Alanyl-tRNA synthetase is a member of the aminoacyl-tRNA synthetase family, key enzymes of protein biosynthesis which charge tRNA molecules with the respective AA. This 108 kDa protein is an autoantigen recognized by PL-12 antibodies which occur in a subset of patients with polymyositis and dermatomyositis. Preliminary data suggest that epitope spreading occurs in the autoimmune PL-12 response such that even antibodies to an isolated alanyl-tRNA molecule can develop Synonyms: Alanyl-tRNA synthetase cytoplasmic, EC 6.1.1.7, Alanine-tRNA ligase, AlaRS, Renal carcinoma antigen NY-REN-42, PL-12, AARS