The function of MAP3K1 (mitogen-activated protein kinase kinase kinase 1, Ensembl gene identifier ENSG00000095015) is as follows. Component of a protein kinase signal transduction cascade (PubMed:9808624). Activates the ERK and JNK kinase pathways by phosphorylation of MAP2K1 and MAP2K4 (PubMed:9808624). May phosphorylate the MAPK8/JNK1 kinase (PubMed:17761173). Activates CHUK and IKBKB, the central protein kinases of the NF-kappa-B pathway (PubMed:9808624). {ECO:0000269|PubMed:17761173, ECO:0000269|PubMed:9808624}.