Downregulation of Src Family Kinase Activity Using PP2 Inhibitor Has No Effect on the Elongation of Pragmin-Transfected Adenocarcinoma AGS cells

Pragmin is the first mammalian protein that contains a functional the Glu-Pro-Ile-Tyr-Ala (EPIYA) motif. Pragmin was tyrosine phosphorylation by Src family kinases (SFKs), in response to epidermal growth factor (EGF) stimulation, and C-terminal Src kinase (CSK) at EPIYA motif. Pragmin transfected cells induced cell-morphological changes which were characterized by elongated cell shape with invasive phenotype that contributes 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 cells by using PP2, a specific inhibitor of Src family protein kinase.
Firstly, AGS cells were transfected by Pragmin and Pragmin mutant (Y391F) using lipofectamine 2000 reagent and then we treated the cells by PP2. Finally, we evaluated cell-morphological changes in the presence or the absence of PP2 by using light microscope and the results were analyzed.
Our results showed in AGS cells that were transiently transfected by Pragmin in the presence of PP2 (where Src activity was reduced), number of elongated cells were not changed compared to elongated cell numbers of Pragmin transfected cells in the absence of PP2.
Our findings suggest that in spite of importance of Src to regulate the cell motility, cell-morphological changes of AGS transfected cells by Pragmin is independent on Src activity and it seems the other mechanism (s) are involved in these process.