Characterization of TcCEST, a novel Trypanosoma cruzi protein associated to the flagellar pocket

DURANTE I; AGÜERO F; A BUSCAGLIA, CARLOS

Mendoza

Congreso; XLVIII Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2012

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB)

The flagellar pocket is a small invagination of the plasma membrane of Trypanosoma cruzi where the flagellum exits the cellular body and is the only site for endo- and exocytosis. Here we characterize a novel T. cruzi protein, termed TcCesT, with homology to bacterial CesT chaperone involved in secretion through the type III system. Also, TcCesT bears a eukaryotic Rad-23 ubiquitin-like domain (UBL) domain, likely involved in receptor mediated endocytosis and nucleotide excision repair (NER). TcCesT is conserved in TriTryps and localizes to the flagellar pocket, as shown by immunocytochemistry and immunoelectron microscopy analysis in wild type and TcCesT overexpressing parasites. Expression data showed that TcCesT is restricted to replicative T. cruzi forms, namely epimastigotes and amastigotes. To further characterize TcCesT, colocalization analyses were performed. TcCesT partially colocalized with both ConA-rhodamine in endocytosis assays and with ubiquitin, suggesting a possible interaction through its UBL domain. A functional NLS, probably involved in regulated nuclear translocation of TcCesT associated to its NER domain, was identified. Finally, TcCesT transfected parasites showed impaired survival under starvation conditions. Taken together, our results suggest that TcCesT may be involved in T. cruzi endo- and exocytosis processes probably required for parasite growth.