Apoptotic activity and sub-cellular localization of a T4SS-associated CagE-homologue in Actinobacillus actinomycetemcomitans.
A potent virulence factor, cagE homologue of Actinobacillus actinomycetemcomitans, was identified via an expression cloning strategy and periodontitis-associated CD4(+)T-cells of a humanized mouse model. Through the immuno-gold labeling with transmission electron microscopy, immunofluorescent staining, in vitro co-cultures and Western blot studies, the resulting data clearly demonstrate that: (i) in CagE-homologue treated human epithelia in vitro, there are ultra-structural features of plasma membrane blebbing, sub-cellular disorganization with condensed and marginalized chromatins along the nuclear membrane, consistent with the pro-apoptotic characteristics, (ii) the disturbed membrane integrity detected above is associated with localization of the CagE proteins on target cell surface, and (iii) CagE-homologue is located in the cytoplasm of A. actinomycetemcomitans and associated with a bacterial type-IV secretion system (T4SS), suggesting that its translocation is required for secretion. Thus, CagE-homologue may be critically involved in A. actinomycetemcomitans-induced tissue destruction, inflammation and subsequent adverse immunity in periodontal pathogenesis.
Teng
Yen-Tung A
YT
School of Medicine and Dentistry, University of Rochester Medical Centre, 625 Elmwood Ave. Rochester, NY, 14620-2989, USA.
Zhang
Xiaoxia
X
D016976:Aggregatibacter actinomycetemcomitans / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity* / Q000648:ultrastructure; D000818:Animals; D017209:Apoptosis; D001426:Bacterial Proteins / Q000378:metabolism / Q000633:toxicity; D002462:Cell Membrane / Q000378:metabolism / Q000648:ultrastructure; D002478:Cells, Cultured; D018920:Coculture Techniques; D003593:Cytoplasm / Q000378:metabolism; D004847:Epithelial Cells / Q000378:metabolism / Q000382:microbiology* / Q000648:ultrastructure; D006801:Humans; D007624:KB Cells; D051379:Mice; D008822:Mice, Transgenic; D021381:Protein Transport; D037521:Virulence Factors / Q000378:metabolism* / Q000633:toxicity*
D001426:Bacterial Proteins; D037521:Virulence Factors