HARS, also known as Histidyl-tRNA synthetase, function to catalyze the aminoacylation of tRNAs by their corresponding amino acids. HARS is from the class II family of aminoacyl-tRNA synthetases. It is responsible for the synthesis of histidyl-transfer RNA, which is essential for the incorporation of histidine into proteins. HARS is a frequent target of autoantibodies in the human autoimmune disease polymyositis/dermatomyositis.