title: NMDA receptor stimulation induces temporary alpha-tubulin degradation signaled by nitric oxide-mediated tyrosine nitration in the nervous system of Sepia officinalis.
abstract: Biochemical and immunohistochemical evidence is reported, showing basal protein nitration in specific regions of the optic lobes of Sepia officinalis, mainly in the fiber layers of the plexiform zone. SDS-PAGE analysis of optic lobe extracts revealed an intense 3-nitrotyrosine immunoreactive band identified as alpha-tubulin by immunoprecipitation and partial purification. Stimulation of NMDA receptors resulted in a selective decrease in alpha-tubulin levels within 30 min with partial recovery after 4 h. The effect was suppressed by the NO synthase (NOS) inhibitor L-nitroarginine. Incubation of optic lobes with free 3-nitrotyrosine resulted likewise in a selective loss of alpha-tubulin, due apparently to incorporation of the amino acid into the C-terminus of detyrosinated alpha-tubulin to give the nitrated protein purportedly more susceptible to degradation. Overall, these results point to a novel potential physiologic role of NO and free 3-nitrotyrosine in the control of the alpha-tubulin tyrosination/detyrosination cycle and turnover in Sepia nervous tissue.
authors.affiliation: Zoological Station Anton Dohrn, Villa Comunale, I-80121, Naples, Italy. palumbo@alpha.szn.it
authors.forename: Anna
authors.initials: A
authors.lastname: Palumbo
authors.forename: Gabriella
authors.initials: G
authors.lastname: Fiore
authors.forename: Carlo
authors.initials: C
authors.lastname: Di Cristo
authors.forename: Anna
authors.initials: A
authors.lastname: Di Cosmo
authors.forename: Marco
authors.initials: M
authors.lastname: d'Ischia
mesh_terms: D000818:Animals; D015153:Blotting, Western; D004591:Electrophoresis, Polyacrylamide Gel; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007150:Immunohistochemistry; D008974:Mollusca / Q000166:cytology / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism*; D019335:Nitroarginine / Q000494:pharmacology; D009584:Nitrogen / Q000378:metabolism*; D009899:Optic Lobe, Nonmammalian / Q000378:metabolism; D011233:Precipitin Tests; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism*; D015398:Signal Transduction; D013997:Time Factors; D014404:Tubulin / Q000378:metabolism*; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000378:metabolism*
chemical_list: D004791:Enzyme Inhibitors; D016194:Receptors, N-Methyl-D-Aspartate; D014404:Tubulin; D019335:Nitroarginine; D009569:Nitric Oxide; C002744:3-nitrotyrosine; D014443:Tyrosine; D009584:Nitrogen