Vps32 is required for endocytic trafficking to the lysosome in Trypanosoma brucei

BARRERA, NADIA M.; ALEJANDRA C. SCHOIJET; GUILLERMO D. ALONSO

Modalidad Virtual

Congreso; Molecular parasitology Meeting XXXI; 2020

Trypanosoma brucei alternates between the mammalian bloodstream form (BSF) to multiple stages in the insect vector, including the midgut procyclic form (PCF) requiring processes for adapting and restoring homeostasis during life cycle progression and infection. These processes are guaranteed by membrane trafficking. The multivesicular bodies (MVB) are specialized late endosomes (LE) that function in targeting ubiquitinylated cell surface proteins to thelysosome for degradation and are mainly composed of proteins members of The Endosomal Sorting Complex Required for Transport (ESCRT). ESCRT is composed of four subcomplexes (0-III) being ESCRTIII the most conserved among eukaryotic taxa. Vps32, the most abundant protein of ESCRT III, plays an important role in cytokinesis and vesicular trafficking in Sacharomyces cerevisiae and Homo sapiens. African trypanosomes lack a morphologically well-define MVB, but contain orthologues of the ESCRT, machinery that drives a diverse collection of membrane remodeling events. In fact, in Trypanosoma brucei TbVps23 (ESCRTI) and TbVps4 (the terminal ESCRT ATPase) are both localized to the late endosome and play a role in lysosomal trafficking. Here, we have identified the Vps32 orthologue in Trypanosoma brucei, named TbVps32, associated with endocytic compartments. By the TbVps32 silencing and inducible expression of HA-TbVps32,we addressed the TbVps32 role in vesicular transport to lysosome and cell cycle progression. Knockdown of TbVps32 by interference RNA and HA-TbVps32 inducible over-expression resulted in inhibition of cell growth. Moreover, trafficking of dextran, transferrin and DQ-BSA in endocytic pathway was impaired.Overall, we propose that TbVps32 participates in endocytic trafficking to the lysosome and is essential for Trypanosoma brucei survival.