title: Entamoeba histolytica: the over expression of a mutated EhRabB protein produces a decrease of in vitro and in vivo virulence.
abstract: Vesicular trafficking, which is implicated in secretion of cytolytic molecules as well as in phagocytosis, plays an important role in the pathogenic mechanism of Entamoeba histolytica, the protozoan parasite causative of human amoebiasis. Thus, Rab GTPases, that are key regulators of vesicle trafficking, should be considered as molecules involved in the parasite virulence. EhRabB is a Rab protein located in cytoplasmic vesicles that are translocated to phagocytic mouths during ingestion of target cells, suggesting that this Rab protein is involved in phagocytosis. To prove this hypothesis, we over expressed the wild type EhrabB gene and a mutant gene encoding for a protein (RabBN118I) unable to bind guanine nucleotides and therefore constitutively inactive. The over expression of the mutated protein in E. histolytica trophozoites provoked a dominant negative effect, reflected in a significant decrease of both phagocytosis and cytopathic effect as well as in a failure to produce hepatic abscesses in hamsters. These results confirm that EhRabB is involved in phagocytosis and virulence of E. histolytica.
authors.affiliation: Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN, A.P. 14-740, México D.F. 07000, Mexico.
authors.forename: L J
authors.initials: LJ
authors.lastname: Juárez-Hernández
authors.forename: R M
authors.initials: RM
authors.lastname: García-Pérez
authors.forename: A
authors.initials: A
authors.lastname: Salas-Casas
authors.forename: G
authors.initials: G
authors.lastname: García-Rivera
authors.forename: E
authors.initials: E
authors.lastname: Orozco
authors.forename: M A
authors.initials: MA
authors.lastname: Rodríguez
mesh_terms: D000818:Animals; D015153:Blotting, Western; D006224:Cricetinae; D004285:Dogs; D004748:Entamoeba histolytica / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity*; D004912:Erythrocytes / Q000469:parasitology; D005455:Fluorescent Antibody Technique / Q000379:methods; D020558:GTP Phosphohydrolases / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D008101:Liver Abscess, Amebic / Q000469:parasitology; D016296:Mutagenesis; D010587:Phagocytosis / Q000502:physiology; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection; D014774:Virulence
chemical_list: D015800:Protozoan Proteins; D020558:GTP Phosphohydrolases