Laboratoire de Chimie Bactérienne, UPR 9043 Service d'Imagerie Cellulaire, IFR 88, CNRS, Université de la Méditerranée, 31 chemin Joseph Aiguier, 13402 Marseille Cedex 20, France.
Mol Microbiol. 2011 Apr;80(2):309-18. doi: 10.1111/j.1365-2958.2011.07587.x. Epub 2011 Mar 8.
The YvcK protein was previously shown to be dispensable when B. subtilis cells are grown on glycolytic carbon sources but essential for growth and normal shape on gluconeogenic carbon sources. Here, we report that YvcK is localized as a helical-like pattern in the cell. This localization seems independent of the actin-like protein, MreB. A YvcK overproduction restores a normal morphology in an mreB mutant strain when bacteria are grown on PAB medium. Reciprocally, an additional copy of mreB restores a normal growth and morphology in a yvcK mutant strain when bacteria are grown on a gluconeogenic carbon source like gluconate. Furthermore, as already observed for the mreB mutant, the deletion of the gene encoding the penicillin-binding protein PBP1 restores growth and normal shape of a yvcK mutant on gluconeogenic carbon sources. The PBP1 is delocalized in an mreB mutant grown in the absence of magnesium and in a yvcK mutant grown on gluconate medium. Interestingly, its proper localization can be rescued by YvcK overproduction. Therefore, in gluconeogenic growth conditions, YvcK is required for the correct localization of PBP1 and hence for displaying a normal rod shape.
先前的研究表明，YvcK 蛋白在枯草芽孢杆菌利用糖酵解碳源生长时是可有可无的，但在利用糖异生碳源生长和维持正常形态时却是必需的。在这里，我们报告称 YvcK 以螺旋样的模式在细胞中定位。这种定位似乎独立于肌动蛋白样蛋白 MreB。当细菌在 PAB 培养基上生长时，过量表达 YvcK 可以恢复 mreB 突变株的正常形态。相反，当细菌在葡萄糖酸盐等糖异生碳源上生长时，额外的 mreB 拷贝可以恢复 yvcK 突变株的正常生长和形态。此外，与 mreB 突变体一样，青霉素结合蛋白 PBP1 的缺失基因的缺失也可以恢复 yvcK 突变体在糖异生碳源上的生长和正常形态。在没有镁的情况下生长的 mreB 突变体和在葡萄糖酸盐培养基中生长的 yvcK 突变体中，PBP1 发生了定位失调。有趣的是，过量表达 YvcK 可以挽救其正确的定位。因此，在糖异生生长条件下，YvcK 对于 PBP1 的正确定位以及呈现正常的杆状形态是必需的。
