Anti-methionyl-tRNA synthetase 1 antibodies are used for the immunodetection of the protein encoded by the MARS1 gene. In humans, the canonical protein has a reported length of 900 amino acid residues and a mass of 101.1 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 the Class-I aminoacyl-tRNA synthetase protein family, it is known to catalyze the specific attachment of an amino acid to its cognate tRNA in a 2 step reaction: the amino acid (AA) is first activated by ATP to form AA-AMP and then transferred to the acceptor end of the tRNA. The gene encoding this protein is implicated in Interstitial lung and liver disease. Other names for this target antigen include CMT2U and ILFS2. Gene orthologs have been identified in the mouse, rat, bovine, frog, zebrafish, chimpanzee and chicken species.