An Entamoeba histolytica Rab-like encoding gene and protein: function and cellular location

We identified here a 576 bp rab-like gene (EhrabB) in Entamoeba histolytica . EhrabB is located 332 bp upstream from the start codon of the Ehcp112 enc oding gene, but is transcribed from the complementary strand. The EhrabB op en reading frame predicts a 192 amino acid polypeptide (EhRabB) with 40-42% identity to Rab proteins, involved in vesicle docking regulation in endo a nd exocytic pathways of eukaryotic cells. Transcripts of 0.6 and 0.97 kb we re detected by the EhrabB probe in northern blot assays. Using specific ant ibodies, EhRabB was located in small cytoplasmic vesicles by confocal micro scopy. During phagocytosis, EhRabB was initially translocated to the plasma membrane and to the phagocytic mouths. The protein diminished after 10 min phagocytosis, suggesting that EhRabB could be participating in the regulat ion of the endocytosis process. (C) 2000 Published by Elsevier Science B.V. All rights reserved.