Characterization of a Rab11 homologue in Trypanosoma cruzi

Vesicle trafficking between organelles occurs through fusion of dormer and specific acceptor membranes. This process is highly regulated and ensures proper direction in sorting and packaging of a number of molecules in eukaryotic cells. Monomeric GTPases of the Rab family play a pivotal role in the control of membrane fusion and vesicle traffic. In this paper, we characterize a Trypanosoma cruzi Rab11 homologue (TcRab11) that shares at, the amino acid level, 40% similarity with human rab11, Arabdopsis thaliana rab11 and yeast rab11 homologue genes. Western blot analysis, using a polyclonal rabbit antiserum raised against a synthetic peptide derived from the COOH-terminus of predicted the TcRab11 protein, reacted to a 26 kDa protein. In immunofluorescence assays, TcRab11, was shown to be expressed in epimastigote and amastigote forms, but it was absent in trypomastigotes. Interestingly, the TcRab11 product seems to be located at the reservosome complex, a site of active endocytosis and Vesicle fusion present only in the epimastigote stage. Therefore, TcRab11 may represent the first molecular marker of this peculiar organelle. (C) 2000 Elsevier Science B.V. All rights reserved.