Fig. 6. Inhibition of ERK1/2 signalling enhances ERK5 activation by Src. NIH3T3 cells were transfected with expression vectors for Y527F Src, dominant-negative MEK1 (MEK1A), dominant-negative MEK5 (MEK5AA) or ERK5 (ERK5AEF), where indicated, cells were treated with 1 µM PD184352