Ramamurthi Kumaran S, Losick Richard
Department of Molecular and Cellular Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA 02138, USA.
Proc Natl Acad Sci U S A. 2009 Aug 11;106(32):13541-5. doi: 10.1073/pnas.0906851106. Epub 2009 Jul 28.
Bacterial proteins often localize to distinct sites within the cell, but the primary cues that dictate localization are largely unknown. Recent evidence has shown that positive membrane curvature can serve as a cue for localization of a peripheral membrane protein. Here we report that localization of the peripheral membrane protein DivIVA is determined in whole or in part by recognition of negative membrane curvature and that regions of the protein near the N and C terminus are important for localization. DivIVA, which is a cell division protein in Bacillus subtilis, localizes principally as a ring at nascent septa and secondarily to the less negatively curved, inside surface of the hemispherical poles of the cell. When cytokinesis is prevented, DivIVA redistributes itself to, and becomes markedly enriched at, the poles. When the rod-shaped cells are converted into spheres (protoplasts) by treatment with lysozyme, DivIVA adopts a largely uniform distribution around the cell. Recognition of membrane curvature by peripheral membrane proteins could be a general strategy for protein localization in bacteria.
细菌蛋白常常定位于细胞内不同的位点,但决定其定位的主要线索在很大程度上尚不清楚。最近的证据表明,正的膜曲率可作为外周膜蛋白定位的一个线索。在此我们报告,外周膜蛋白DivIVA的定位全部或部分由对负膜曲率的识别所决定,并且该蛋白靠近N端和C端的区域对定位很重要。DivIVA是枯草芽孢杆菌中的一种细胞分裂蛋白,主要定位于新生隔膜处形成一个环,其次定位于细胞半球形极的负曲率较小的内表面。当胞质分裂被阻止时,DivIVA会重新分布到细胞极并在那里显著富集。当用溶菌酶处理将杆状细胞转化为球形(原生质体)时,DivIVA在细胞周围呈现大致均匀的分布。外周膜蛋白对膜曲率的识别可能是细菌中蛋白定位的一种普遍策略。