Lsr-mediated transport and processing of AI-2 in Salmonella typhimurium.

TitleLsr-mediated transport and processing of AI-2 in Salmonella typhimurium.
Publication TypeJournal Article
Year of Publication2003
AuthorsTaga, ME, Miller, ST, Bassler, BL
JournalMol Microbiol
Volume50
Issue4
Pagination1411-27
Date Published2003 Nov
ISSN0950-382X
KeywordsATP-Binding Cassette Transporters, Bacterial Proteins, Biological Transport, Epistasis, Genetic, Gene Expression Regulation, Bacterial, Homoserine, Lactones, Operon, Phenotype, Phosphorylation, Protein Kinases, Salmonella typhimurium
Abstract

<p>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 (luxS regulated) 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.</p>

DOI10.1046/j.1365-2958.2003.03781.x
Alternate JournalMol. Microbiol.
PubMed ID14622426
Grant ListR01 G65859 / / PHS HHS / United States