Inactivation of the srtA gene in Listeria monocytogenes inhibits anchoring of surface proteins and affects virulence

• Published in: Molecular microbiology 2002-02, Vol.43 (4), p.869-881
• Main Authors: Bierne, Hélène, Mazmanian, Sarkis K., Trost, Matthias, Pucciarelli, M. Graciela, Liu, Gwen, Dehoux, Pierre, Jänsch, Lothar, Portillo, Francisco Garcia‐del, Schneewind, Olaf, Cossart, Pascale
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Aminoacyltransferases - genetics; Aminoacyltransferases - metabolism; Animals; Bacterial Adhesion; Bacterial Outer Membrane Proteins - genetics; Bacterial Outer Membrane Proteins - metabolism; Bacterial Proteins; Cysteine Endopeptidases; Disease Models, Animal; Genes, Bacterial; InlA protein; Life Sciences; Listeria monocytogenes; Listeria monocytogenes - genetics; Listeria monocytogenes - metabolism; Listeria monocytogenes - pathogenicity; Listeriosis - microbiology; Liver - microbiology; Mice; Mice, Inbred BALB C; Microbiology and Parasitology; Molecular Sequence Data; Mutagenesis; Sequence Homology, Amino Acid; sortase; Spleen - microbiology; srtA gene; srtB gene; Staphylococcus aureus - metabolism; Virulence
• ISSN: 0950-382X; 1365-2958
• DOI: 10.1046/j.1365-2958.2002.02798.x

Summary During infection of their hosts, Gram‐positive bac‐teria express surface proteins that serve multiple biological functions. Surface proteins harbouring a C‐terminal sorting signal with an LPXTG motif are covalently linked to the cell wall peptidoglycan by a transamidase named sortase. Two genes encoding putative sortases, termed srtA and srtB, were identified in the genome of the intracellular pathogenic bacterium Listeria monocytogenes. Inactivation of srtA abolishes anchoring of the invasion protein InlA to the bacterial surface. It also prevents the proper sorting of several other peptidoglycan‐associated LPXTG proteins. Three were identified by a mass spectrometry approach. The ΔsrtA mutant strain is defective in entering epithelial cells, similar to a ΔinlA mutant. In contrast to a ΔinlA mutant, the ΔsrtA mutant is impaired for colonization of the liver and spleen after oral inoculation in mice. Thus, L. monocytogenes srtA is required for the cell wall anchoring of InlA and, presumably, for the anchoring of other LPXTG‐containing proteins that are involved in listerial infections.