MP1 knockdown inhibits migration in DU145 acutely adherent on fibronectin. A) DU145 cells were transfected with Control (non-targeting) or MP1 siRNA. MP1 depletion inhibits DU145 migration on FN in serum-free medium (SF) by ~50% relative to control. Migration is induced by 1% fetal bovine serum (1%) in cells transfected with control or MP1 siRNA, and the induced component of migration is sensitive to MEK1 inhibition by UO126 (UO). Shown are mean data from three independent experiments; error bars represents S.E.M. B) Representative blot showing MP1 knockdown in DU145 cells treated in parallel with cells in wound-healing assay. Two exposures of MEK1 phospho-SS218/222 are shown to emphasize the low level of MEK1 activation in these assays, which nevertheless remains similar between Control and MP1 siRNA transfected cells. SF, S erum-F ree medium; S, 1% fetal bovine S erum medium; S/U, 1% fetal bovine S erum medium + 25 μM U O126.