KARS1 antibodies target lysyl-tRNA synthetase (KARS), a ubiquitously expressed enzyme responsible for charging tRNA with the amino acid lysine during protein synthesis. As a member of the aminoacyl-tRNA synthetase (ARS) family, KARS1 plays a critical role in translation fidelity and is essential for cellular viability. It exists in both cytoplasmic and mitochondrial isoforms due to alternative splicing, contributing to distinct functions in cellular and mitochondrial protein synthesis. Dysregulation of KARS1 has been linked to neurological disorders, such as Charcot-Marie-Tooth disease, and mitochondrial defects. Autoantibodies against KARS1 are rare but have been detected in autoimmune conditions like anti-synthetase syndrome, often presenting with interstitial lung disease and myositis. In research, KARS1 antibodies are used to study its role in diseases, protein-RNA interactions, and mitochondrial dysfunction. Recent studies also explore its non-canonical roles in signaling pathways, viral response, and cancer progression, highlighting its therapeutic and diagnostic potential.