title: Structural analysis of disease-related TDP-43 D169G mutation: linking enhanced stability and caspase cleavage efficiency to protein accumulation.
abstract: The RNA-binding protein TDP-43 forms intracellular inclusions in amyotrophic lateral sclerosis (ALS). While TDP-43 mutations have been identified in ALS patients, how these mutations are linked to ALS remains unclear. Here we examined the biophysical properties of six ALS-linked TDP-43 mutants and found that one of the mutants, D169G, had higher thermal stability than wild-type TDP-43 and that it was cleaved by caspase 3 more efficiently, producing increased levels of the C-terminal 35 kD fragments (TDP-35) in vitro and in neuroblastoma cells. The crystal structure of the TDP-43 RRM1 domain containing the D169G mutation in complex with DNA along with molecular dynamics simulations reveal that the D169G mutation induces a local conformational change in a β turn and increases the hydrophobic interactions in the RRM1 core, thus enhancing the thermal stability of the RRM1 domain. Our results provide the first crystal structure of TDP-43 containing a disease-linked D169G mutation and a disease-related mechanism showing that D169G mutant is more susceptible to proteolytic cleavage by caspase 3 into the pathogenic C-terminal 35-kD fragments due to its increased stability in the RRM1 domain. Modulation of TDP-43 stability and caspase cleavage efficiency could present an avenue for prevention and treatment of TDP-43-linked neurodegeneration.
authors.affiliation: Institute of Molecular Biology, Academia Sinica, Taipei, 11529, Taiwan.|Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsin Chu, 30013, Taiwan.
authors.forename: Chien-Hao
authors.initials: CH
authors.lastname: Chiang
authors.affiliation: Institute of Biomedical Sciences, Academia Sinica, Taipei, 11529, Taiwan.
authors.forename: Cédric
authors.initials: C
authors.lastname: Grauffel
authors.affiliation: Institute of Molecular Biology, Academia Sinica, Taipei, 11529, Taiwan.
authors.forename: Lien-Szu
authors.initials: LS
authors.lastname: Wu
authors.affiliation: Institute of Molecular Biology, Academia Sinica, Taipei, 11529, Taiwan.
authors.forename: Pan-Hsien
authors.initials: PH
authors.lastname: Kuo
authors.affiliation: Institute of Molecular Biology, Academia Sinica, Taipei, 11529, Taiwan.
authors.forename: Lyudmila G
authors.initials: LG
authors.lastname: Doudeva
authors.affiliation: Institute of Biomedical Sciences, Academia Sinica, Taipei, 11529, Taiwan.
authors.forename: Carmay
authors.initials: C
authors.lastname: Lim
authors.affiliation: Institute of Molecular Biology, Academia Sinica, Taipei, 11529, Taiwan.
authors.forename: Che-Kun James
authors.initials: CK
authors.lastname: Shen
authors.affiliation: Institute of Molecular Biology, Academia Sinica, Taipei, 11529, Taiwan.
authors.forename: Hanna S
authors.initials: HS
authors.lastname: Yuan
mesh_terms: D019943:Amino Acid Substitution; D020169:Caspases / Q000378:metabolism; D003062:Codon; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D009154:Mutation; D011487:Protein Conformation; D011489:Protein Denaturation; D055550:Protein Stability; D059748:Proteolysis; D013816:Thermodynamics
chemical_list: D003062:Codon; D004268:DNA-Binding Proteins; C000598624:TARDBP protein, human; D004247:DNA; D020169:Caspases