title: Characterization of a Rab7-like GTPase, EhRab7: a marker for the early stages of endocytosis in Entamoeba histolytica.
abstract: We have identified a 667 base pair Rab7-like cDNA (EhRab7) from Entamoeba histolytica. The EhRab7 cDNA predicts a polypeptide of at least 206 amino acids with a molecular mass of at least 24.5 kDa. Alignment of EhRab7 with other Rab proteins demonstrated that EhRab7 shared significant homology at the amino acid level with Rab7-like proteins from a number of other eukaryotes, suggesting that EhRab7 is a Rab7 homolog for E. histolytica. Using immunofluorescence microscopy, EhRab7 was demonstrated to be associated with early fluid-phase endosomes (<30 min) and secretory vesicles. The association of EhRab7 with early endosomes disappeared 1 h after their formation. Immunofluorescence microscopy also revealed that this GTPase did not colocalize significantly with phagosomes nor with markers for other organelles including the endoplasmic reticulum, Golgi and late endosomes. These results, together with the known function for Rab7 in other systems, suggest that EhRab7 is bound to vesicles, and that it may participate in vesicle docking and fusion in secretory events, and in the early stages of fluid-phase endocytosis in E. histolytica.
authors.affiliation: Department of Biological Sciences, Clemson University, 132 Long Hall, Clemson, SC 29634, USA.
authors.forename: Brenda H
authors.initials: BH
authors.lastname: Welter
authors.forename: Richard C
authors.initials: RC
authors.lastname: Laughlin
authors.forename: Lesly A
authors.initials: LA
authors.lastname: Temesvari
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015415:Biomarkers; D018076:DNA, Complementary; D004705:Endocytosis; D011992:Endosomes / Q000201:enzymology; D004748:Entamoeba histolytica / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D020558:GTP Phosphohydrolases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D020691:rab GTP-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000090802:rab7 GTP-Binding Proteins
chemical_list: D015415:Biomarkers; D018076:DNA, Complementary; D015800:Protozoan Proteins; D000090802:rab7 GTP-Binding Proteins; D020558:GTP Phosphohydrolases; C464925:Rab7 protein, Entamoeba histolytica; D020691:rab GTP-Binding Proteins