MAP3K5/ASK1

MAP3K5, universally known as ASK1 (apoptosis signal-regulating kinase 1), is a central STE11-group MAP3K of oxidative and endoplasmic reticulum stress signaling. In resting cells ASK1 is held inactive by reduced thioredoxin bound to its N-terminal region; ROS-dependent oxidation releases this brake, permitting oligomerization with TRAF2 and autophosphorylation. Active ASK1 phosphorylates MKK4/7 and MKK3/6, driving sustained JNK and p38 activation that culminates in apoptosis. ASK1 contributes to neurodegeneration, cardiac hypertrophy, diabetes and inflammatory diseases, and its inhibitor selonsertib reached late-stage clinical trials in NASH, making ASK1 a flagship drug target among MAP3Ks.