Binding of Cyclic Di-AMP to the Staphylococcus aureus Sensor Kinase KdpD Occurs via the Universal Stress Protein Domain and Downregulates the Expression of the Kdp Potassium Transporter.
Binding of Cyclic Di-AMP to the Staphylococcus aureus Sensor Kinase KdpD Occurs via the Universal Stress Protein Domain and Downregulates the Expression of the Kdp Potassium Transporter.
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DOI：
10.1128/jb.00480-15
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发表时间：
2016-01-01
影响因子：
3.2
通讯作者：
Gründling A
中科院分区：
文献类型：
--
作者：
Moscoso JA;Schramke H;Zhang Y;Tosi T;Dehbi A;Jung K;Gründling A
核苷酸信号分子是重要的细胞内信使，调节广泛的生物学功能。人类病原体金黄色葡萄球菌产生信号核苷酸环二AMP（c-di-AMP）。这种分子在革兰氏阳性菌中很常见，并且在许多生物体中对于在标准实验室生长条件下的生存是必需的。在本研究中，我们研究了c-di-AMP与S. aureus KdpD蛋白。传感激酶KdpD与反应调节因子KdpE形成双组分信号传导系统，并调节kdpDE基因和编码Kdp钾转运蛋白组分的kdpFABC操纵子的表达。在这里，我们表明，S。金黄色葡萄球菌KdpD蛋白通过其通用应激蛋白（USP）结构域特异性地结合c-di-AMP，并具有微摩尔范围内的亲和力。该结构域位于KdpD的N-末端胞质区域内，并且保守的SXS-X20-FTAXY基序的氨基酸对于该结合是重要的。我们进一步表明，KdpD 2，在一些S.金黄色葡萄球菌菌株也结合c-di-AMP，并且我们的生物信息学分析表明，产生c-di-AMP的细菌中的KdpD蛋白的亚类已经进化为结合这种信号传导核苷酸。最后，我们发现c-di-AMP与KdpD的结合抑制了盐胁迫下kdpFABC操纵子的上调，从而表明c-di-AMP是S.金黄色。重要性金黄色葡萄球菌是一种重要的人类病原体，也是西方国家食物中毒的主要原因。保存食物的一种常见方法是使用盐来脱水。这项研究揭示了金黄色葡萄球菌钾吸收的调节，这是这种细菌耐受高水平盐的能力的一个重要方面。我们表明，信号核苷酸C-二-AMP结合到KDP钾摄取系统的调节组分，并且这种结合对编码钾转运蛋白的KDP基因的表达具有抑制作用。c-di-AMP与KdpD的USP结构域结合，从而首次提供了这种结构域结合环状二核苷酸的能力的证据。
Nucleotide signaling molecules are important intracellular messengers that regulate a wide range of biological functions. The human pathogen Staphylococcus aureus produces the signaling nucleotide cyclic di-AMP (c-di-AMP). This molecule is common among Gram-positive bacteria and in many organisms is essential for survival under standard laboratory growth conditions. In this study, we investigated the interaction of c-di-AMP with the S. aureus KdpD protein. The sensor kinase KdpD forms a two-component signaling system with the response regulator KdpE and regulates the expression of the kdpDE genes and the kdpFABC operon coding for the Kdp potassium transporter components. Here we show that the S. aureus KdpD protein binds c-di-AMP specifically and with an affinity in the micromolar range through its universal stress protein (USP) domain. This domain is located within the N-terminal cytoplasmic region of KdpD, and amino acids of a conserved SXS-X20-FTAXY motif are important for this binding. We further show that KdpD2, a second KdpD protein found in some S. aureus strains, also binds c-di-AMP, and our bioinformatics analysis indicates that a subclass of KdpD proteins in c-di-AMP-producing bacteria has evolved to bind this signaling nucleotide. Finally, we show that c-di-AMP binding to KdpD inhibits the upregulation of the kdpFABC operon under salt stress, thus indicating that c-di-AMP is a negative regulator of potassium uptake in S. aureus. IMPORTANCE Staphylococcus aureus is an important human pathogen and a major cause of food poisoning in Western countries. A common method for food preservation is the use of salt to drive dehydration. This study sheds light on the regulation of potassium uptake in Staphylococcus aureus, an important aspect of this bacterium's ability to tolerate high levels of salt. We show that the signaling nucleotide c-di-AMP binds to a regulatory component of the Kdp potassium uptake system and that this binding has an inhibitory effect on the expression of the kdp genes encoding a potassium transporter. c-di-AMP binds to the USP domain of KdpD, thus providing for the first time evidence for the ability of such a domain to bind a cyclic dinucleotide.