The α-hydroxyketone LAI-1 regulates motility, Lqs-dependent phosphorylation signalling and gene expression of Legionella pneumophila

Ursula Schell, Sylvia Simon, Tobias Sahr, Dominik Hager, Michael F. Albers, Aline Kessler, Felix Fahrnbauer, Dirk Trauner, Christian Hedberg, Carmen Buchrieser, Hubert Hilbi

Research output: Contribution to journalArticle

Abstract

The causative agent of Legionnaires' disease, Legionella pneumophila, employs the autoinducer compound LAI-1 (3-hydroxypentadecane-4-one) for cell-cell communication. LAI-1 is produced and detected by the Lqs (Legionella quorum sensing) system, comprising the autoinducer synthase LqsA, the sensor kinases LqsS and LqsT, as well as the response regulator LqsR. Lqs-regulated processes include pathogen-host interactions, production of extracellular filaments and natural competence for DNA uptake. Here we show that synthetic LAI-1 promotes the motility of L. pneumophila by signalling through LqsS/LqsT and LqsR. Upon addition of LAI-1, autophosphorylation of LqsS/LqsT by [γ-32P]-ATP was inhibited in a dose-dependent manner. In contrast, the Vibrio cholerae autoinducer CAI-1 (3-hydroxytridecane-4-one) promoted the phosphorylation of LqsS (but not LqsT). LAI-1 did neither affect the stability of phospho-LqsS or phospho-LqsT, nor the dephosphorylation by LqsR. Transcriptome analysis of L. pneumophila treated with LAI-1 revealed that the compound positively regulates a number of genes, including the non-coding RNAsrsmY and rsmZ, and negatively regulates the RNA-binding global regulator crsA. Accordingly, LAI-1 controls the switch from the replicative to the transmissive growth phase of L. pneumophila. In summary, the findings indicate that LAI-1 regulates motility and the biphasic life style of L. pneumophila through LqsS- and LqsT-dependent phosphorylation signalling.

Original languageEnglish (US)
Pages (from-to)778-793
Number of pages16
JournalMolecular Microbiology
Volume99
Issue number4
DOIs
StatePublished - Feb 1 2016

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology

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    Schell, U., Simon, S., Sahr, T., Hager, D., Albers, M. F., Kessler, A., Fahrnbauer, F., Trauner, D., Hedberg, C., Buchrieser, C., & Hilbi, H. (2016). The α-hydroxyketone LAI-1 regulates motility, Lqs-dependent phosphorylation signalling and gene expression of Legionella pneumophila. Molecular Microbiology, 99(4), 778-793. https://doi.org/10.1111/mmi.13265