Institute for Hygiene and Microbiology, University of Würzburg, Würzburg, Germany.
PLoS One. 2013 Aug 20;8(8):e71644. doi: 10.1371/journal.pone.0071644. eCollection 2013.
The Staphylococcus aureus regulatory saePQRS system controls the expression of numerous virulence factors, including extracellular adherence protein (Eap), which amongst others facilitates invasion of host cells. The saePQRS operon codes for 4 proteins: the histidine kinase SaeS, the response regulator SaeR, the lipoprotein SaeP and the transmembrane protein SaeQ. S. aureus strain Newman has a single amino acid substitution in the transmembrane domain of SaeS (L18P) which results in constitutive kinase activity. SDS was shown to be one of the signals interfering with SaeS activity leading to inhibition of the sae target gene eap in strains with SaeS(L) but causing activation in strains containing SaeS(P). Here, we analyzed the possible involvement of the SaeP protein and saePQ region in SDS-mediated sae/eap expression. We found that SaePQ is not needed for SDS-mediated SaeS signaling. Furthermore, we could show that SaeS activity is closely linked to the expression of Eap and the capacity to invade host cells in a number of clinical isolates. This suggests that SaeS activity might be directly modulated by structurally non-complex environmental signals, as SDS, which possibly altering its kinase/phosphatase activity.
金黄色葡萄球菌的调控 saePQRS 系统控制着许多毒力因子的表达，包括细胞外黏附蛋白（Eap），它可以促进宿主细胞的入侵。saePQRS 操纵子编码 4 种蛋白：组氨酸激酶 SaeS、应答调节蛋白 SaeR、脂蛋白 SaeP 和跨膜蛋白 SaeQ。金黄色葡萄球菌 Newman 株的 SaeS 跨膜结构域（L18P）发生单个氨基酸取代，导致组成型激酶活性。SDS 被证明是干扰 SaeS 活性的信号之一，导致 SaeS(L) 菌株中 sae 靶基因 eap 的抑制，但在含有 SaeS(P) 的菌株中引起激活。在这里，我们分析了 SaeP 蛋白和 saePQ 区在 SDS 介导的 sae/eap 表达中的可能参与。我们发现，SDS 介导的 SaeS 信号不需要 SaePQ。此外，我们可以证明 SaeS 活性与 Eap 的表达和在许多临床分离株中入侵宿主细胞的能力密切相关。这表明 SaeS 活性可能直接受到结构非复杂环境信号的调节，如 SDS，其可能改变其激酶/磷酸酶活性。
