MAP3K5 (also known as ASK1) is a serine/threonine kinase that functions as a central hub in cellular stress signaling, particularly under conditions of oxidative stress, endoplasmic reticulum (ER) stress, and inflammatory challenge. MAP3K5 mediates signal transduction by phosphorylating and activating downstream MAP2K proteins (MAP2K3, MAP2K4, MAP2K6, MAP2K7), which subsequently activate p38 MAPK and JNK pathways to control transcription factors like AP-1 [UniProt]. The kinase plays a critical role in apoptosis through mitochondria-dependent caspase activation and is essential for innate immune responses against pathogens [UniProt]. Regulation of MAP3K5 activity occurs through multiple mechanisms: thioredoxin (Trx), tumor necrosis factor receptor-associated factors (TRAFs), 14-3-3 proteins, GSTM2, and TNFAIP3 act as endogenous suppressors by directly binding MAP3K5 and preventing its phosphorylation and activation 123. MAP3K5 demonstrates clinical significance across multiple diseases. In β-thalassemia, MAP3K5 genetic variants predict disease severity and hydroxyurea treatment response 45. MAP3K5 activation contributes to non-alcoholic steatohepatitis progression through JNK/p38 signaling, making ASK1 inhibition a therapeutic target 23. In type 2 diabetes, the ER-stress-responsive MAP3K5 promotes β cell apoptosis, and elevated MAP3K5 expression correlates inversely with β cell abundance 6. Dysregulation of circMAP3K5 contributes to vascular smooth muscle hyperplasia in atherosclerosis and restenosis 7, while MAP3K5 inhibition ameliorates diarrhea-predominant irritable bowel syndrome through suppression of intestinal inflammation 8.