title: Identification of novel bacterial plasminogen-binding proteins in the human pathogen Mycobacterium tuberculosis.
abstract: Binding and activation of human plasminogen (Plg) to generate the proteolytic enzyme plasmin (Plm) have been associated with the invasive potential of certain bacteria. In this work, proteomic analysis together with ligand blotting assays identified several major Plg-binding spots in Mycobacterium tuberculosis soluble extracts (SEs) and culture filtrate proteins. The identity of 15 different proteins was deduced by N-terminal and/or MS and corresponded to DnaK, GroES, GlnA1, Ag85 complex, Mpt51, Mpt64, PrcB, MetK, SahH, Lpd, Icl, Fba, and EF-Tu. Binding of Plg to recombinant M. tuberculosis DnaK, GlnA1, and Ag85B was further confirmed by ELISA and ligand blotting assays. The binding was inhibited by epsilon-aminocaproic acid, indicating that the interaction involved lysine residues. Plg bound to recombinant mycobacterial proteins was activated to Plm by tissue-type Plg activator. In contrast with recombinant proteins, M. tuberculosis SE enhanced several times the Plg activation mediated by the activator. Interestingly, GlnA1 was able to bind the extracellular matrix (ECM) protein fibronectin. Together these results show that M. tuberculosis posses several Plg receptors suggesting that bound Plg to bacteria surface, can be activated to Plm, endowing bacteria with the ability to break down ECM and basal membranes proteins contributing to tissue injury in tuberculosis.
authors.affiliation: Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México, D.F., México.
authors.forename: Wendy
authors.initials: W
authors.lastname: Xolalpa
authors.forename: Antonio J
authors.initials: AJ
authors.lastname: Vallecillo
authors.forename: Martha
authors.initials: M
authors.lastname: Lara
authors.forename: Guillermo
authors.initials: G
authors.lastname: Mendoza-Hernandez
authors.forename: Marcelo
authors.initials: M
authors.lastname: Comini
authors.forename: Ralf
authors.initials: R
authors.lastname: Spallek
authors.forename: Mahavir
authors.initials: M
authors.lastname: Singh
authors.forename: Clara
authors.initials: C
authors.lastname: Espitia
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D001483:Base Sequence; D015153:Blotting, Western; D002853:Chromatography, Liquid; D017931:DNA Primers; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D008024:Ligands; D009169:Mycobacterium tuberculosis / Q000378:metabolism*; D010958:Plasminogen / Q000378:metabolism*; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D001426:Bacterial Proteins; D017931:DNA Primers; D008024:Ligands; D010958:Plasminogen