Aug 2026· Microbial Pathogenesis· pp.
108762
· 0 citations· 48 references
Medicine
TL;DR
Findings suggest that PGK may function as a moonlighting protein, playing an essential role in the interaction of S. aureus with its host through plasminogen binding.
Abstract
Staphylococcus aureus, a potent opportunistic pathogen causes a variety of infections ranging from mild skin infections to life-threatening diseases. With the rapid increase in antimicrobial resistant pathogens, it is critical to comprehensively understand the virulence strategies employed by the pathogen to invade the host. The glycolytic enzymes of S. aureus have been reported to possess additional roles promoting pathogenesis. In this study, we cloned, overexpressed and purified the S. aureus glycolytic protein, phosphoglycerate kinase (PGK) (EC 2.7.2.3) and investigated its localization and interaction with human plasminogen. To elucidate the localization of PGK, a whole cell ELISA and cell fractionation was performed. We report the localization of the wild type protein in the cytosol as well as the cell surface associated fractions of S. aureus. Whole-cell ELISA with anti-PGK antibodies showed significant antibody binding compared to control with secondary antibody (∼11-fold increase, p = 0.0005), indicating surface exposure of PGK. Purified recombinant PGK bound human plasminogen (p < 0.0001) and enhanced its conversion to its active form in the presence of tissue plasminogen activator (p < 0.0001). Plasminogen binding to PGK was only partially inhibited by ε-aminocaproic acid, indicating that lysine-mediated interactions are not the sole determinants. These results were fully corroborated with the molecular dynamics which revealed stable binding throughout the entire 500ns period and a similar disposition of the lysines. These findings suggest that PGK may function as a moonlighting protein, playing an essential role in the interaction of S. aureus with its host through plasminogen binding.
An extensive insight is provided into the dual role of SpA as a virulence factor in S. aureus pathogenesis and its widespread application in biotechnology, including its vital role in affinity purification of polyclonal and monoclonal antibodies.
Ali N. M. Gubran, Hanan A. A. Mohammed, Runzah Mohsen Saeed et al.· Journal of Proteins and Prot...· 0 citations
It is shown that immunization with PDHC confers robust protection against lethal S. aureus strains, including MRSA, even in previously exposed hosts, as well as protecting against diverse S. aureus strains in multiple murine models.
Jiandong Huang, Xiaolei Wang, Y. Dou et al.· Journal of Immunology· 0 citations
A novel function of Ecb is revealed, the activation of basophils to produce IL-4 in an IgE-independent manner, and a dual Ecb contribution to immune evasion-by interfering with complement activation and skewing Th2 immunity-and a role in the development of allergic inflammation-by inducing IL-4 production is suggested.
Haruka Sakakibara, Shion Kamada, Rikuto Iwata et al.· Microbiology and immunology· 0 citations
Unexpectedly, cytosolic extracts of both WT- and α”SLO-infected macrophages contained all histone proteins, suggesting that nucleosomal complexes are released into the cytosol during GAS infection.
Cheryl Y. M. Okumura, A. Quezada, Kevin Lord et al.· Journal of Immunology· 0 citations
Staphylococcus aureus
(
S. aureus
)is an important foodborne pathogen. Host-derived catecholamines released under stress are known to influence bacterial pathogenic processes, including growth, virulence, biofilm formation. However, the role of dopamine in this context remains less well understood, particularly in
S. aureus
. In this study, we investigated the effects of dopamine on
S. aureus
ATCC 25,923 using a combination of phenotypic assays and multi-omics analyses. Dopamine was taken up by the bacteria and was associated with enhanced pathogenic phenotypes, including increased proliferation, toxin production, biofilm formation, motility, adhesion, and multidrug resistance. In a mouse infection experiment, dopamine treatment further increased bacterial colonization and organ invasion. Mechanistically, multi-omics analyses indicated that dopamine activates the SaeRS two-component system and is associated with the upregulation of virulence-related factors, adhesion-associated proteins, and membrane lipid synthesis pathways, along with increased activity in key metabolic processes such as the tricarboxylic acid (TCA) cycle and oxidative phosphorylation. Importantly, deletion of
saeS
markedly attenuated these dopamine-associated effects. Taken together, these findings suggest that dopamine likely influences
S. aureus
pathogenicity primarily through the SaeRS signaling pathway and provide insight into how host stress signals may contribute to bacterial infection.
Ben Xu, Ziyue Wang, Jinmei Chai et al.· BMC Microbiology· 0 citations
Tuberculosis (TB), caused by Mycobacterium tuberculosis, remains a major global health threat. A key virulence mechanism involves the pathogen’s ability to inhibit apoptosis in infected macrophages, thereby facilitating immune evasion and persistent infection. The pro-apoptotic protein Bcl-2-interacting killer (BIK) represents a critical mediator of macrophage apoptosis. In this study, we engineered a recombinant Mycobacterium smegmatis strain (rMs-BIK) designed to secrete BIK via fusion with the Ag85B signal peptide (ASP). Secretion and expression of the BIK protein were confirmed by Western blotting. Quantitative flow cytometric analysis revealed that rMs-BIK induced significant apoptosis in RAW264.7 macrophages, with rates of 14.49%, 14.22%, and 22.24% at 12, 24, and 48 h post-infection, respectively. These values were markedly higher than those observed in cells infected with the wild-type strain (7.68%, 9.24%, and 10.90%) or the empty vector control (8.80%, 11.19%, and 14.43%). Our findings demonstrate the feasibility of functional pro-apoptotic protein delivery using a mycobacterial vector, providing a robust foundation for the future development of recombinant BCG-based vaccine candidates.
