Mikrobiologie, Fakultät für Biologie, Universität Freiburg, 79104 Freiburg, Germany.
Proc Natl Acad Sci U S A. 2010 Feb 16;107(7):3163-8. doi: 10.1073/pnas.0911979107. Epub 2010 Jan 28.
We show that translation initiation factor EF-Tu plays a second important role in cell shape maintenance in the bacterium Bacillus subtilis. EF-Tu localizes in a helical pattern underneath the cell membrane and colocalizes with MreB, an actin-like cytoskeletal element setting up rod cell shape. The localization of MreB and of EF-Tu is interdependent, but in contrast to the dynamic MreB filaments, EF-Tu structures are more static and may serve as tracks for MreB filaments. In agreement with this idea, EF-Tu and MreB interact in vivo and in vitro. Lowering of the EF-Tu levels had a minor effect on translation but a strong effect on cell shape and on the localization of MreB, and blocking of the function of EF-Tu in translation did not interfere with the localization of MreB, showing that, directly or indirectly, EF-Tu affects the cytoskeletal MreB structure and thus serves two important functions in a bacterium.
我们发现翻译起始因子 EF-Tu 在枯草芽孢杆菌的细胞形态维持中发挥着第二个重要作用。EF-Tu 在细胞膜下呈螺旋状定位,并与 MreB 共定位,MreB 是一种肌动蛋白样细胞骨架成分,负责形成杆状细胞形态。MreB 和 EF-Tu 的定位是相互依赖的,但与动态的 MreB 纤维不同,EF-Tu 结构更具静态性,可能作为 MreB 纤维的轨道。这一观点与 EF-Tu 和 MreB 在体内和体外相互作用的实验结果一致。降低 EF-Tu 水平对翻译的影响较小,但对细胞形态和 MreB 的定位影响较大,并且阻断 EF-Tu 在翻译中的功能并不干扰 MreB 的定位,这表明 EF-Tu 直接或间接地影响细胞骨架 MreB 结构,因此在细菌中发挥着两个重要功能。