The innate immunity role of cathepsin-D is linked to Trp-491 and Trp-492 residues of listeriolysin O.
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.
Carrasco-Marín
Eugenio
E
Servicio de Inmunología, Hospital Santa Cruz de Liencres y Fundación Marqués de Valdecilla-Instituto de Formación e Investigación Marqués de Valdecilla (IFIMAV), Liencres, Spain. deicme@humv.es
Madrazo-Toca
Fidel
F
de los Toyos
Juan R
JR
Cacho-Alonso
Eva
E
Tobes
Raquel
R
Pareja
Eduardo
E
Paradela
Alberto
A
Albar
Juan Pablo
JP
Chen
Wei
W
Gomez-Lopez
Maria Teresa
MT
Alvarez-Dominguez
Carmen
C
D000818:Animals; D001427:Bacterial Toxins / Q000378:metabolism*; D002402:Cathepsin D / Q000276:immunology*; D002460:Cell Line; D002463:Cell Membrane Permeability; D011992:Endosomes / Q000276:immunology; D005260:Female; D006360:Heat-Shock Proteins / Q000378:metabolism*; D006460:Hemolysin Proteins / Q000378:metabolism*; D007113:Immunity, Innate; D008089:Listeria monocytogenes / Q000235:genetics / Q000276:immunology*; D051379:Mice; D008808:Mice, Inbred CBA; D010588:Phagosomes / Q000276:immunology; D054801:Phosphoinositide Phospholipase C / Q000378:metabolism; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000378:metabolism
D001427:Bacterial Toxins; D006360:Heat-Shock Proteins; D006460:Hemolysin Proteins; D011994:Recombinant Proteins; D054801:Phosphoinositide Phospholipase C; D002402:Cathepsin D; C038705:hlyA protein, Listeria monocytogenes