Rho family proteins are involved in the formation of Coxiella burnetii replicative compartment

AGUILERA M,; ROSALES E,; SALINAS R,; BERÓN W

Rosario, Santa Fe

Congreso; XLII Reunión Nacional de la Sociedad Argentina de Investigaciones Bioquímica y Biología Molecular (SAIB); 2006

Sociedad Argentina de Investigaciones Bioquímica y Biología Molecular (SAIB)

Q fiber is a disease caused by the intracellular pathogen C. burnetii. This bacterium generates a large replicative compartment in the host cell, called parasitophorous vacuole (PV). We have previously observed that actin is involved in the PV formation. It is known that actin dynamics are regulated by Rho family of GTPases. To test if these GTPases play a role in the PV biogenesis, HeLa cells were infected 16 h with C. burnetii and then transfected with pEGFP: Cdc42, RhoA or Rac1 wild types, constitutively active or inactive mutants. C. burnetii was detected by indirect immunofluorescence and the cells were analyzed by confocal microscopy. We observed that PVs were decorated by Cdc42WT and the active V14 but not by the inactive N17 mutants. The number of PVs increased only in cells expressing the active mutant V14. Interestingly, whereas the inactive mutant of RhoA (N19) remained diffuse in the cytoplasm and its expression induced the formation of small vacuoles containing C. burnetii, the active one (RhoAV14) associated with large PVs. In contrast, the formation and the number of PVs were not modified in cells expressing Rac1WT or Rac1 mutants and these proteins were not recruited to the PV membrane. These results suggest that CDC42 and RhoA are involved in PV biogenesis.