Dissecting the mechanisms of tissue transglutaminase-induced cross-linking of α-synuclein: Implications for the pathogenesis of Parkinson disease

Adrien W. Schmid, Diego Chiappe, Vérène Pignat, Valerie Grimminger, Ivan Hang, Marc Moniatte, Hilal A. Lashuel

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31 Citations (Scopus)


Tissue transglutaminase (tTG) has been implicated in the pathogenesis of Parkinson disease (PD). However, exactly how tTG modulates the structural and functional properties of α-synuclein (α-syn) and contributes to the pathogenesis of PD remains unknown. Using site-directed mutagenesis combined with detailed biophysical and mass spectrometry analyses, we sought to identify the exact residues involved in tTG-catalyzed cross-linking of wild-type α-syn and α-syn mutants associated with PD. To better understand the structural consequences of each cross-linking reaction, we determined the effect of tTG-catalyzed cross-linking on the oligomerization, fibrillization, and membrane binding of α-syn in vitro. Our findings show that tTG-catalyzed cross-linking of monomeric α-syn involves multiple cross-links (specifically 2-3). We subjected tTG-catalyzed cross-linked monomeric α-syn composed of either wild-type or Gln → Asn mutants to sequential proteolysis by multiple enzymes and peptide mapping by mass spectrometry. Using this approach, we identified the glutamine and lysine residues involved in tTG-catalyzed intramolecular cross-linking of α-syn. These studies demonstrate for the first time that Gln79 and Gln109 serve as the primary tTG reactive sites. Mutating both residues to asparagine abolishes tTG-catalyzed cross-linking of α-syn and tTG-induced inhibition of α-syn fibrillization in vitro. To further elucidate the sequence and structural basis underlying these effects, we identified the lysine residues that form isopeptide bonds with Gln79 and Gln109. This study provides mechanistic insight into the sequence and structural basis of the inhibitory effects of tTG on α-syn fibrillogenesis in vivo, and it sheds light on the potential role of tTG cross-linking on modulating the physiological and pathogenic properties of α-syn.

Original languageEnglish
Pages (from-to)13128-13142
Number of pages15
JournalJournal of Biological Chemistry
Issue number19
Publication statusPublished - 8 May 2009
Externally publishedYes


ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology
  • Molecular Biology

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