The temperature-sensing protein TlpA is repressed by PhoP and dispensable for virulence of Salmonella enterica serovar Typhimurium in mice
The temperature-sensing protein TlpA is repressed by PhoP and dispensable for virulence of Salmonella enterica serovar Typhimurium in mice
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DOI：
10.1016/j.micinf.2006.04.015
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发表时间：
2006-07-01
影响因子：
5.8
通讯作者：
Finlay, B. Brett
中科院分区：
文献类型：
--
作者：
Gal-Mor, Ohad;Valdez, Yanet;Finlay, B. Brett
TlpA是一种温度敏感的卷曲螺旋蛋白，编码于沙门氏菌鼠伤寒血清型的peptide毒力质粒。以前认为TlpA在沙门氏菌的致病性中起作用。在这里，我们表明，TIpA是严格调节，差异表达的环境和生理信号的反应，并可以在体外分泌。发现在含有限制浓度的Mg 2+的改良基本培养基中和在生长的稳定期中抑制tlpA的表达，但在丰富的LB肉汤中诱导并响应于升高的温度。发现反应调节剂PhoP与另外两个调节剂RpoS和TlpA本身一起在tlpA的抑制中起关键作用。此外，我们还证明了TlpA对S.宿主细胞内的鼠伤寒沙门氏菌和小鼠毒力。根据提出的同源性TlpA的IncP质粒编码的蛋白质，KfrA，SMC家族成员，TlpA的潜在功能进行了讨论。累积起来，我们的数据不支持以前的假设，即TlpA本身的沙门氏菌的致病性中发挥作用，但可能表明TlpA的替代功能无关的宿主感染。(c)2006年爱思唯尔SAS。All rights reserved.
TlpA is a temperature-sensing, coiled-coil protein, encoded on the pSLT virulence plasmid of Salmonella enterica serovar Typhimurium. TlpA was previously presumed to play a role in the pathogenicity of Salmonella. Herein we show that TIpA is tightly regulated, differentially expressed in response to environmental and physiological signals, and can be secreted in vitro. Expression of tlpA was found to be repressed in modified minimal medium containing limiting concentrations of Mg2+ and in the stationary phase of growth, but induced in rich LB broth and in response to elevated temperatures. The response regulator PhoP was found to play a key role in the repression of tlpA in conjunction with two other regulators, RpoS and TlpA itself. In addition, we demonstrate that TlpA is dispensable for intracellular proliferation of S. Typhimurium within host cells and for virulence in mice. Based on presented homology of TlpA to the IncP plasmid encoded protein, KfrA, and to SMC family members, a potential function for TlpA is discussed. Cumulatively, our data do not support the previous hypothesis that TlpA plays a role in the pathogenicity of Salmonella per se, but may suggest an alternative function for TlpA unrelated to host infection. (c) 2006 Elsevier SAS. All rights reserved.