Identification and characterization of factors affecting cytoskeletal proteins--the mediators of bacterial cell shape

项目摘要 一般来说，通过细胞骨架介导细菌细胞形状的介质还不清楚。我们将探讨 细胞骨架和细胞形状的相互作用基于三个有希望的观察。首先，我们确定了一个 磷脂合酶（CC 1159），当过度表达时，导致细菌新月柄杆菌（Caulobacter crescentus） 改变其形状从新月形到杆状形态通过抑制的定位和功能， 中间丝蛋白称为新月体蛋白。第二，催化失活形式的过表达 磷脂合酶的表达仍然介导细胞形状的变化，这表明表型结果 蛋白质相互作用而不是磷脂水平升高。三、细菌双杂交数据 表明我们的磷脂合酶与自身以及与胞嘧啶三磷酸合酶（CtpS）相互作用， 当通过与新月体蛋白的相互作用过表达时，其也诱导杆状形态。人类 新月体素的同系物，即中间丝核纤层蛋白A/C，与过早衰老有关， 肌营养不良，我们建议之间的联系磷脂合成和中间丝在C。 可能与它们的人类同源物相似。真核生物文献中的研究才刚刚开始 磷脂/鞘脂[和糖基磷脂酰肌醇锚定蛋白（GPI-AP）] 丝，这表明我们的调查在C。crescentus可能与人类有关。此外，本发明还 幽门螺杆菌和霍乱弧菌的新月形有助于宿主定植和发病。 因此，我们的研究结果也可能与这些人类病原体的细胞形状和致病性有关。

PROJECT SUMMARY In general, mediators of bacterial cell shape via the cytoskeleton are not well understood. We will explore the interplay of the cytoskeleton and cell shape based on three promising observations. First, we have identified a phospholipid synthase (CC1159) that, when overexpressed, causes the bacterium Caulobacter crescentus to change its shape from a crescent to a rod-shaped morphology by inhibiting the localization and function of the intermediate filament protein known as crescentin. Second, overexpression of a catalytically inactive version of the phospholipid synthase still mediates the change in cell shape, suggesting that the phenotype results from a protein-protein interaction instead of elevated levels of a phospholipid. Third, bacterial two-hybrid data suggest that our phospholipid synthase interacts with itself and with cytosine triphosphate synthase (CtpS), which also induces a rod-shaped morphology when overexpressed via interaction with crescentin. Human homologs of crescentin, the intermediate filament nuclear Lamins A/C, are implicated in premature aging and muscular dystrophy, and we suggest a link between phospholipid synthesis and intermediate filaments in C. crescentus that may parallel their human homologs. Research in the eukaryotic literature is just starting to link phospholipids/sphingolipids [and glycosylphosphatidylinositol-anchored proteins (GPI-AP)] with intermediate filaments, suggesting that our investigations in C. crescentus may be relevant to humans. Additionally, Helicobacter pylori's and Vibrio cholerae's crescent shape contributes to host colonization and pathogenesis. Thus, our findings may be also relevant to cell shape and pathogenicity of these human pathogens.