Dlk deficiency delays axonal degeneration after sciatic nerve transection and axotomy of dorsal root ganglia.75 Downstream of DLK, pharmacologic inhibition of JNK signaling delays axonal degeneration after axonal injury in drosophila and cultured mammalian neurons.76 Despite the role of MAPK signaling in ocular hypertension-induced axonal degeneration as evidenced by the involvement of DLK and JNK, axonal degeneration after ocular hypertension must proceed through non-canonical DLK signaling because deficiency of its canonical downstream effector, Jun, does not prevent axonal degeneration. The gene discussed is MAPK8; the disease is ocular hypertension.