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Peroxynitrite affects exocytosis and SNARE complex formation and induces tyrosine nitration of synaptic proteins
Author(s) -
Di Stasi A. M. Michela,
Mallozzi Cinzia,
Macchia Gianfranco,
Maura Guido,
Petrucci Tamara C.,
Minetti Maurizio
Publication year - 2002
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.2002.00980.x
Subject(s) - peroxynitrite , exocytosis , chemistry , superoxide , nitric oxide , synaptic vesicle , biochemistry , microbiology and biotechnology , vesicle fusion , munc 18 , snap25 , peroxynitrous acid , biophysics , vesicle , biology , secretion , membrane , organic chemistry , enzyme
The reactive species peroxynitrite, formed via the near diffusion‐limited reaction of nitric oxide and superoxide anion, is a potent oxidant that contributes to tissue damage in neurodegenerative disorders. Peroxynitrite readily nitrates tyrosine residues in proteins, producing a permanent modification that can be immunologically detected. We have previously demonstrated that in the nerve terminal, nitrotyrosine immunoreactivity is primarily associated with synaptophysin. Here we identify two other presynaptic proteins nitrated by peroxynitrite, Munc‐18 and SNAP25, both of which are involved in sequential steps leading to vesicle exocytosis. To investigate whether peroxynitrite affects vesicle exocytosis, we used the fluorescent dye FM1‐43 to label a recycling population of secretory vesicles within the synaptosomes. Bolus addition of peroxynitrite stimulated exocytosis and glutamate release. Notably, these effects were strongly reduced in the presence of NaHCO 3 , indicating that peroxynitrite acts mainly intracellularly. Furthermore, peroxynitrite enhanced the formation of the sodium dodecyl sulfate‐resistant SNARE complex in a dose‐dependent manner (100–1000 µ m ) and induced the formation of 3‐nitrotyrosine in proteins of SNARE complex. These data suggest that modification(s) of synaptic vesicle proteins induced by peroxynitrite may affect protein–protein interactions in the docking/fusion steps, thus promoting exocytosis, and that, under excessive production of superoxide and nitric oxide, neurons may up‐regulate neuronal signaling.