innate immunity role of cathepsin-D is linked to Trp-491 and Trp-492 residues of listeriolysin O

• Published in: Molecular microbiology Vol. 72; no. 3; pp. 668 - 682
• Main Authors: Carrasco-Marín, Eugenio, Madrazo-Toca, Fidel, de los Toyos, Juan R, Cacho-Alonso, Eva, Tobes, Raquel, Pareja, Eduardo, Paradela, Alberto, Albar, Juan Pablo, Chen, Wei, Gomez-Lopez, Maria Teresa, Alvarez-Dominguez, Carmen
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01.05.2009; Blackwell Publishing Ltd
• Subjects: Animals; Bacteria; Bacterial proteins; Bacterial Toxins - metabolism; Binding sites; Cathepsin D - immunology; Cell Line; Cell Membrane Permeability; Endosomes - immunology; Female; Heat-Shock Proteins - metabolism; Hemolysin Proteins - metabolism; Immunity, Innate; Listeria monocytogenes; Listeria monocytogenes - genetics; Listeria monocytogenes - immunology; Mice; Mice, Inbred CBA; Microbiology; Mutation; Phagosomes - immunology; Phosphoinositide Phospholipase C - metabolism; Proteases; Protein Structure, Secondary; Recombinant Proteins - metabolism; Studies
• ISSN: 0950-382X; 1365-2958
• DOI: 10.1111/j.1365-2958.2009.06673.x

Listeriolysin O (LLO) is a thiol-activated cytolysin secreted by Listeria monocytogenes. LLO and phosphatidylinositol phospholipase C are two essential virulence factors, which this bacterium needs to escape from the phagosomal compartment to the cytoplasm. Cathepsin-D specifically cleaves LLO, between the Trp-491 (tryptophan amino acid in three letter nomenclature) and Trp-492 residues of the conserved undecapeptide sequence, ECTGLAWEWWR, in the domain 4 of LLO (D4). Moreover, these residues also correspond to the phagosomal-binding epitope. Cathepsin-D had no effect on phosphatidylinositol phospholipase C. We have observed that cathepsin-D cleaved the related cholesterol-dependent cytolysin pneumolysin at the same undecapeptide sequence between Trp-435 and Trp-436 residues. These studies also revealed an additional cathepsin-D cleavage site in the pneumolysin D4 domain localized in the 361-GDLLLD-366 sequence. These differences might confer a pathogenic advantage to listeriolysin O, increasing its resistance to phagosomal cathepsin-D action by reducing the number of cleavages sites in the D4 domain. Using ΔLLO/W491A and ΔLLO/W492A bacterial mutants, we reveal that the Trp-491 residue has an important role linked to cathepsin-D in Listeria innate immunity.