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. Note: This description may include information from UniProtKB.
Protein type: Mitochondrial; Ligase; Translation; EC 188.8.131.52
SS: The number of records in which this modification site was determined using site-specific methods. SS methods include amino acid sequencing, site-directed mutagenesis, modification site-specific antibodies, specific MS strategies, etc.