Chlamydia trachomatis recruits Rab39, a novel Golgi-associated GTPase

GAMBARTE J; CAPMANY A; LEIVA N; DAMIANI MT

Potrero de los Funes. San Luis

Congreso; ). XLVII Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2011

SAIB

Chlamydia trachomatis is an obligate intracellular Gram-negative bacterium, which multiplies in a single vacuole called inclusion. This bacterium early dissociates from the endocytic pathway but continues the interaction with the biosynthetic route. This bacterium intercepts vesicles full of nutrients departed from the Golgi apparatus essential for its survival and development. We have described that Chlamydia re-directs Rab11- and Rab14-mediated vesicular transport to capture endogenous lipids synthesized in the Golgi. Rab39 is a recently described host GTPase, localized at the Golgi apparatus, which precise function is still poorly understood. The aim of this study was to investigate if Chlamydia manipulates Rab39-mediated vesicular trafficking for its own nutrition and benefit. Cells overexpressing Rab39a wt and its negative mutant: Rab39a S25N (a GDP-bound inactive form) and its positive mutant: Rab39a Q70L (a GTP-anchored active form) were analyzed by confocal and electron microscopy after bacterial infection. Our results showed that Rab39a wt is recruited to the chlamydial membrane inclusion in a time-dependent fashion. Furthermore, our results demonstrated that Rab39b wt, an isoform of Rab39a wt, did not display the same pattern of recruitment. These results suggest that host Rab39a-mediated transport is subverted by Chlamydia trachomatis to generate a safe intracellular niche where survive and replicate. bacterium, which multiplies in a single vacuole called inclusion. This bacterium early dissociates from the endocytic pathway but continues the interaction with the biosynthetic route. This bacterium intercepts vesicles full of nutrients departed from the Golgi apparatus essential for its survival and development. We have described that Chlamydia re-directs Rab11- and Rab14-mediated vesicular transport to capture endogenous lipids synthesized in the Golgi. Rab39 is a recently described host GTPase, localized at the Golgi apparatus, which precise function is still poorly understood. The aim of this study was to investigate if Chlamydia manipulates Rab39-mediated vesicular trafficking for its own nutrition and benefit. Cells overexpressing Rab39a wt and its negative mutant: Rab39a S25N (a GDP-bound inactive form) and its positive mutant: Rab39a Q70L (a GTP-anchored active form) were analyzed by confocal and electron microscopy after bacterial infection. Our results showed that Rab39a wt is recruited to the chlamydial membrane inclusion in a time-dependent fashion. Furthermore, our results demonstrated that Rab39b wt, an isoform of Rab39a wt, did not display the same pattern of recruitment. These results suggest that host Rab39a-mediated transport is subverted by Chlamydia trachomatis to generate a safe intracellular niche where survive and replicate.