| Title: | Binding Specificity of Native Odorant-Binding Protein Isoforms Is Driven by Phosphorylation and O-N-Acetylglucosaminylation in the Pig Sus scrofa |
| Author(s): | Nagnan-Le Meillour P; Joly A; Le Danvic C; Marie A; Zirah S; Cornard JP; |
| Address: | "Unite de Glycobiologie Structurale et Fonctionnelle, UMR8576, USC-UGSF INRA 1409, CNRS-Universite de Lille, Lille, France. ALLICE R&D, Paris, France. Unite Molecules de Communication et Adaptation des Microorganismes, Museum National d'Histoire Naturelle, UMR 7245 CNRS/MNHN, Paris, France. Laboratoire de Spectroscopie Infrarouge et Raman, UMR8516 CNRS-Universite de Lille, Lille, France" |
| Journal Title: | Front Endocrinol (Lausanne) |
| ISSN/ISBN: | 1664-2392 (Print) 1664-2392 (Electronic) 1664-2392 (Linking) |
| Abstract: | "Odorant-binding proteins (OBP) are secreted in the nasal mucus at the vicinity of olfactory receptors (ORs). They act, at least, as an interface between hydrophobic and volatile odorant molecules and the hydrophilic medium bathing the ORs. They have also been hypothesized to be part of the molecular coding of odors and pheromones, by forming specific complexes with odorant molecules that could ultimately stimulate ORs to trigger the olfactory transduction cascade. In a previous study, we have evidenced that pig olfactory secretome was composed of numerous olfactory binding protein isoforms, generated by O-GlcNAcylation and phosphorylation. In addition, we have shown that recombinant OBP (stricto sensu) produced in yeast is made up of a mixture of isoforms that differ in their phosphorylation pattern, which in turn determines binding specificity. Taking advantage of the high amount of OBP secreted by a single animal, we performed a similar study, under exactly the same experimental conditions, on native isoforms isolated from pig, Sus scrofa, nasal tissue. Four fractions were obtained by using strong anion exchange HPLC. Mapping of phosphorylation and O-GlcNAcylation sites by CID-nanoLC-MS/MS allowed unambiguous localization of phosphosites at S13 and T122 and HexNAc sites at S13 and S19. T112 or T115 could also be phosphorylated. BEMAD analysis suggested extra phosphosites located at S23, S24, S41, S49, S57, S67, and T71. Due to the very low stoichiometry of GlcNAc-peptides and phosphopeptides, these sites were identified on total mixture of OBP isoforms instead of HPLC-purified OBP isoforms. Nevertheless, binding properties of native OBP isoforms to specific ligands in S. scrofa were monitored by fluorescence spectroscopy. Recombinant phosphorylated OBP-Pichia isoforms bind steroids and fatty acids with slight differences. Native isoforms, that are phosphorylated but also O-GlcNAcylated show radically different binding affinities for the same compounds, which strongly suggests that O-GlcNAcylation increases the binding specificity of OBP isoforms. These findings extend the role of O-GlcNAc in regulating the function of proteins involved in many mechanisms of metabolic homeostasis, including extracellular signaling in olfaction. Data is available via ProteomeXChange with identifier PXD011371" |
| Keywords: | CID-nano-LC-MS/MS O-GlcNAc fluorescence spectroscopy odorant-binding protein pheromone phosphorylation; |
| Notes: | "PubMed-not-MEDLINENagnan-Le Meillour, Patricia Joly, Alexandre Le Danvic, Chrystelle Marie, Arul Zirah, Severine Cornard, Jean-Paul eng Switzerland 2019/02/12 Front Endocrinol (Lausanne). 2019 Jan 25; 9:816. doi: 10.3389/fendo.2018.00816. eCollection 2018" |
