Rab39-vesicular transport is usurped by Chlamydia trachomatis to acquire host cell lipids

GAMBARTE J, CAPMANY A , QUINTERO C , GOUD B , DAMIANI MT

Puerto Varas

Congreso; XII PanAmerican Biochemistry and Molecular Biology (PABMB) Meeting; 2013

PABMB-SAIB-Sociedad de Biología de Chile

Chlamydia trachomatis is the causal agent of the most frequent bacterial sexually-transmitted diseases worldwide. This obligate intracellular pathogen exploits different host trafficking pathways to acquire essential molecules for its survival. Rab proteins comprise a family of GTPases that controls eukaryotic cells traffic. The aim of this study was to analyze the participation of Rab39 in the course of chlamydial infection. Rab39a is a poorly characterized protein. We define its localization in multivesicular bodies, late endosomes and a subset of acidic vesicles. By confocal microscopy, we observed that Rab39a associates with the chlamydial inclusion throughout its development. Rab39a colocalizes with two bacterial proteins, IncA and IncG, at the chlamydial inclusion membrane. Overexpression of GFP-Rab39a WT and its positive mutant (GFP-Rab39a Q72L) increases the chlamydial inclusion size. Our results demonstrate that Rab39a decorates vesicles carrying lysobisphosphatidic acid and sphingolipids, and plays a role in the delivery of these molecules from host multivesicular bodies to the chlamydial inclusion. Furthermore, silencing of Rab39a by siRNA reduces bacterial multiplication and infectivity, assessed by the counting of inclusion forming units. Likewise, Rab39a silencing significantly decreases lipid acquisition from infected host cells by these bacteria. These data suggest that Chlamydia trachomatis selectively usurps Rab39a pathway to acquire essential molecules for its development, growth and replication.