evaluation of cell- morphological changes by helicobacter pylori caga and pragmin in ags human gastric carcinoma cells

background: helicobacter pylori caga oncoprotein was injected into mammalian host cells via type iv secretion system, where it was tyrosine phosphorylated at the glu-pro-ile-tyr-ala (epiya) sequence. tyrosine phosphorylation of caga was shown to be a prerequisite for the induction of actin cytoskeletal rearrangement in ags gastric epithelial cells. the needle-like projections, known as the hummingbird phenotype, are thought to be involved in gastric disease. moreover, pragmin, a mammalian protein, contains a single epiya motif, and tyrosine phosphorylation of pragmin at epiya motif in ags cells induce cell-morphological changes, which are characterized by elongated cell shape with invasive phenotype that contributes to tumor invasion and metastasis. methods: in this study, ags cells were transfected by caga or/and pragmin using lipofectamine 2000 reagent, then, cellmorphological changes were investigated using light microscope. finally, elongated cells were counted and the results were compared. results: our results revealed that there is a competition between caga and pragmin to interact with csk via epiya motif. we also found that although the cell-morphological changes are particularly dependent on tyrosine phosphorylation at epiya motifs in both, changes of cell morphology are different in caga and pragmin transfected cells. conclusions: our findings suggest that the mechanisms inducing the elongated cell morphology in caga or pragmin transfected cells may be different.