Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.
EMBO J. 2010 Jan 20;29(2):315-26. doi: 10.1038/emboj.2009.356. Epub 2009 Dec 3.
Gliding motility in the bacterium Myxococcus xanthus uses two motility engines: S-motility powered by type-IV pili and A-motility powered by uncharacterized motor proteins and focal adhesion complexes. In this paper, we identified MreB, an actin-like protein, and MglA, a small GTPase of the Ras superfamily, as essential for both motility systems. A22, an inhibitor of MreB cytoskeleton assembly, reversibly inhibited S- and A-motility, causing rapid dispersal of S- and A-motility protein clusters, FrzS and AglZ. This suggests that the MreB cytoskeleton is involved in directing the positioning of these proteins. We also found that a DeltamglA motility mutant showed defective localization of AglZ and FrzS clusters. Interestingly, MglA-YFP localization mimicked both FrzS and AglZ patterns and was perturbed by A22 treatment, consistent with results indicating that both MglA and MreB bind to motility complexes. We propose that MglA and the MreB cytoskeleton act together in a pathway to localize motility proteins such as AglZ and FrzS to assemble the A-motility machineries. Interestingly, M. xanthus motility systems, like eukaryotic systems, use an actin-like protein and a small GTPase spatial regulator.
在粘细菌 Myxococcus xanthus 中，滑行运动使用两种运动引擎：由 IV 型菌毛驱动的 S 运动和由未鉴定的运动蛋白和焦点黏附复合物驱动的 A 运动。在本文中，我们确定了肌动蛋白样蛋白 MreB 和 Ras 超家族的小 GTPase MglA 对于这两种运动系统都是必需的。MreB 细胞骨架组装抑制剂 A22 可逆地抑制 S-和 A-运动，导致 S-和 A-运动蛋白簇 FrzS 和 AglZ 的快速分散。这表明 MreB 细胞骨架参与指导这些蛋白质的定位。我们还发现，DeltamglA 运动突变体显示 AglZ 和 FrzS 簇的定位缺陷。有趣的是，MglA-YFP 定位模拟了 FrzS 和 AglZ 的模式，并受到 A22 处理的干扰，这与表明 MglA 和 MreB 都结合到运动复合物的结果一致。我们提出 MglA 和 MreB 细胞骨架一起作用于一个途径，将运动蛋白（如 AglZ 和 FrzS）定位到组装 A 运动机器中。有趣的是，像真核生物系统一样，粘细菌的运动系统使用肌动蛋白样蛋白和小 GTPase 空间调节剂。
