Intracellular levels and activity of PvdS, the major iron starvation sigma factor of Pseudomonas aeruginosa
Intracellular levels and activity of PvdS, the major iron starvation sigma factor of Pseudomonas aeruginosa
复制标题
PvdS 的细胞内水平和活性，PvdS 是铜绿假单胞菌的主要铁饥饿西格玛因子
作者：
F. Tiburzi;F. Imperi;P. Visca
在铜绿假单胞菌中，铁饥饿sigma因子PvdS指导铁限制下pyoverdine和毒力基因的转录。PvdS活性由pyoverdine通过涉及FpvA受体和内膜跨越传感器FpvR的表面信号级联调节。为了深入了解PvdS与主要sigma RpoD竞争RNA聚合酶（RNAP）结合的分子机制，我们测定了P. aeruginosa PAO1细胞内RNAP、RpoD和PvdS的水平，以及pyoverdine信号传导对PvdS活性的影响。在铁限制下，铜绿假单胞菌每个细胞分别含有2221个和933个RNAP分子和RpoD分子。PvdS达到62%的RpoD水平。高PvdS含量部分被30%的PvdS保留在膜上所抵消，将细胞质PvdS的浓度降低到RpoD水平的45%。从缺铁的铜绿假单胞菌细胞中纯化RNAP表明，与RpoD-RNAP相比，PvdS-RNAP的代表性较差（分别占RNAP总量的1%和27%）。Pyoverdine信号不影响PvdS的细胞含量，但促进PvdS从膜上释放，使其细胞质浓度从pvdF和fpvA信号突变体的35%增加到野生型的70%和fpvR突变体的83%。
In Pseudomonas aeruginosa the iron starvation sigma factor PvdS directs the transcription of pyoverdine and virulence genes under iron limitation. PvdS activity is modulated by pyoverdine through the surface signalling cascade involving the FpvA receptor and the inner membrane‐spanning sensor FpvR. To gain insight into the molecular mechanisms enabling PvdS to compete with the major sigma RpoD for RNA polymerase (RNAP) binding, we determined the intracellular levels of RNAP, RpoD and PvdS in P. aeruginosa PAO1, and the effect of pyoverdine signalling on PvdS activity. Under iron limitation, P. aeruginosa contains 2221 and 933 molecules of RNAP and RpoD per cell respectively. PvdS attains 62% of RpoD levels. The high PvdS content is partly offset by retention of 30% of PvdS on the membrane, lowering the concentration of cytosolic PvdS to 45% of RpoD levels. RNAP purification from iron‐starved P. aeruginosa cells demonstrated that PvdS–RNAP is poorly represented compared with RpoD–RNAP (1 and 27% of total RNAP respectively). Pyoverdine signalling does not affect the PvdS cellular content but facilitates PvdS release from the membrane, increasing its cytosolic concentration from 35% in both pvdF and fpvA signalling mutants to 70% in the wild type and 83% in the fpvR mutant.
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DOI：
10.1073/pnas.0600828103
发表时间：
2006-04-04
影响因子：
11.1
作者：
Grigorova, IL;Phleger, NJ;Gross, CA
通讯作者：
Gross, CA
影响因子：
--
作者：
J. Helmann
通讯作者：
J. Helmann
铜绿假单胞菌的氧和铁依赖性σ因子pvdS是实验性感染性心内膜炎的重要毒力因子。
DOI：
10.1086/315338
发表时间：
2000
期刊：
The Journal of infectious diseases.
影响因子：
--
作者：
Xiong,YQ;Vasil,ML;Johnson,Z;Ochsner,UA;Bayer,AS
通讯作者：
Bayer,AS
DOI：
10.1073/pnas.0504266102
发表时间：
2005-08-02
影响因子：
11.1
作者：
Banin, E;Vasil, ML;Greenberg, EP
通讯作者：
Greenberg, EP
DOI：
10.1073/pnas.91.16.7573
发表时间：
1994-08-02
影响因子：
11.1
作者：
LONETTO, MA;BROWN, KL;BUTTNER, MJ
通讯作者：
BUTTNER, MJ