Anti-DDX39B antibodies are used in the immunodetection of the protein DExD-box helicase 39B. In humans, the canonical protein has a reported length of 428 amino acid residues and a mass of 49 kDa. Its subcellular localization is in the nucleus and cytoplasm. Alternative splicing is reported to yield 2 different isoforms for this protein. A member of a the DEAD box helicase protein family, DDX39B is known to be involved in nuclear export of spliced and unspliced mRNA. Synonyms for this target antigen include D6S81E, UAP56, spliceosome RNA helicase DDX39B, 56 kDa U2AF65-associated protein, ATP-dependent RNA helicase p47, and BAT1.