A putative twin-arginine translocation pathway in Legionella pneumophila.
Legionella pneumophila is a facultative intracellular human pathogen causing Legionnaires' disease, a severe form of pneumonia. Because of the importance of secretion pathways in virulence, we were interested in the possible presence of the twin-arginine translocation (Tat) pathway in L. pneumophila. This secretion pathway is used to transport folded proteins, characterized by two arginines in their signal peptide, across the cytoplasmic membrane. We describe here the presence of a putative Tat pathway in L. pneumophila. Three genes encoding Escherichia coli TatA, TatB, and TatC homologues were identified. The tatA and tatB genes were shown to constitute an operon while tatC is monocistronic. RT-PCR analysis revealed expression of the tat genes during both exponential and stationary growth as well as during intracellular growth in Acanthamoeba castellanii. A search for the conserved twin-arginine motif in predicted signal peptides resulted in a list of putative Tat substrates.
De Buck
Emmy
E
Laboratory of Bacteriology, Rega Institute for Medical Research, Katholieke Universiteit Leuven, Minderbroedersstraat 10, B-3000 Leuven, Belgium.
Lebeau
Ilya
I
Maes
Liesbeth
L
Geukens
Nick
N
Meyen
Eef
E
Van Mellaert
Lieve
L
Anné
Jozef
J
Lammertyn
Elke
E
D000595:Amino Acid Sequence; D001665:Binding Sites; D003001:Cloning, Molecular; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D016952:Legionella pneumophila / Q000235:genetics* / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D011485:Protein Binding; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction / Q000502:physiology*; D015533:Transcriptional Activation / Q000502:physiology*
D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; C499697:TatA protein, E coli; C473116:TatB protein, E coli; C461379:TatC protein, E coli; C408585:twin-arginine translocase complex, E coli