title: The surface-displayed chaperones GroEL and DnaK of Mycoplasma pneumoniae interact with human plasminogen and components of the extracellular matrix.
abstract: Mycoplasma pneumoniae is a common cause of community-acquired infections of the human respiratory tract. The strongly reduced genome of the cell wall-less bacteria results in limited metabolic pathways and a small number of known virulence factors. In addition to the well-characterized adhesion apparatus and the expression of tissue-damaging substances, surface-exposed proteins with a primary function in cytosol-located processes such as glycolysis have been attracting attention in recent years. Due to interactions with host factors, it has been suggested that these bacterial proteins contribute to pathogenesis. Here, we investigated the chaperones GroEL and DnaK of M. pneumoniae as candidates for such moonlighting proteins. After successful expression in Escherichia coli and production of polyclonal antisera, the localization of both chaperones on the surface of bacteria was confirmed. Binding of recombinant GroEL and DnaK to human A549 cells, to plasminogen as well as to vitronectin, fibronectin, fibrinogen, lactoferrin and laminin was demonstrated. In the presence of both recombinant proteins and host activators, plasminogen can be activated to the protease plasmin, which is able to degrade vitronectin and fibrinogen. The results of the study extend the spectrum of surface-exposed proteins in M. pneumoniae and indicate an additional role of both chaperones in infection processes.
authors.forename: Lisa
authors.initials: L
authors.lastname: Hagemann
authors.forename: Anne
authors.initials: A
authors.lastname: Gründel
authors.forename: Enno
authors.initials: E
authors.lastname: Jacobs
authors.forename: Roger
authors.initials: R
authors.lastname: Dumke
mesh_terms: D000072283:A549 Cells; D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism*; D015119:Aminocaproic Acid / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D061505:Cell Surface Display Techniques; D018834:Chaperonin 60 / Q000235:genetics / Q000378:metabolism*; D005109:Extracellular Matrix / Q000378:metabolism*; D016326:Extracellular Matrix Proteins / Q000378:metabolism; D006801:Humans; D007106:Immune Sera / Q000276:immunology; D009177:Mycoplasma pneumoniae / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D010958:Plasminogen / Q000378:metabolism*; D011019:Pneumonia, Mycoplasma / Q000378:metabolism / Q000382:microbiology; D011485:Protein Binding; D021381:Protein Transport; D011994:Recombinant Proteins / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D018834:Chaperonin 60; D016326:Extracellular Matrix Proteins; D007106:Immune Sera; D011994:Recombinant Proteins; D010958:Plasminogen; D000251:Adenosine Triphosphatases; D015119:Aminocaproic Acid
keywords: DnaK; GroEL; Mycoplasma pneumoniae; host–pathogen interaction; human extracellular matrix; moonlighting proteins