Entamoeba histolytica: a beta 1 integrin-like fibronectin receptor assembles a signaling complex similar to those of mammalian cells

During tissue invasion, Entamoeba histolytica trophozoites interact with endothelial cells and extracellular matrix (ECM) proteins such as fibronectin (FN), collagen, and laminin. It has been demonstrated that trophozoites interact with FN through a beta1 integrin-like FN receptor (beta1EhFNR), activating tyrosine kinases. In order to characterize the signaling process triggered by the amoebic receptor, activation, and association of tyrosine kinases and structural proteins were determinated. As a result of FN binding by the beta1EhFNR, the receptor itself, FAK, and paxillin were phosphorylated in tyrosine. Co-immunoprecipitation experiments showed that a multimolecular signaling complex was formed by the amoebic FN receptor, FAK, paxillin, and vinculin. These results strongly suggest that a signaling pathway, similar to the one used in mammalian cells, is activated when E histolytica trophozoites adhere to FN. (C) 2003 Elsevier Science (USA). All rights reserved.