Anti-Ephrin A4 antibodies are used in the immunodetection of the protein encoded by the EFNA4 gene. In humans, the canonical protein has a reported length of 201 amino acid residues and a mass of 22.4 kDa. Its subcellular localization is in the cell membrane and is also secreted. Alternative splicing is reported to yield 3 different isoforms for this protein. It is reported to be expressed in the adult spleen, lymph node, prostate, ovary, small intestine, and colon, and in fetal heart, lung, liver and kidney. A member of the Ephrin protein family, it is known to be involved with axon guidance and cell to cell signaling. Post-translational modifications have been described, including glycosylation. Other names for this target antigen include EPLG4, LERK-4, LERK4, eph-related receptor tyrosine kinase ligand 4, ligand of eph-related kinase 4, and EFL4.