Regulation of hemolysin expression and virulence of Staphylococcus aureus by a serine/threonine kinase and phosphatase.
Regulation of hemolysin expression and virulence of Staphylococcus aureus by a serine/threonine kinase and phosphatase.
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DOI：
10.1371/journal.pone.0011071
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发表时间：
2010-06-11
期刊：
影响因子：
3.7
通讯作者：
Rajagopal L
中科院分区：
文献类型：
--
作者：
Burnside K;Lembo A;de Los Reyes M;Iliuk A;Binhtran NT;Connelly JE;Lin WJ;Schmidt BZ;Richardson AR;Fang FC;Tao WA;Rajagopal L
外毒素，包括溶血素，即α(α)和β(β)毒素，在金黄色葡萄球菌感染的发病机制中起着重要作用。用随机转座子文库筛选出溶血素表达与野生型相比发生改变的金黄色葡萄球菌突变体。在72个基因中插入转座子，导致溶血素表达增加或减少。失活一个可能的环状二-GMP合成酶和一个丝氨酸/苏氨酸磷酸酶(Stp1)的突变被发现降低了溶血素的表达，而编码一个双组分调节磷酸酶、LysR家族转录调节因子、嘌呤生物合成酶和一个丝氨酸/苏氨酸激酶(Stk1)的基因突变则增加了表达。编码α毒素的HL A基因在Δstp1突变株中转录降低，而在Δstk1株中转录增加。对一个Δstk1突变体的微阵列分析显示，额外的外毒素转录增加。Δstp1株对小鼠的毒力严重减弱，与Δstk1株相比，引起的炎症和IL-6产生较少。体内磷酸肽浓缩和质谱分析表明，ΔSTK1突变体中存在与STK1相应的苏氨酸磷酸化肽、DNA结合组蛋白样蛋白(HU)、富含丝氨酸的纤维蛋白原/骨唾液蛋白结合蛋白(SDRE)和一个假想蛋白(NWMN1123)。综上所述，这些研究表明Stk1介导的Hu、SrdE和NWMN_1123的磷酸化影响金黄色葡萄球菌的基因表达和毒力。
Exotoxins, including the hemolysins known as the alpha (α) and beta (β) toxins, play an important role in the pathogenesis of Staphylococcus aureus infections. A random transposon library was screened for S. aureus mutants exhibiting altered hemolysin expression compared to wild type. Transposon insertions in 72 genes resulting in increased or decreased hemolysin expression were identified. Mutations inactivating a putative cyclic di-GMP synthetase and a serine/threonine phosphatase (Stp1) were found to reduce hemolysin expression, and mutations in genes encoding a two component regulator PhoR, LysR family transcriptional regulator, purine biosynthetic enzymes and a serine/threonine kinase (Stk1) increased expression. Transcription of the hla gene encoding α toxin was decreased in a Δstp1 mutant strain and increased in a Δstk1 strain. Microarray analysis of a Δstk1 mutant revealed increased transcription of additional exotoxins. A Δstp1 strain is severely attenuated for virulence in mice and elicits less inflammation and IL-6 production than the Δstk1 strain. In vivo phosphopeptide enrichment and mass spectrometric analysis revealed that threonine phosphorylated peptides corresponding to Stk1, DNA binding histone like protein (HU), serine-aspartate rich fibrinogen/bone sialoprotein binding protein (SdrE) and a hypothetical protein (NWMN_1123) were present in the wild type and not in the Δstk1 mutant. Collectively, these studies suggest that Stk1 mediated phosphorylation of HU, SrdE and NWMN_1123 affects S. aureus gene expression and virulence.