The Dif chemosensory pathway is directly involved in phosphatidylethanolamine sensory transduction in Myxococcus xanthus
The Dif chemosensory pathway is directly involved in phosphatidylethanolamine sensory transduction in Myxococcus xanthus
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DOI：
10.1111/j.1365-2958.2005.04785.x
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发表时间：
2005-09-01
影响因子：
3.6
通讯作者：
Shimkets, LJ
中科院分区：
文献类型：
--
作者：
Bonner, PJ;Xu, Q;Shimkets, LJ
黄粘球菌细胞在固体表面上滑动，并受到某些磷脂酰乙醇胺的化学刺激。dif基因簇由6个基因difABCDEG组成，其中5个基因编码与已知趋化蛋白同源的蛋白。DifA和DifE是生物合成原纤维所必需的，原纤维是由多糖和蛋白质组成的细胞外基质。1,2- o-双[11-(Z)-十六烯基]- asn -甘油-3-磷脂酰乙醇胺（16:1 PE）和二脲基PE （12:0 PE）的趋化刺激需要原纤维。虽然先前的研究表明，difA和difE突变体不受12:0 PE的刺激，但这些结果并没有区分对原纤维的依赖或在化学感觉传导中的直接作用。在这里，我们提供了Dif化学感觉通路直接介导PE感觉传导的证据。首先，16:1 PE的刺激和适应需要所有的dif基因，包括difBDG，这对纤维生物发生不是必需的。其次，在DifA的第一个假定甲基化结构域内的特定残基是16:1 PE刺激所必需的，而不是纤维生物发生。通过嵌合的NarX-DifA化学受体的跨膜信号传导是纤维形成所必需的，但不是16:1 PE刺激或适应所必需的。第三，difD和difE是二油基PE （18:1 PE）刺激所必需的，尽管反应不需要原纤维。综上所述，这些结果表明，Dif途径介导基质形成和脂质趋化。
Myxococcus xanthus cells glide on solid surfaces and are chemotactically stimulated by certain phosphatidylethanolamine species. The dif gene cluster consists of six genes, difABCDEG, five of which encode proteins homologous to known chemotaxis proteins. DifA and DifE are required for the biosynthesis of fibrils, an extracellular matrix comprised of polysaccharide and protein. Chemotactic stimulation by 1,2-O-Bis[11-(Z)-hexadecenoyl]-sn-glycero-3-phosphatidylethanolamine (16:1 PE) and dilauroyl PE (12:0 PE) requires fibrils. Although previous work has shown that difA and difE mutants are not stimulated by 12:0 PE, these results do not distinguish between a dependence on fibrils or a direct role in chemosensory transduction. Here we provide evidence that the Dif chemosensory pathway directly mediates PE sensory transduction. First, stimulation by and adaptation to 16:1 PE requires all of the dif genes, including difBDG, which are not essential for fibril biogenesis. Second, a specific residue within the first putative methylation domain of DifA is required for stimulation by 16:1 PE but not fibril biogenesis. Transmembrane signalling through a chimeric NarX-DifA chemoreceptor is required for fibril formation but not for stimulation by or adaptation to 16:1 PE. Third, difD and difE are required for stimulation by dioleoyl PE (18:1 PE) although the response does not require fibrils. Taken together these results argue that the Dif pathway mediates both matrix formation and lipid chemotaxis.