Cell polarization and adhesion in a motile pathogenic protozoan: role and fate of the Entamoeba histolytica Gal/GalNAc lectin

The human pathogenic protozoan Entamoeba histolytica is a motile cell polar ized into a front pseudopod and a rear uroid. The amoebic Gal/GalNAc surfac e lectin is a major adhesion molecule composed of an immunodominant 170-kDa heavy subunit, mostly extracellular except for a short cytoplasmic tail, a nd of an extracellular light subunit. The binding of multivalent ligands tr iggers lectin capping and recruitment to the uroid. The properties of the G al/GalNAc lectin and its role in amoeba adhesion and uroid polarization are reviewed in the context of the molecular mechanisms underlying cell polari zation and locomotion. (C) 2000 Editions scientifiques et medicales Elsevie r SAS.