A Plasmid-Encoded Phosphatase Regulates Bacillus subtilis Biofilm Architecture, Sporulation, and Genetic Competence
A Plasmid-Encoded Phosphatase Regulates Bacillus subtilis Biofilm Architecture, Sporulation, and Genetic Competence
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DOI：
10.1128/jb.02030-12
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发表时间：
2013-05-01
影响因子：
3.2
通讯作者：
Neiditch, Matthew B.
中科院分区：
文献类型：
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作者：
Parashar, Vijay;Konkol, Melissa A.;Neiditch, Matthew B.
枯草芽孢杆菌生物膜的形成受到复杂信号通路的严格调控。与实验室驯化的B.枯草芽孢杆菌形成光滑的、基本上无特征的菌落，未驯化的菌株如NCIB 3610形成结构复杂的生物膜。NCIB 3610还含有实验室菌株中不存在的80-kb质粒，以及Rap蛋白质RapP的质粒编码同源物中的突变，其引起了高皱纹生物膜表型。在这里，我们探讨了rapP phrP在生物膜形成中的作用。我们发现，RapP是一种磷酸酶，使中间反应调节剂Spo 0 F去磷酸化。RapP似乎采用催化谷氨酸去磷酸化的Spo 0 F乙酰磷酸，和RapP催化谷氨酸的影响进行了讨论。除了调节B。枯草芽孢杆菌生物膜形成，我们发现，RapP调节孢子形成和遗传能力的结果，其能力去磷酸化Spo 0 F。有趣的是，虽然rap phr基因盒通常形成调控对;即，在我们的试验中，成熟phr基因产物抑制rap基因产物的活性，而phrP基因产物不抑制RapP活性。RapP活性，但是，抑制PhrH在体内，但不在体外。另外的遗传分析表明，RapP是直接抑制肽结合。我们推测，PhrH可以在体内进行翻译后修饰，直接抑制RapP活性，或者更有可能的是，PhrH上调肽的表达，反过来，直接结合到RapP，抑制其Spo 0 F磷酸酶活性。
Bacillus subtilis biofilm formation is tightly regulated by elaborate signaling pathways. In contrast to domesticated lab strains of B. subtilis which form smooth, essentially featureless colonies, undomesticated strains such as NCIB 3610 form architecturally complex biofilms. NCIB 3610 also contains an 80-kb plasmid absent from laboratory strains, and mutations in a plasmid-encoded homolog of a Rap protein, RapP, caused a hyperrugose biofilm phenotype. Here we explored the role of rapP phrP in biofilm formation. We found that RapP is a phosphatase that dephosphorylates the intermediate response regulator Spo0F. RapP appears to employ a catalytic glutamate to dephosphorylate the Spo0F aspartyl phosphate, and the implications of the RapP catalytic glutamate are discussed. In addition to regulating B. subtilis biofilm formation, we found that RapP regulates sporulation and genetic competence as a result of its ability to dephosphorylate Spo0F. Interestingly, while rap phr gene cassettes routinely form regulatory pairs; i.e., the mature phr gene product inhibits the activity of the rap gene product, the phrP gene product did not inhibit RapP activity in our assays. RapP activity was, however, inhibited by PhrH in vivo but not in vitro. Additional genetic analysis suggests that RapP is directly inhibited by peptide binding. We speculate that PhrH could be subject to posttranslational modification in vivo and directly inhibit RapP activity or, more likely, PhrH upregulates the expression of a peptide that, in turn, directly binds to RapP and inhibits its Spo0F phosphatase activity.