Histidyl-tRNA Synthetase (HARS) Human Recombinant Protein

Aminoacyl-tRNA synthetases are a class of enzymes that charge tRNAs with their cognate amino acids. The protein encoded by this gene is a cytoplasmic enzyme which belongs to the class II family of aminoacyl-tRNA synthetases. The enzyme is responsible for the synthesis of histidyl-transfer RNA, which is essential for the incorporation of histidine into proteins. The gene is located in a head-to-head orientation with HARSL on chromosome five, where the homologous genes share a bidirectional promoter. The gene product is a frequent target of autoantibodies in the human autoimmune disease polymyositis/dermatomyositis. Several transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Apr 2012]

HARS: Defects in HARS are a cause of Usher syndrome type 3B (USH3B). USH3B is a syndrome characterized by progressive vision and hearing loss during early childhood. Some patients have the so-called 'Charles Bonnet syndrome,' involving decreased visual acuity and vivid visual hallucinations. USH is a genetically heterogeneous condition characterized by the association of retinitis pigmentosa with sensorineural deafness. Age at onset and differences in auditory and vestibular function distinguish Usher syndrome type 1 (USH1), Usher syndrome type 2 (USH2) and Usher syndrome type 3 (USH3). USH3 is characterized by postlingual, progressive hearing loss, variable vestibular dysfunction, and onset of retinitis pigmentosa symptoms, including nyctalopia, constriction of the visual fields, and loss of central visual acuity, usually by the second decade of life. Belongs to the class-II aminoacyl-tRNA synthetase family.

Protein type: Translation; EC 6.1.1.21; Ligase

Chromosomal Location of Human Ortholog: 5q31.3

Cellular Component: cytoplasm; cytosol

Molecular Function: histidine-tRNA ligase activity; ATP binding

Biological Process: tRNA aminoacylation for protein translation; translation; gene expression; histidyl-tRNA aminoacylation

Disease: Usher Syndrome, Type Iiib