A two-component system regulates gene expression of the type IX secretion component proteins via an ECF sigma factor.
A two-component system regulates gene expression of the type IX secretion component proteins via an ECF sigma factor.
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DOI：
10.1038/srep23288
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发表时间：
2016-03-21
影响因子：
4.6
通讯作者：
Nakayama K
中科院分区：
文献类型：
--
作者：
Kadowaki T;Yukitake H;Naito M;Sato K;Kikuchi Y;Kondo Y;Shoji M;Nakayama K
牙周病病原体牙龈卟啉单胞菌通过IX型分泌系统（T9 SS）分泌有效的致病性蛋白酶牙龈卟啉菌蛋白酶。该系统包括至少11个组件;然而，其表达的调控机制尚未阐明。在此，我们发现PorY（PGN_2001）-PorX（PGN_1019）-SigP（PGN_0274）级联参与T9 SS的调节。表面等离子体共振（SPR）分析揭示了重组PorY（rPorY）和重组PorX（rPorX）之间的直接相互作用。在Mn ~（2+）存在下，rPorY发生自磷酸化，并将一个磷酰基转移到rPorX上。这些结果表明，PorX和PorY作为一个响应调节剂和组氨酸激酶，分别作为一个双组分系统（TCS），虽然它们是单独编码的染色体上。T9 SS组分编码基因在假定的细胞质外功能（ECF）σ因子PGN_0274（SigP）缺陷的突变体中下调，类似于porX突变体。电泳凝胶位移分析表明，rSigP结合到T9 SS组分编码基因的推定启动子区域。porX突变体中缺少SigP蛋白。免疫共沉淀和SPR分析揭示了SigP和PorX之间的直接相互作用。总之，这些结果表明PorXY TCS通过SigP ECF σ因子调节T9 SS介导的蛋白质分泌。
The periodontopathogen Porphyromonas gingivalis secretes potent pathogenic proteases, gingipains, via the type IX secretion system (T9SS). This system comprises at least 11 components; however, the regulatory mechanism of their expression has not yet been elucidated. Here, we found that the PorY (PGN_2001)-PorX (PGN_1019)-SigP (PGN_0274) cascade is involved in the regulation of T9SS. Surface plasmon resonance (SPR) analysis revealed a direct interaction between a recombinant PorY (rPorY) and a recombinant PorX (rPorX). rPorY autophosphorylated and transferred a phosphoryl group to rPorX in the presence of Mn2+. These results demonstrate that PorX and PorY act as a response regulator and a histidine kinase, respectively, of a two component system (TCS), although they are separately encoded on the chromosome. T9SS component-encoding genes were down-regulated in a mutant deficient in a putative extracytoplasmic function (ECF) sigma factor, PGN_0274 (SigP), similar to the porX mutant. Electrophoretic gel shift assays showed that rSigP bound to the putative promoter regions of T9SS component-encoding genes. The SigP protein was lacking in the porX mutant. Co-immunoprecipitation and SPR analysis revealed the direct interaction between SigP and PorX. Together, these results indicate that the PorXY TCS regulates T9SS-mediated protein secretion via the SigP ECF sigma factor.