Dual leucine kinase (DLK), a mitogen-activated protein kinase kinase kinase (MAP3K) upstream of JNK/JUN signaling, is also an important regulator of RGC death after axonal injury.55, 71, 72 Furthermore, Dlk has been implicated in axonal degeneration after ocular hypertension injury. The gene discussed is JUN; the disease is ocular hypertension.