title: The Tyr216 phosphorylated form of GSK3β contributes to tau phosphorylation at PHF-1 epitope in response to Aβ in the nucleus of SH-SY5Y cells.
abstract: OBJECTIVE
  GSK3β activation in Aβ conditions leading to tau phosphorylation at pathological sites is a well-known phenomenon. However, the serine/tyrosine phosphorylation processes implied in Aβ-induced GSK3β activation and responsible for tau phosphorylation, especially at the GSK3β specific Ser396/Ser404 (PHF-1) site, are still debated.
  
  
  METHODS
  Experiments were performed on SH-SY5Y cells exposed to 20μM Aβ1-42 in a time ranging from 5min to 8h. The phophorylated forms (Ser9 and Tyr216) of GSK3β and pTau at PHF-1 epitope were measured by immunoblotting in nuclear extracts.
  
  
  RESULTS
  We showed a superimposable time-dependent increase of nuclear pGSK3βTyr216 and nuclear pTau at PHF-1 site, both reaching their maximal level after 8h of Aβ1-42 exposure. In addition, nuclear accumulation of pTau is accompanied by its cytoplasmic decrease suggesting that pTau is translocated in response to Aβ treatment. Besides, our experiments showed that specific pGSK3βTyr216 inhibition is required to drop nuclear pTau, ensuring the involvement of Tyr216 phosphorylation in Aβ-mediated tau phosphorylation at PHF-1 epitope.
  
  
  CONCLUSIONS
  These data suggested that in response to Aβ exposure in SH-SY5Y cells, GSK3β activation is performed through Tyr216 phosphorylation and resulted in tau phosphorylation at PHF-1 epitope and in its translocation.
authors.affiliation: Université de Poitiers, Groupe de Recherche sur le Vieillissement Cérébral, GRéViC, EA 3808, Poitiers, France.
authors.forename: Anastasia
authors.initials: A
authors.lastname: Noel
authors.affiliation: Université de Poitiers, UFR Médecine&Pharmacie, Service de Biochimie et Toxicologie, 6 rue de la Milétrie, TSA 51115, 86073 Poitiers Cedex 9, France.
authors.forename: Laurence
authors.initials: L
authors.lastname: Barrier
authors.affiliation: Université de Poitiers, UFR Médecine&Pharmacie, Service de Biochimie et Toxicologie, 6 rue de la Milétrie, TSA 51115, 86073 Poitiers Cedex 9, France. Electronic address: sabrina.ingrand@univ-poitiers.fr.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Ingrand
mesh_terms: D016229:Amyloid beta-Peptides / Q000378:metabolism*; D000911:Antibodies, Monoclonal / Q000276:immunology*; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism*; D000939:Epitopes / Q000276:immunology / Q000378:metabolism*; D000071679:Glycogen Synthase Kinase 3 beta / Q000378:metabolism*; D006801:Humans; D010766:Phosphorylation; D014443:Tyrosine / Q000378:metabolism*; D016875:tau Proteins / Q000378:metabolism*
chemical_list: D016229:Amyloid beta-Peptides; D000911:Antibodies, Monoclonal; D000939:Epitopes; C085349:PHF-1 monoclonal antibody; D016875:tau Proteins; D014443:Tyrosine; C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta
keywords: Abeta; Glycogen synthase kinase-3 beta; PHF-1 epitope; SH-SY5Y cell lines; Tau phosphorylation; Tyrosine216 phosphorylation