Downstream from the MAP-Kinase is located the JNK patways with C-JUN as main member. 
This pathway is usually stimulated by stress whether the stress is radiation or a Tumor Necrosis factor.
Antibody to C-jun arrest the cell cycle at G1 to S phase.  Speculation is this how DNA alteration, which is perceived as a stress by the cell, though this pathway, activate P53 and induce cell cycle arrest.  This pathways seems to participate in tissue differentiation.  Formation of the brain is particularly compromised by mutations at C-jun (most likely located at Chromosome One).  C-jun may regulate few promoter gene expression and interact with Cyclin D1.  C-jun is to be tested for mutation in cancer naturally responsive to growth factors and interleukins  (And response to Radiation therapy).  We are digging deeper to clarify some of these assumptions!