FisB mediates membrane fission during sporulation in Bacillus subtilis
FisB mediates membrane fission during sporulation in Bacillus subtilis
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DOI：
10.1101/gad.209049.112
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发表时间：
2013-02-01
影响因子：
10.5
通讯作者：
Rudner, David Z.
中科院分区：
文献类型：
--
作者：
Doan, Thierry;Coleman, Jeff;Rudner, David Z.
细菌在生长和分化过程中如何催化膜分裂是原核细胞生物学中的一个突出问题。在这里，我们描述了一种蛋白质（FisB，为裂变蛋白B），介导膜分裂过程中的形态学过程中的芽孢形成在枯草芽孢杆菌。产孢细胞不对称分裂，产生一个大的母细胞和较小的前孢子。分裂后，母细胞膜以一种类似吞噬细胞的方式围绕前孢子迁移，称为吞噬。膜分裂释放前孢子进入母细胞的细胞质。缺乏FisB的细胞在裂变反应中严重受损。此外，GFP-FisB形成动态焦点，其固定在裂变位点。纯化的FisB在体外催化脂质混合，并且仅在其中一个融合膜中需要，这表明FisB-脂质相互作用驱动膜重塑。与这一想法相一致的是，FisB的胞质外结构域以显著的特异性与心磷脂结合，心磷脂是一种富含吞噬膜和负曲率区域的脂质。我们建议，在吞噬和FisB-心磷脂相互作用的最后阶段的膜拓扑结构，确保在正确的时间和地点切断母细胞膜。FisB的独特性质将其与真核生物中已知的裂变机制区分开来，这表明它代表了一类新的裂变蛋白。
How bacteria catalyze membrane fission during growth and differentiation is an outstanding question in prokaryotic cell biology. Here, we describe a protein (FisB, for fission protein B) that mediates membrane fission during the morphological process of spore formation in Bacillus subtilis. Sporulating cells divide asymmetrically, generating a large mother cell and smaller forespore. After division, the mother cell membranes migrate around the forespore in a phagocytic-like process called engulfment. Membrane fission releases the forespore into the mother cell cytoplasm. Cells lacking FisB are severely and specifically impaired in the fission reaction. Moreover, GFP-FisB forms dynamic foci that become immobilized at the site of fission. Purified FisB catalyzes lipid mixing in vitro and is only required in one of the fusing membranes, suggesting that FisB-lipid interactions drive membrane remodeling. Consistent with this idea, the extracytoplasmic domain of FisB binds with remarkable specificity to cardiolipin, a lipid enriched in the engulfing membranes and regions of negative curvature. We propose that membrane topology at the final stage of engulfment and FisB-cardiolipin interactions ensure that the mother cell membranes are severed at the right time and place. The unique properties of FisB set it apart from the known fission machineries in eukaryotes, suggesting that it represents a new class of fission proteins.