our results suggest that MamK filaments, like eukaryotic actins, are intrinsically stable and rely on regulators for their dynamic behavior, a feature that stands in contrast to some classes of bacterial actins characterized to date.
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影响因子：
3.6
作者：
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通讯作者：
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影响因子：
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作者：
Leong, PA;Heymann, JB;Jensen, GJ
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影响因子：
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作者：
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影响因子：
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作者：
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通讯作者：
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DOI：
10.1073/pnas.0604503103
发表时间：
2006-07-18
影响因子：
11.1
作者：
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通讯作者：
Moerner, W. E.