title: Gain-of-function mutational activation of human tRNA synthetase procytokine.
abstract: Disease-causing mutations occur in genes for aminoacyl tRNA synthetases. That some mutations are dominant suggests a gain of function. Native tRNA synthetases, such as tyrosyl-tRNA synthetase (TyrRS) and tryptophanyl-tRNA synthetase, catalyze aminoacylation and are also procytokines that are activated by natural fragmentation. In principle, however, gain-of-function phenotypes could arise from mutational activation of synthetase procytokines. From crystal structure analysis, we hypothesized that a steric block of a critical Glu-Leu-Arg (ELR) motif in full-length TyrRS suppresses the cytokine activity of a natural fragment. To test this hypothesis, we attempted to uncover ELR in the procytokine by mutating a conserved tyrosine (Y341) that tethers ELR. Site-specific proteolytic cleavage and small-angle X-ray scattering established subtle opening of the structure by the mutation. Strikingly, four different assays demonstrated mutational activation of cytokine functions. The results prove the possibilities for constitutive gain-of-function mutations in tRNA synthetases.
authors: Department of Molecular Biology and Chemistry and the Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA. xlyang@scripps.edu
authors: Xiang-Lei
authors: XL
authors: Yang
authors: Mili
authors: M
authors: Kapoor
authors: Francella J
authors: FJ
authors: Otero
authors: Bonnie M
authors: BM
authors: Slike
authors: Hiro
authors: H
authors: Tsuruta
authors: Ricardo
authors: R
authors: Frausto
authors: Alison
authors: A
authors: Bates
authors: Karla L
authors: KL
authors: Ewalt
authors: David A
authors: DA
authors: Cheresh
authors: Paul
authors: P
authors: Schimmel
mesh_terms: D020816:Amino Acid Motifs / Q000235:genetics; D019943:Amino Acid Substitution; D000818:Animals; D002417:Cattle; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002634:Chemotaxis, Leukocyte / Q000187:drug effects; D002642:Chick Embryo; D016207:Cytokines / Q000378:metabolism*; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000187:drug effects; D051379:Mice; D008819:Mice, Nude; D008958:Models, Molecular; D009154:Mutation; D018919:Neovascularization, Physiologic / Q000187:drug effects; D010446:Peptide Fragments / Q000737:chemistry / Q000494:pharmacology; D010447:Peptide Hydrolases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D053838:Scattering, Small Angle; D014448:Tyrosine-tRNA Ligase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014961:X-Ray Diffraction
chemical_list: D016207:Cytokines; D010446:Peptide Fragments; D010447:Peptide Hydrolases; D014448:Tyrosine-tRNA Ligase