ENTAMOEBA-HISTOLYTICA - COLLAGEN-INDUCED AP-1 DNA-BINDING ACTIVITY

The interaction of Entamoeba histolytica trophozoites with collagen in duces the synthesis and release of electron-dense granules containing a collagenase activity that is an important factor in the pathogenicit y of the parasite. The binding is thought to be mediated by an 'integr in-like' collagen receptor. In the signal transduction mechanisms acti vated by collagen, pp125(FAK) and p42(MAPK) are involved, Using immuno precipitation 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 correla ted with an increase in Fos expression. Our results suggest that a sti mulus-transcription coupling triggered by collagen in E. histolytica t rophozoites might activate or repress genes involved in tissue invasiv eness. (C) 1998 Federation of European Microbiological Societies. Publ ished by Elsevier Science B.V.