MAPK3 and cancer: Moreover, consistent with previous report that Mirk/Dyrk1B could be negatively regulated by inhibition of MEK-ERK signaling, in this study western blot analysis also showed that treatment of H292 cells with U0126 for 48 h induced a dose-dependent increase in Mirk/Dyrk1B protein levels (Figure 2C and data not shown), and exposure of H292 cells to 0% FBS for 24 h resulted in up-regulation of Mirk protein levels compared with that to 10% FBS, indicating the increased Mirk possibly mediated by activated ERK1/2 to function cell growth and survival in human cancer.