Protein-lysine N-methyltransferase using S-adenosyl-L- methionine as methyl donor (PubMed:22948820, PubMed:32611769). Mono-di and trimethylates 'Lys-943' of AARS1 (PubMed:32611769). . This is the function of ENSG00000139780 (METTL21C, methyltransferase 21C, AARS1 lysine).