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Neisseria gonorrhoeae porin modulates phagosome maturation
I M Mosleh1, L A Huber, P Steinlein
1Max-Planck-Institut für Infektionsbiologie, Abteilung Molekulare Biologie, Monbijoustrasse 2, 10117 Berlin, Germany.
Abstract:
The porin (PorB) of Neisseria gonorrhoeae has been implicated in the pathogenesis of this species. Porin is believed to translocate from the bacterial outer membrane into target cell membranes affecting various cell functions. Here we investigated the effect of porin on phagosome maturation. Phagocytosis of latex beads by human macrophages was allowed in the presence or absence of purified porin. Isolation of latex bead-containing phagosomes and subsequent two-dimensional gel electrophoresis revealed substantial differences in the phagosomal protein composition. Immunoblotting detected higher amounts of annexin II and the early endocytic markers Rab5 and transferrin receptor and decreased levels of the late endocytic markers Rab7 and cathepsin D in phagosomes obtained in the presence of porin compared with those obtained in its absence. Furthermore, association of Rab4 with the latex bead-containing phagosomes was revealed by flow cytometry. The amount of this small GTPase was markedly higher in the phagosomes isolated in the presence of porin. The data thus indicate that neisserial porin is itself able to arrest phagosome maturation within macrophages.
Insights
Neisseria gonorrhoeae porin (PorB) was found to arrest phagosome maturation in macrophages. This bacterial protein alters phagosomal pathways, impacting host cell functions during infection.
Area of Science:
- Microbiology
- Cell Biology
- Immunology
Background:
- Neisseria gonorrhoeae porin (PorB) is a key factor in pathogenesis.
- PorB is thought to translocate into host cell membranes, disrupting cellular functions.
Purpose of the Study:
- To investigate the impact of N. gonorrhoeae porin on phagosome maturation.
- To understand the molecular mechanisms by which porin affects phagolysosomal pathways.
Main Methods:
- Human macrophages were incubated with latex beads in the presence or absence of purified N. gonorrhoeae porin.
- Latex bead-containing phagosomes were isolated and analyzed using 2D gel electrophoresis and immunoblotting.
- Flow cytometry was used to detect the association of Rab4 with phagosomes.
Main Results:
- Porin significantly altered the protein composition of phagosomes.
- Early endocytic markers (Rab5, transferrin receptor) and annexin II were increased, while late endocytic markers (Rab7, cathepsin D) were decreased.
- Association of Rab4 with phagosomes was markedly elevated in the presence of porin.
Conclusions:
- Neisserial porin directly inhibits phagosome maturation in macrophages.
- PorB disrupts normal phagolysosomal trafficking, potentially contributing to N. gonorrhoeae pathogenesis.