IHEM   20887
INSTITUTO DE HISTOLOGIA Y EMBRIOLOGIA DE MENDOZA DR. MARIO H. BURGOS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
The RhoA GTPase and their effectors mDia1 and RHOK are involved in Coxiella burnetii phagocytosis
Autor/es:
SALINAS, R; AGUILERA, M; ROSALES, E; CARMINATI, S; BERON, W
Lugar:
Puerto Madryn
Reunión:
Congreso; XLVI Reunión Nacional de la Sociedad Argentina de Investigaciones Bioquímica y Biología Molecular (SAIB).; 2010
Institución organizadora:
Sociedad Argentina de Investigaciones Bioquímica y Biología Molecular (SAIB)
Resumen:
Phagocytosis is an important defense mechanism against pathogens that is regulated by   actin cytoskeleton. GTPases of Rho family (Cdc42, Rac1 and RhoA) are the mainly regulators of actin cytoskeleton. mDia1 and ROCK kinase are effectors of RhoA that participate in actin dynamics. Coxiella burnetii (Cb) is an intracellular pathogen that induces host actin reorganization during internalization by an unknown molecular mechanism. To analyze if Cb internalization is regulated by Rho GTPases, HeLa cells were transfected with plasmids encoding negative forms of these GTPases and then infected. We observed that negative forms of Rac1 and, in less extent, RhoA inhibited Cb internalization. To assess the participation of mDia1 in bacterial internalization, HeLa cells were infected after transfection with pEGFPmDia1-full length, -ÄN3 (FH1-FH2 domain) or -N1 (GBD domain). We observed that Cb internalization decreased in cell over-expressing the mDia1-N1. This result suggests that actin polymerization activity of mDia1 (FH1-FH2 domain) is important for Cb internalization. To test if ROCK is involved in the internalization, cells were incubated with Y-27632 (ROCK inhibitor) prior infection. The inhibitor diminished the number of Cb internalized what suggests the ROCK participates in this process. These results suggest that Rac1 and RhoA, through ROCK and mDia1 play role in Cb phagocytosis.