Meier Elizabeth L, Razavi Shiva, Inoue Takanari, Goley Erin D
Department of Biological Chemistry, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, Maryland, 21205, USA.
Department of Biomedical Engineering, Johns Hopkins University School of Medicine, 720 Rutland Avenue, Baltimore, Maryland, 21205, USA.
Mol Microbiol. 2016 Jul;101(2):265-80. doi: 10.1111/mmi.13388. Epub 2016 May 3.
In most bacteria, the tubulin-like GTPase FtsZ forms an annulus at midcell (the Z-ring) which recruits the division machinery and regulates cell wall remodeling. Although both activities require membrane attachment of FtsZ, few membrane anchors have been characterized. FtsA is considered to be the primary membrane tether for FtsZ in bacteria, however in Caulobacter crescentus, FtsA arrives at midcell after stable Z-ring assembly and early FtsZ-directed cell wall synthesis. We hypothesized that additional proteins tether FtsZ to the membrane and demonstrate that in C. crescentus, FzlC is one such membrane anchor. FzlC associates with membranes directly in vivo and in vitro and recruits FtsZ to membranes in vitro. As for most known membrane anchors, the C-terminal peptide of FtsZ is required for its recruitment to membranes by FzlC in vitro and midcell recruitment of FzlC in cells. In vivo, overproduction of FzlC causes cytokinesis defects whereas deletion of fzlC causes synthetic defects with dipM, ftsE and amiC mutants, implicating FzlC in cell wall hydrolysis. Our characterization of FzlC as a novel membrane anchor for FtsZ expands our understanding of FtsZ regulators and establishes a role for membrane-anchored FtsZ in the regulation of cell wall hydrolysis.
在大多数细菌中,微管蛋白样GTP酶FtsZ在细胞中部形成一个环(Z环),该环招募分裂机制并调节细胞壁重塑。尽管这两种活动都需要FtsZ附着于膜,但很少有膜锚定蛋白得到表征。FtsA被认为是细菌中FtsZ的主要膜系链蛋白,然而在新月柄杆菌中,FtsA在稳定的Z环组装和早期FtsZ导向的细胞壁合成之后才到达细胞中部。我们推测还有其他蛋白质将FtsZ系链到膜上,并证明在新月柄杆菌中,FzlC就是这样一种膜锚定蛋白。FzlC在体内和体外都直接与膜结合,并在体外将FtsZ招募到膜上。与大多数已知的膜锚定蛋白一样,FtsZ的C末端肽在体外被FzlC招募到膜以及在细胞中FzlC招募到细胞中部的过程中都是必需的。在体内,FzlC的过量表达会导致胞质分裂缺陷,而fzlC的缺失会导致与dipM、ftsE和amiC突变体产生合成缺陷,这表明FzlC参与细胞壁水解。我们将FzlC表征为FtsZ的一种新型膜锚定蛋白,这扩展了我们对FtsZ调节因子的理解,并确立了膜锚定的FtsZ在调节细胞壁水解中的作用。