Protein Phosphatase 2A Regulatory Subunit B Promotes MAP Kinase-mediated Migration of A431 Cells

金沢大学大学院医学系研究科保健学専攻Background/Aims: Phosphatases are involved in regulation of MAP kinase (MAPK). A431 cells migrate on collagen after EGF stimulation using MAPK. To clarify the involvement of PP2A in this MAPK-dependent migration, the expression of an isoform of the B regulatory subunit was inhibited. Methods: An antisense sequence corresponding to B cDNA was transfected into A431 cells. Their migratory activity on collagen was examined using Transwell, and MAPK phosphorylation and phosphatase activity were measured, and the results were compared with those obtained with mock-transfected cells. Results: Antisense-transfected cells showed less B protein and phosphatase activity than mock-transfected controls. Migration of antisense-transfected cells showed a low response to EGF. The response of MAPK phosphorylation of antisense-transfected cells to EGF stimulation and adhesion to collagen in the presence or absence of EGF were markedly decreased. Phosphatase activity of PP2A-B also did not respond to EGF, collagen or EGF plus collagen, and remained at low levels. Conclusion: These results suggested that PP2A-B promotes cell migration through the MAPK cascade