| Phenotype |
ERK1 | Viable; possible prolonged neuronal synapse |
ERK2 | Lethal D11; failure of placental development; ERK2 knockdown fibroblasts do not proliferate in vitro |
ERK5 | Lethal D10; endothelial cell failure and vascular leakage in conditional knockout |
JNK1 | Viable; defect in Th1 differentiation; reduced osteoclastogenesis; sensitivity to induced dermal tumorigenesis; insulin resistance |
JNK2 | Viable; defect in Th1 differentiation; reduced arthritic joint destruction; resistance to induced dermal tumorigenesis |
JNK1+JNK2 | Lethal D16; failure in late-stage brain/CNS development; fibroblasts show reduced proliferation in vitro; resistant to physical-stress-induced apoptosis; defective TNF-α-induced AP-1 activation |
JNK3 | Viable; resistant to stress-induced neuronal apoptosis |
p38α | Lethal D11; defect in angiogenesis |
| Cells resistant to apoptosis induced by Fas; increased transformation in presence of activated Ras; defect in MAPKAPK-2 activation and TNF-α, IL-1 and IL-6 expression |
p38β | Viable; no defects observed in the immune responses studied |
p38γ | Not reported |
p38δ | Not reported |