Lysyl-Trna Synthetase (KARS) Human Recombinant Protein

Aminoacyl-tRNA synthetases are a class of enzymes that charge tRNAs with their cognate amino acids. Lysyl-tRNA synthetase is a homodimer localized to the cytoplasm which belongs to the class II family of tRNA synthetases. It has been shown to be a target of autoantibodies in the human autoimmune diseases, polymyositis or dermatomyositis. Alternatively spliced transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2008]

KARS: Catalyzes the specific attachment of an amino acid to its cognate tRNA in a 2 step reaction: the amino acid (AA) is first activated by ATP to form AA-AMP and then transferred to the acceptor end of the tRNA. When secreted, acts as a signaling molecule that induces immune response through the activation of monocyte/macrophages. Catalyzes the synthesis of diadenosine oligophosphate (Ap4A), a signaling molecule involved in the activation of MITF transcriptional activity. Interacts with HIV-1 virus GAG protein, facilitating the selective packaging of tRNA(3)(Lys), the primer for reverse transcription initiation. Homodimer; also part of a multisubunit complex that groups AIMP1, AIMP2, EEF1A1 and tRNA ligases for Arg, Asp, Glu, Gln, Ile, Leu, Lys, Met and Pro. Interacts with AIMP2 (via N- terminus) and MITF. Interacts directly with HIV-1 virus GAG protein. Up-regulated by DARS and EEF1A1, but not by AIMP2. Belongs to the class-II aminoacyl-tRNA synthetase family. 2 isoforms of the human protein are produced by alternative splicing.

Protein type: EC 6.1.1.6; Translation; Ligase; Mitochondrial

Chromosomal Location of Human Ortholog: 16q23.1

Cellular Component: microtubule cytoskeleton; aminoacyl-tRNA synthetase multienzyme complex; mitochondrion; mitochondrial matrix; cytoplasm; extracellular region; plasma membrane; nucleus; cytosol

Molecular Function: amino acid binding; protein binding; metal ion binding; lysine-tRNA ligase activity; ATP binding; tRNA binding

Biological Process: tRNA aminoacylation for protein translation; lysyl-tRNA aminoacylation; viral reproduction; tRNA processing; gene expression; diadenosine tetraphosphate biosynthetic process

Disease: Deafness, Autosomal Recessive 89; Charcot-marie-tooth Disease, Recessive Intermediate B