LysRS (D16D1) Rabbit mAb #9990

Lysyl-tRNA synthetase (LysRS) is a multifunctional protein that has both regular and mitochondrial forms. The regular form of LysRS belongs to a family of aminoacyl-tRNA synthetases (aaRSs) that catalyze amino acid attachment to its cognate tRNA. In mammalian systems, LysRS forms a multisystem complex (MSC) with several other aaRSs (1-3). In addition to its conventional function, LysRS regulates diadenosine tetraphosphate (Ap4A) production (3). Cellular and metabolic stress increases the level of Ap4A, which functions as a cellular alarm system (3-5). Following FcεRI aggregation in mast cells, MAPK/Erk kinase (MEK) phosphorylates LysRS at Ser207 (5). Serine phosphorylation of LysRS leads to the release of LysRS from MSC and its translocation into the nucleus (5), as well as increased synthesis of Ap4A (5,6). LysRS binds to microphthalmia transcription factor (MITF) and MITF repressor Hint-1. Upon binding of Ap4A, Hint-1 is released from the complex that in turn allows the transcription of MITF-responsive genes (5-7). LysRS is also involved in HIV viral assembly through incorporation into HIV-1 virions via an interaction with HIV-1 Gag (8). Research studies have shown that in the presence of mutant Cu,Zn-superoxide dismutase (SOD1), mitochondrial LysRS tends to be misfolded and degraded by proteasomal degradation, contributing to mitochondrial dysfunction in Amyotrophic Lateral Sclerosis (ALS) (9). LysRS is also secreted and has cytokine-like functions (10). LysRS was also found to be an autoantigen in autoimmune responses (11).