title: Gi-coupled P2Y-ADP receptor mediates GSK-3 phosphorylation and beta-catenin nuclear translocation in granule neurons.
abstract: Glycogen synthase kinase-3 (GSK-3) is a multifaceted enzyme involved in development, neurogenesis, and survival at the CNS. We investigated nucleotides signaling to GSK-3 in cerebellar granule neurons and found that the metabotropic agonist 2-methyl-thio-ADP (2MeSADP) was able to induce GSK-3 phosphorylation and inhibition of its catalytic activity. 2MeSADP could be acting through several P2Y-ADP receptors expressed in granule neurons, as RT-PCR expression was found for P2Y(1), P2Y(12), and P2Y(13) receptors, but the pharmacological data fitted well with a Gi-coupled P2Y(13) receptor: the effect was sensitive to pertussis toxin, was unaffected by specific antagonists of P2Y(1) and P2Y(12) receptors, such as 2'-deoxy-N(6)-methyl-adenosine 3',5'-diphosphate and 2-methyl-thio-AMP, respectively, and the EC(50) values for 2MeSADP and ADP were in the same low nanomolar range. 2MeSADP was able to phosphorylate and activate extracellular signal-regulated kinase (ERK)-1,2 and Akt proteins, but its effect on GSK-3 phosphorylation was primarily dependent on the phosphatidyl inositol-3 kinase (PI3-K)/Akt pathway, as it was abolished by the PI3-K inhibitor wortmannin. GSK-3 inactivation by 2MeSADP in granule neurons resulted in nuclear translocation of its substrate beta-catenin, which functions as a transcriptional regulator, this effect being lost with wortmaninn. The present study first describes the coupling of a Gi-coupled P2Y(13)-like receptor to GSK-3 and beta-catenin through PI3-K/Akt signaling.
authors.affiliation: Department of Biochemistry, Veterinary Faculty, Complutense University of Madrid, Madrid, Spain.
authors.forename: Felipe
authors.initials: F
authors.lastname: Ortega
authors.forename: Raquel
authors.initials: R
authors.lastname: Pérez-Sen
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Miras-Portugal
mesh_terms: D000244:Adenosine Diphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism*; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000378:metabolism*; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure*; D010766:Phosphorylation / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D018048:Receptors, Purinergic P2 / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013873:Thionucleotides / Q000494:pharmacology; D013997:Time Factors; D051176:beta Catenin / Q000378:metabolism*
chemical_list: D004791:Enzyme Inhibitors; D018048:Receptors, Purinergic P2; D013873:Thionucleotides; D051176:beta Catenin; C002480:methylthio-ADP; D000244:Adenosine Diphosphate; D038362:Glycogen Synthase Kinase 3; D019206:GTP-Binding Protein alpha Subunits, Gi-Go