MAP3K3/MEKK3

MAP3K3 (MEKK3) signals predominantly through the MEK5-ERK5 module while also feeding the MKK3/6-p38 and MKK4/7-JNK cascades, positioning it as a hub of the STE11 group. MEKK3 is required for vascular integrity and placental development, and knockout embryos die in mid-gestation with defective angiogenesis and hemorrhage. It responds to TNF, lysophosphatidic acid, and osmotic and oxidative stress, and cooperates with 14-3-3 proteins and PB1-domain-containing partners for signal assembly. In immunity, MEKK3 governs B- and T-cell homeostasis and NF-κB activation downstream of antigen receptors. Amplification or dysregulation of MAP3K3 occurs in several cancers, and it is studied in hypertension and tumor angiogenesis.