Entamoeba histolytica:: Collagen-induced AP-1 DNA binding activity

The interaction of Entamoeba histolytica trophozoites with collagen induces the synthesis and release of electron-dense granules containing a collagenase activity that is an important factor in the pathogenicity of the parasite. The binding is thought to be mediated by an 'integrin-like' collagen receptor. In the signal transduction mechanisms activated by collagen, pp125(FAK) and p42(MAPK) are involved, Using immunoprecipitation assays coupled to Western blot analysis, we demonstrate here the collagen-dependent association of paxillin and Src with pp125(FAK). Furthermore, collagen induces a time-dependent increase in the DNA binding activity of the activator protein 1, which is well correlated with an increase in Fos expression. Our results suggest that a stimulus-transcription coupling triggered by collagen in E. histolytica trophozoites might activate or repress genes involved in tissue invasiveness. (C) 1998 Federation of European Microbiological Societies. Published by Elsevier Science B.V.