Anti-MAP3K3 antibodies are used in the immunodetection of the protein mitogen-activated protein kinase kinase kinase 3. In humans, the canonical protein has a reported length of 626 amino acid residues and a mass of 70.9 kDa. Alternative splicing is reported to yield 2 different isoforms for this protein. A member of a the STE Ser/Thr protein kinase protein family, MAP3K3 is a known component of the protein kinase signal transduction cascade. Post-translational modifications have been described, including phosphorylation. Synonyms for this target antigen include MEKK3, MAP/ERK kinase kinase 3, MAPK/ERK kinase kinase 3, MEK kinase 3, MEKK 3, and MAPKKK3.