Forms part of a macromolecular complex that catalyzes the attachment of specific amino acids to cognate tRNAs during protein synthesis. Modulates the secretion of AIMP1 and may be involved in generation of the inflammatory cytokine EMAP2 from AIMP1. ATP + L-arginine + tRNA(Arg) = AMP + diphosphate + L-arginyl-tRNA(Arg) Interacts (via N-terminus) with AIMP1 (via N-terminus); this stimulates its catalytic activity. Interacts (via N-terminus) with LARS2 (via C-terminus). Monomer. Part of a multisubunit complex that groups tRNA ligases for Arg (RARS1), Asp (DARS1), Gln (QARS1), Ile (IARS1), Leu (LARS1), Lys (KARS1), Met (MARS1) the bifunctional ligase for Glu and Pro (EPRS1) and the auxiliary subunits AIMP1/p43, AIMP2/p38 and EEF1E1/p18. Interacts with QARS1. Part of a complex composed of RARS1, QARS1 and AIMP1. The alpha-helical N-terminus (residues 1-72) mediates interaction with AIMP1 and thereby contributes to the assembly of the multisynthetase complex. The alternative initiation site Met-74 is uncertain. Belongs to the class-I aminoacyl-tRNA synthetase family.