Entamoeba histolytica: Alterations in EhRabB protein in a phagocytosis deficient mutant correlate with the Entamoeba dispar RabB sequence

We analyzed the expression and location of EhRabB in clone L-6, a phagocytosis-deficient mutant of Entamoeba histolytica, in comparison with the wild-type clone A. Intriguingly, trophozoites of clone L-6 express more EhRabB than those of clone A. However, the majority of EhRabB-containing vesicles remained in the cytoplasm of clone L-6 during phagocytosis. To investigate molecular alterations in EhRabB of clone L-6 we compared the EhrabB gene sequences from clones L-6 and A. We also isolated, sequenced and compared the RabB protein of Entamoeba dispar. Results showed that EhrabB gene of clone L-6 is 98.2 and 94.1% identical to rabB genes of E. dispar and clone A, respectively. The rabB genes from clone A and E. dispar have 92.2% identity. Four out of five amino acids changes in RabB proteins of clone L-6 and E. dispar are shared. These changes may alter the binding of effector proteins and the specific subcellular location of EhRabB.