title: Parkinson's disease DJ-1 L166P alters rRNA biogenesis by exclusion of TTRAP from the nucleolus and sequestration into cytoplasmic aggregates via TRAF6.
abstract: Mutations in PARK7/DJ-1 gene are associated to autosomal recessive early onset forms of Parkinson's disease (PD). Although large gene deletions have been linked to a loss-of-function phenotype, the pathogenic mechanism of missense mutations is less clear. The L166P mutation causes misfolding of DJ-1 protein and its degradation. L166P protein may also accumulate into insoluble cytoplasmic aggregates with a mechanism facilitated by the E3 ligase TNF receptor associated factor 6 (TRAF6). Upon proteasome impairment L166P activates the JNK/p38 MAPK apoptotic pathway by its interaction with TRAF and TNF Receptor Associated Protein (TTRAP). When proteasome activity is blocked in the presence of wild-type DJ-1, TTRAP forms aggregates that are localized to the cytoplasm or associated to nucleolar cavities, where it is required for a correct rRNA biogenesis. In this study we show that in post-mortem brains of sporadic PD patients TTRAP is associated to the nucleolus and to Lewy Bodies, cytoplasmic aggregates considered the hallmark of the disease. In SH-SY5Y neuroblastoma cells, misfolded mutant DJ-1 L166P alters rRNA biogenesis inhibiting TTRAP localization to the nucleolus and enhancing its recruitment into cytoplasmic aggregates with a mechanism that depends in part on TRAF6 activity. This work suggests that TTRAP plays a role in the molecular mechanisms of both sporadic and familial PD. Furthermore, it unveils the existence of an interplay between cytoplasmic and nucleolar aggregates that impacts rRNA biogenesis and involves TRAF6.
authors.affiliation: SISSA, Sector of Neurobiology, Trieste, Italy.
authors.forename: Sandra
authors.initials: S
authors.lastname: Vilotti
authors.forename: Marta
authors.initials: M
authors.lastname: Codrich
authors.forename: Marco
authors.initials: M
authors.lastname: Dal Ferro
authors.forename: Milena
authors.initials: M
authors.lastname: Pinto
authors.forename: Isidro
authors.initials: I
authors.lastname: Ferrer
authors.forename: Licio
authors.initials: L
authors.lastname: Collavin
authors.forename: Stefano
authors.initials: S
authors.lastname: Gustincich
authors.forename: Silvia
authors.initials: S
authors.lastname: Zucchelli
mesh_terms: D002458:Cell Fractionation; D045744:Cell Line, Tumor; D002466:Cell Nucleolus / Q000235:genetics / Q000378:metabolism*; D049109:Cell Proliferation; D004268:DNA-Binding Proteins; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D016631:Lewy Bodies / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D015513:Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D010300:Parkinson Disease / Q000235:genetics / Q000378:metabolism*; D010727:Phosphoric Diester Hydrolases; D046988:Proteasome Endopeptidase Complex / Q000235:genetics / Q000378:metabolism; D000071617:Protein Deglycase DJ-1; D012335:RNA, Ribosomal / Q000235:genetics / Q000378:metabolism*; D013378:Substantia Nigra / Q000378:metabolism*; D048029:TNF Receptor-Associated Factor 6 / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D015513:Oncogene Proteins; D012335:RNA, Ribosomal; D048029:TNF Receptor-Associated Factor 6; D014157:Transcription Factors; C105131:PARK7 protein, human; D000071617:Protein Deglycase DJ-1; D010727:Phosphoric Diester Hydrolases; C474866:TDP2 protein, human; D046988:Proteasome Endopeptidase Complex