title: RNP2 of RNA recognition motif 1 plays a central role in the aberrant modification of TDP-43.
abstract: Phosphorylated and truncated TAR DNA-binding protein-43 (TDP-43) is a major component of ubiquitinated cytoplasmic inclusions in neuronal and glial cells of two TDP-43 proteinopathies, amyotrophic lateral sclerosis and frontotemporal lobar degeneration. Modifications of TDP-43 are thus considered to play an important role in the pathogenesis of TDP-43 proteinopathies. However, both the initial cause of these abnormal modifications and the TDP-43 region responsible for its aggregation remain uncertain. Here we report that the 32 kDa C-terminal fragment of TDP-43, which lacks the RNP2 motif of RNA binding motif 1 (RRM1), formed aggregates in cultured cells, and that similar phenotypes were obtained when the RNP2 motif was either deleted from or mutated in full-length TDP-43. These aggregations were ubiquitinated, phosphorylated and truncated, and sequestered the 25 kDa C-terminal TDP-43 fragment seen in the neurons of TDP-43 proteinopathy patients. In addition, incubation with RNase decreased the solubility of TDP-43 in cell lysates. These findings suggest that the RNP2 motif of RRM1 plays a substantial role in pathological TDP-43 modifications and that it is possible that disruption of RNA binding may underlie the process of TDP-43 aggregation.
authors.affiliation: Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Shinnosuke
authors.initials: S
authors.lastname: Takagi
authors.forename: Yohei
authors.initials: Y
authors.lastname: Iguchi
authors.forename: Masahisa
authors.initials: M
authors.lastname: Katsuno
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Ishigaki
authors.forename: Kensuke
authors.initials: K
authors.lastname: Ikenaka
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Fujioka
authors.forename: Daiyu
authors.initials: D
authors.lastname: Honda
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Niwa
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Tanaka
authors.forename: Hirohisa
authors.initials: H
authors.lastname: Watanabe
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Adachi
authors.forename: Gen
authors.initials: G
authors.lastname: Sobue
mesh_terms: D020816:Amino Acid Motifs; D000818:Animals; D001665:Binding Sites; D002467:Cell Nucleus / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D051379:Mice; D010446:Peptide Fragments / Q000378:metabolism; D010766:Phosphorylation; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D012313:RNA / Q000378:metabolism; D012995:Solubility; D054875:Ubiquitination
chemical_list: D004268:DNA-Binding Proteins; D010446:Peptide Fragments; D012313:RNA