While these results suggest that ASK1 may be an ideal candidate for the prevention of ASM cell migration in COPD, the partial inhibition of cell growth may be due to the involvement of other MAPKKKs upstream of JNK and p38 MAPK or due to other signaling events such as ERK1/2 whose role in the regulation of cell proliferation is well known (18, 54). Here, MAPK3 is linked to chronic obstructive pulmonary disease.