Functional Rewiring of Three Pneumococcal Proteins Into Plasminogen Binders.

To investigate the mechanisms underlying pneumococcal infection, a proteomic analysis was previously conducted to identify pneumococcal proteins in infected mouse samples. In the present study, we characterized three proteins, ATP synthase subunit beta (AtpD), ABC transporter transmembrane protein (Vex3), and fructose bisphosphate aldolase (Fba), which bind to human plasminogen and subsequently facilitate its conversion to plasmin by tissue-type plasminogen activator. These findings suggest that Streptococcus pneumoniae might exploit the proteolytic activity of plasmin to promote infection and highlights the potential importance of plasminogen-binding capacity in the pathogenesis of pneumococcal infection.