Outer Membrane Machinery and Alginate Synthesis Regulators Control Membrane Vesicle Production in Pseudomonas aeruginosa
Outer Membrane Machinery and Alginate Synthesis Regulators Control Membrane Vesicle Production in Pseudomonas aeruginosa
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DOI：
10.1128/jb.00722-09
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发表时间：
2009-10
影响因子：
3.2
通讯作者：
Y. Tashiro;Ryosuke Sakai;M. Toyofuku;Isao Sawada;T. Nakajima-Kambe;H. Uchiyama;N. Nomura
中科院分区：
文献类型：
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作者：
Y. Tashiro;Ryosuke Sakai;M. Toyofuku;Isao Sawada;T. Nakajima-Kambe;H. Uchiyama;N. Nomura
人类机会致病菌铜绿假单胞菌在其周围环境中产生膜囊泡。铜绿假单胞菌MV生产机制的几个特征仍然未知。我们先前观察到，在外膜蛋白（OMP）组装中起作用的Opr 86的缺失导致过度囊泡化。在这项研究中，我们发现外膜机制和海藻酸合成调节机制与铜绿假单胞菌的MV生产密切相关。Opr86的缺失导致周质丝氨酸蛋白酶MucD的表达增加，表明周质中错误折叠的OMP的积累与MV的产生有关。事实上，mucD突变体显示出粘液样表型，并且mucD突变引起MV产量增加。具有编码藻酸盐合成调节剂AlgU、MucA或MucB的基因缺失的菌株也引起MV生产的改变。MucD或AlgW丝氨酸蛋白酶的过表达导致MV产生减少，表明位于周质中的蛋白酶抑制铜绿假单胞菌中的MV产生。mucD的缺失导致MV蛋白增加，即使在具有假单胞菌喹诺酮信号（PQS）突变的菌株中也是如此，所述假单胞菌喹诺酮信号（PQS）充当MV产生的正调节剂。这项研究表明，错误折叠的外膜蛋白可能是重要的MV生产，除了PQS，这些监管机构在独立的途径。
ABSTRACT The opportunistic human bacterial pathogen Pseudomonas aeruginosa produces membrane vesicles (MVs) in its surrounding environment. Several features of the P. aeruginosa MV production mechanism are still unknown. We previously observed that depletion of Opr86, which has a role in outer membrane protein (OMP) assembly, resulted in hypervesiculation. In this study, we showed that the outer membrane machinery and alginate synthesis regulatory machinery are closely related to MV production in P. aeruginosa. Depletion of Opr86 resulted in increased expression of the periplasmic serine protease MucD, suggesting that the accumulation of misfolded OMPs in the periplasm is related to MV production. Indeed, the mucD mutant showed a mucoid phenotype and the mucD mutation caused increased MV production. Strains with the gene encoding alginate synthetic regulator AlgU, MucA, or MucB deleted also caused altered MV production. Overexpression of either MucD or AlgW serine proteases resulted in decreased MV production, suggesting that proteases localized in the periplasm repress MV production in P. aeruginosa. Deletion of mucD resulted in increased MV proteins, even in strains with mutations in the Pseudomonas quinolone signal (PQS), which serves as a positive regulator of MV production. This study suggests that misfolded OMPs may be important for MV production, in addition to PQS, and that these regulators act in independent pathways.