Entamoeba histolytica: identification of EhGPCR-1, a novel putative G protein-coupled receptor that binds to EhRabB.

EhRabB is an Entamoeba histolytica protein involved in phagocytosis. However, proteins that regulate the EhRabB activity are unknown. Here, we report the identification of a putative G protein-coupled receptor of E. histolytica (EhGPCR-1) that binds to EhRabB. By two-hybrid screening, we found a 372-bp cDNA fragment that encodes the C-terminus of EhGPCR-1. The cloning and sequence of the full-length cDNA revealed that it predicts a polypeptide with two tyrosine-based sorting signals for endocytosis and seven transmembranal domains. These results suggest that EhGPCR-1 could be a GPCR involved in phagocytosis. EhGPCR-1 could be a member of the Rhodopsin family, characterized by a short N-terminus without cysteine residues.