title: The cellular prion protein interacts with the tissue non-specific alkaline phosphatase in membrane microdomains of bioaminergic neuronal cells.
abstract: BACKGROUND
  The cellular prion protein, PrP(C), is GPI anchored and abundant in lipid rafts. The absolute requirement of PrP(C) in neurodegeneration associated to prion diseases is well established. However, the function of this ubiquitous protein is still puzzling. Our previous work using the 1C11 neuronal model, provided evidence that PrP(C) acts as a cell surface receptor. Besides a ubiquitous signaling function of PrP(C), we have described a neuronal specificity pointing to a role of PrP(C) in neuronal homeostasis. 1C11 cells, upon appropriate induction, engage into neuronal differentiation programs, giving rise either to serotonergic (1C11(5-HT)) or noradrenergic (1C11(NE)) derivatives.
  
  
  RESULTS
  The neuronal specificity of PrP(C) signaling prompted us to search for PrP(C) partners in 1C11-derived bioaminergic neuronal cells. We show here by immunoprecipitation an association of PrP(C) with an 80 kDa protein identified by mass spectrometry as the tissue non-specific alkaline phosphatase (TNAP). This interaction occurs in lipid rafts and is restricted to 1C11-derived neuronal progenies. Our data indicate that TNAP is implemented during the differentiation programs of 1C11(5-HT) and 1C11(NE) cells and is active at their cell surface. Noteworthy, TNAP may contribute to the regulation of serotonin or catecholamine synthesis in 1C11(5-HT) and 1C11(NE) bioaminergic cells by controlling pyridoxal phosphate levels. Finally, TNAP activity is shown to modulate the phosphorylation status of laminin and thereby its interaction with PrP.
  
  
  CONCLUSIONS
  The identification of a novel PrP(C) partner in lipid rafts of neuronal cells favors the idea of a role of PrP in multiple functions. Because PrP(C) and laminin functionally interact to support neuronal differentiation and memory consolidation, our findings introduce TNAP as a functional protagonist in the PrP(C)-laminin interplay. The partnership between TNAP and PrP(C) in neuronal cells may provide new clues as to the neurospecificity of PrP(C) function.
authors: Différenciation cellulaire et Prions, Institut Pasteur, Département de Biologie Cellulaire et Infection, Paris, France. myriam.ermonval@pasteur.fr
authors: Myriam
authors: M
authors: Ermonval
authors: Anne
authors: A
authors: Baudry
authors: Florence
authors: F
authors: Baychelier
authors: Elodie
authors: E
authors: Pradines
authors: Mathéa
authors: M
authors: Pietri
authors: Kimimitsu
authors: K
authors: Oda
authors: Benoît
authors: B
authors: Schneider
authors: Sophie
authors: S
authors: Mouillet-Richard
authors: Jean-Marie
authors: JM
authors: Launay
authors: Odile
authors: O
authors: Kellermann
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001679:Biogenic Amines / Q000378:metabolism*; D015153:Blotting, Western; D002395:Catecholamines / Q000096:biosynthesis; D002454:Cell Differentiation; D002462:Cell Membrane / Q000378:metabolism; D006706:Homeostasis; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D010766:Phosphorylation; D018621:PrPC Proteins / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D012701:Serotonin / Q000096:biosynthesis
chemical_list: D001679:Biogenic Amines; D002395:Catecholamines; D018621:PrPC Proteins; D012701:Serotonin; D000469:Alkaline Phosphatase