The interaction of Entamoeba histolytica trophozoites with collagen type I and calcium induces a membrane to nuclei signaling. The transduction pathways involved in such phenomena are still poorly understood. Using a combination of immunoprecipitation assays, Western immunoblot analysis, electrophoretic mobility shift assays and immunocytochemistry we demonstrate here the expression, tyrosine phosphorylation, nuclear translocation and DNA binding of two members of the signal transducers and activators of transcription family of inducible transcription factors in the protozoan parasite E. histolytica. These results support the notion that the interaction of the extracellular matrix components with the parasite turns on a genetic program that facilitates the invasion of the host.

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The Entamoeba histolytica mutant BG-3 has several altered cytoskeletal properties, including the distribution of actin and certain surface characteristics such as osmolarity and electrophoretic mobility. By Western blot analysis and assays for cell adhesion to collagen, we demonstrate that mutant BG-3 shows an increase in the phosphorylation levels of protein kinases that participate in proliferation, adhesion and migration, such as focal adhesion kinase and MAP kinase (Erk2), and that it has also altered its capacity of binding to collagen type I. These results indicate that E. histolytica cytoskeleton integrity plays an important role in adhesion and thus invasion of the host.