Lsr-mediated transport and processing of Al-2 in Salmonella typhimurium
Lsr-mediated transport and processing of Al-2 in Salmonella typhimurium
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DOI：
10.1046/j.1365-2958.2003.03781.x
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发表时间：
2003-11-01
影响因子：
3.6
通讯作者：
Bassler, BL
中科院分区：
文献类型：
--
作者：
Taga, ME;Miller, ST;Bassler, BL
LuxS依赖性自诱导物AI-2被认为在细菌的种间细胞间通讯中起作用。在鼠伤寒沙门氏菌中，AI-2在指数生长期间产生并释放，随后通过Lsr（（l）在bar下ux（S）在bar下r）在bar下调节）ATP结合盒（ABC）转运蛋白输入细菌。AI-2诱导lsrACDBFGE操纵子的转录，其中前四个基因编码Lsr转运装置。在这份报告中，我们确定和表征LsrK，一种新的蛋白质，需要的lsr操纵子和AI-2摄取过程的监管。LsrK是一种在进入细胞后磷酸化AI-2的激酶。我们的数据表明，AI-2的磷酸化导致其在细胞质中的隔离。我们认为，磷酸AI-2是诱导剂负责失活的LsrR，阻遏物的LSR操纵子。我们还表明，两个以前未表征的成员的LSR操纵子，LsrF和LsrG，是必要的磷酸AI-2的进一步处理。AI-2的运输和处理可能需要去除群体感应信号，将信号传送到内部检测器和/或清除硼。
The LuxS-dependent autoinducer AI-2 is proposed to function in interspecies cell-cell communication in bacteria. In Salmonella typhimurium, AI-2 is produced and released during exponential growth and is subsequently imported into the bacteria via the Lsr ((l) under bar ux (S) under bar (r) under bar egulated) ATP binding cassette (ABC) transporter. AI-2 induces transcription of the lsrACDBFGE operon, the first four genes of which encode the Lsr transport apparatus. In this report, we identify and characterize LsrK, a new protein that is required for the regulation of the lsr operon and the AI-2 uptake process. LsrK is a kinase that phosphorylates AI-2 upon entry into the cell. Our data indicate that phosphorylation of AI-2 results in its sequestration in the cytoplasm. We suggest that phospho-AI-2 is the inducer responsible for inactivation of LsrR, the repressor of the lsr operon. We also show that two previously uncharacterized members of the lsr operon, LsrF and LsrG, are necessary for the further processing of phospho-AI-2. Transport and processing of AI-2 could be required for removing the quorum-sensing signal, conveying the signal to an internal detector and/or scavenging boron.