THE v-SNARE VAMP7 IS INVOLVED IN THE DEVELOPMENT OF THE C. burnetii REPLICATIVE VACUOLE

CAMPOY, EMANUEL MARTIN; COLOMBO MARIA ISABEL

Congreso; XLVI SAIB; 2010

Coxiella burnetii, the etiological agent of Q fever, is a Gramnegativeobligate intracellular bacterium. It has been previouslydescribed that both the endocytic and autophagic pathwayscontribute to Coxiella replicative vacuoles (CRV) maturation,generating a large parasitophorous niche that shares characteristicof a phagolysosome-autophagolysosomal compartment. We haverecently demonstrated that the early secretory pathway alsocontributes to the Coxiella-vacuole development, since disruptionof this pathway alters vacuole development. VAMP7 is a v-SNAREinvolved in both the secretory and endocytic pathways, whichparticularly participates in the heterotypic fusion between lateendosomes and lysosomes. In the present work, HeLa cellstransiently overexpressing GFP-VAMP7 were infected with C.burnetii for different periods of time. By confocal microscopy, weobserved an interaction between GFP-VAMP7 and C. burnetii atdifferent times after infection. The endogen protein was alsodetected at the CRV. siRNA against VAMP7 and a truncated mutant(VAMP7 NT) were used in order to evaluate the role of this proteinin the CRV development. Our results indicate that both theknockdown of the protein as well as overexpression of the VAMP7truncated mutant affected the development of the Coxiella-vacuolesuggesting that VAMP-7 mediated fusion events are required forthe process.