title: Protein tyrosine nitration is triggered by nerve growth factor during neuronal differentiation of PC12 cells.
abstract: Nitric oxide (NO) is a signaling molecule implicated in a spectrum of cellular processes including neuronal differentiation. The signaling pathway triggered by NO in physiological processes involves the activation of soluble guanylate cyclase and S-nitrosylation of proteins, and, as recently proposed, nitration of tyrosine residues in proteins. However, little is known about the mechanisms involved and the target proteins for endogenous NO during the progression of neuronal differentiation. To address this question, we investigated the presence, localization, and subcellular distribution of nitrated proteins during neurotrophin-induced differentiation of PC12 cells. We find that some proteins show basal levels of tyrosine nitration in PC12 cells grown in the absence of nerve growth factor (NGF) and that nitration levels increase significantly after 2 days of incubation with this neurotrophin. Nitrated proteins accumulate over a period of several days in the presence of NGF. We demonstrate that this nitration is coupled to activation of nitric oxide synthase. The subcellular distribution of nitrated proteins changes during PC12 cell differentiation, displaying a shift from the cytosolic to the cytoskeletal fraction and we identified alpha-tubulin as the major target of nitration in PC12 cells by N-terminal sequence and MALDI-TOF analyses. We conclude that tyrosine nitration of proteins could be a novel molecular mechanism involved in the signaling pathway by which NO modulates NGF-induced differentiation in PC12 cells.
authors.affiliation: Department of Biology, University of Milan, Via Celoria 26, 20133 Milan, Italy. graziella.cappelletti@unimi.it
authors.forename: Graziella
authors.initials: G
authors.lastname: Cappelletti
authors.forename: Maria G
authors.initials: MG
authors.lastname: Maggioni
authors.forename: Gabriella
authors.initials: G
authors.lastname: Tedeschi
authors.forename: Rosalba
authors.initials: R
authors.lastname: Maci
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D020932:Nerve Growth Factor / Q000502:physiology*; D009474:Neurons / Q000166:cytology* / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D016716:PC12 Cells; D011499:Protein Processing, Post-Translational / Q000502:physiology*; D011506:Proteins / Q000378:metabolism; D051381:Rats; D015398:Signal Transduction; D014404:Tubulin / Q000032:analysis / Q000378:metabolism; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000032:analysis / Q000378:metabolism*
chemical_list: D004791:Enzyme Inhibitors; D011506:Proteins; D014404:Tubulin; D009569:Nitric Oxide; C002744:3-nitrotyrosine; D014443:Tyrosine; D020932:Nerve Growth Factor; D019001:Nitric Oxide Synthase