Coxiella burnetii modulates Beclin 1 and Bcl-2, preventing host cell apoptosis to generate a persistent bacterial infection.
Coxiella burnetii is the etiological agent of the human disease, Q fever, and is an obligate intracellular bacterium that invades and multiplies in a vacuole with lysosomal characteristics. We have previously shown that Coxiella interacts with the autophagic pathway as a strategy for its survival and replication. In addition, recent studies have shown that Coxiella exerts anti-apoptotic activity to maintain the host cell viability, thus generating a persistent infection. In the present report, we have explored the role of Beclin 1 and Bcl-2 in C. burnetii infection to elucidate how this bacterium modulates autophagy and apoptosis to its own benefit. Beclin 1, a Bcl-2 interacting protein, is required for autophagy. In this study, we show that Beclin 1 is recruited to the Coxiella-membrane vacuole, favoring its development and bacterial replication. In contrast, the anti-apoptotic protein Bcl-2 alters the normal development of the Coxiella-replicative compartment, in spite of also being recruited to the vacuole membrane. Furthermore, both vacuole development and the anti-apoptotic effect of C. burnetii are affected by Beclin 1 depletion and by the expression of a Beclin 1 mutant defective in Bcl-2 binding. Overall, these findings indicate that C. burnetii infection modulates autophagy and apoptotic pathways through Beclin 1/Bcl-2 interplay to establish a successful infection in the host cell.
Vázquez
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CL
Laboratorio de Biología Celular y Molecular- Instituto de Histología y Embriología (IHEM), Facultad de Ciencias Médicas, Universidad Nacional de Cuyo-CONICET, Mendoza, Argentina.
Colombo
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MI
D017209:Apoptosis / Q000502:physiology*; D051017:Apoptosis Regulatory Proteins / Q000235:genetics / Q000378:metabolism*; D001343:Autophagy / Q000502:physiology; D000071186:Beclin-1; D016997:Coxiella burnetii / Q000378:metabolism / Q000472:pathogenicity; D006367:HeLa Cells; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism*; D011778:Q Fever / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014617:Vacuoles / Q000378:metabolism
D051017:Apoptosis Regulatory Proteins; C491997:BECN1 protein, human; D000071186:Beclin-1; C477012:MAP1LC3A protein, human; D008565:Membrane Proteins; D008869:Microtubule-Associated Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D011993:Recombinant Fusion Proteins