Abstract
Introduction: Pragmin is the first mammalian protein that contains a functional the Glu-ProIle-Tyr-Ala (EPIYA) motif. Pragmin is tyrosine-phosphorylated at EPIYA motif by Src family
kinases (SFKs), C-terminal Src kinase (CSK), and in response to epidermal growth factor (EGF)
stimulation. Pragmin can induce some morphological changes in transfected cells characterized
by cell elongation, which can be construed as an invasive phenotype contributing to tumor
invasion and metastasis. This study was established to investigate Src role as a key regulator of
cell motility to induce elongated morphology of cells in Pragmin transfected AGS cells, a human
gastric adenocarcinoma cell line, by using PP2, a specific inhibitor of Src family protein kinase.
Methods: Firstly, AGS cells were transfected with Pragmin and Pragmin mutant (Y391F) using
lipofectamine 2000 reagent and then we treated the cells by PP2. Finally, we evaluated cellmorphological changes in the presence or the absence of PP2 by using light microscopy and the
results were analyzed.
Results: Our results showed in AGS cells that were transiently transfected by Pragmin in the
presence of PP2 (where Src tyrosine kinase activity was inhibited), the number of elongated
cells did not change compared to elongated cell numbers of Pragmin transfected cells in the
absence of PP2.
Conclusion: Our findings suggest that in spite of the importance of Src tyrosine kinase activity
to regulate the cell motility, the cell-morphological changes of Pragmin-transfected AGS cells
is independent of Src activity. It seems that other mechanism(s) to be involved in this process.