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Identification of Putative Substrates of the Legionella pneumophila Tat Secretion Pathway via Two-Dimensional Protein Gel Electrophoresis, Page 1 of 2
< Previous page Next page > /docserver/preview/fulltext/10.1128/9781555815660/9781555813901_Chap54-1.gif /docserver/preview/fulltext/10.1128/9781555815660/9781555813901_Chap54-2.gifAbstract:
Different secretion pathways have been shown to play a role in the virulence of Legionella pneumophila. Recently the authors showed the presence of the twin-arginine translocation (Tat) pathway in L. pneumophila Philadelphia-1 and its importance in intracellular replication and biofilm formation. The Tat pathway translocates folded proteins across the cytoplasmic membrane. In order to study the importance of the Tat pathway in the virulence of L. pneumophila, the identification of Tat substrates and their possible involvement in virulence was initiated. Since some Tat substrates might be transported across the outer membrane following Tat-dependent transport across the cytoplasmic membrane, the authors looked for differential spots in culture media of the wild-type strain and two Tat secretion mutants (tatB and tatC mutant) by two-dimensional protein gel electrophoresis analysis. Three proteins were found to be absent from the culture medium of the Tat secretion mutants: LvrE, Lpg1962 (a peptidyl-prolyl cis-trans isomerase), and Lpg2320 (a hypothetical protein). The lvrE gene is situated in between the lvh (Legionella vir homologues) genes on the L. pneumophila Philadelphia-1 genome that encode the Lvh type IV secretion system. Based on two-dimensional analysis, three proteins were found to be absent in the culture media of the L. pneumophila tatB and tatC mutant. For one of these proteins, LvrE, Tat dependence was confirmed using specific antibodies.