Lethal factor of Bacillus anthracis cleaves the N-terminus of MAPKKs: analysis of the intracellular consequences in macrophages.
The lethal toxin of Bacillus anthracis consists of two proteins, PA and LF, which together induce lethal effects in some animal species and cause macrophage lysis. LF is a zinc-binding protein with metalloprotease activity. With a two-hybrid system approach we identified MAP kinase kinases (MAPKKs) Mekl and Mek2 as proteins interacting with LF. LF was shown to cleave Mek1 and Mek2 and an additional MAPKK family member MKK3, within their N-terminal region. We examined macrophage cell lines and primary peritoneal cells with different sensitivities to LF but did not find a direct correlation between MAPKKs cleavage and cell death. On the other hand, sublytic doses of LF cleave MAPKKs and cause a reduction in the LPS/IFNgamma-induced production of proinflammatory mediators. These findings are discussed with respect to the possible role of LF in the initial phase of infection.
Pellizzari
R
R
Centro CNR Biomembrane and Dipartimento di Scienze Biomediche, Università di Padova, Italy.
Guidi-Rontani
C
C
Vitale
G
G
Mock
M
M
Montecucco
C
C
D000818:Animals; D000942:Antigens, Bacterial; D001408:Bacillus anthracis / Q000472:pathogenicity*; D001427:Bacterial Toxins; D002352:Carrier Proteins / Q000633:toxicity*; D002460:Cell Line; D007371:Interferon-gamma / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis; D010766:Phosphorylation; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
D000942:Antigens, Bacterial; D001427:Bacterial Toxins; D002352:Carrier Proteins; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; C030325:anthrax toxin; D009569:Nitric Oxide; D007371:Interferon-gamma; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D020929:Mitogen-Activated Protein Kinase Kinases