There exists two types of tryptophanyl tRNA synthetases, the cytoplasmic form called WARS, the mitochondrial form called WARS2. WARS catalyzes the aminoacylation of tRNA (trp) with tryptophan and is induced by interferon. WARS regulates ERK, Akt, eNOS activation pathway, which are related with angiogenesis, cytoskelatal reorganization and shear stess-reponsive gene expression.