title: Direct High Affinity Interaction between Aβ42 and GSK3α Stimulates Hyperphosphorylation of Tau. A New Molecular Link in Alzheimer's Disease?
abstract: Amyloid β peptide (Aβ42) assemblies are considered central to the development of Alzheimer's disease, but the mechanism of this toxicity remains unresolved. We screened protein microarrays with on-pathway oligomeric Aβ42 to identify candidate proteins interacting with toxic Aβ42 species. Samples prepared from Alexa546-Aβ42 and Aβ42 monomers at 1:5 molar ratio were incubated with the array during a time window of the amyloid fibril formation reaction during which the maximum number of transient oligomers exist in the reaction flux. A specific interaction was detected between Aβ42 and glycogen synthase kinase 3α (GSK3α), a kinase previously implicated in the disease pathology. This interaction was validated with anti-GSK3α immunoprecipitation assays in neuronal cell lysates. Confocal microscopy studies further identified colocalization of Aβ42 and GSK3α in neurites of mature primary mouse neurons. A high binding affinity (KD = 1 nM) was measured between Alexa488-Aβ42 and GSK3α in solution using thermophoresis. An even lower apparent KD was estimated between GSK3α and dextran-immobilized Aβ42 in surface plasmon resonance experiments. Parallel experiments with GSK3β also identified colocalization and high affinity binding to this isoform. GSK3α-mediated hyperphosphorylation of the protein tau was found to be stimulated by Aβ42 in in vitro phosphorylation assays and identified a functional relationship between the proteins. We uncover a direct and functional molecular link between Aβ42 and GSK3α, which opens an important avenue toward understanding the mechanism of Aβ42-mediated neuronal toxicity in Alzheimer's disease.
authors.affiliation: Department of Biochemistry and Structural Biology, Chemical Centre, Lund University , P O Box 124, SE22100 Lund, Sweden.|Department of Experimental Medical Science, Lund University , SE22100 Lund, Sweden.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Dunning
authors.affiliation: School of Biomolecular & Biomedical Science, Conway Institute, University College Dublin , Belfield, Dublin 4, Ireland.
authors.forename: Gavin
authors.initials: G
authors.lastname: McGauran
authors.affiliation: Department of Experimental Medical Science, Lund University , SE22100 Lund, Sweden.
authors.forename: Katarina
authors.initials: K
authors.lastname: Willén
authors.affiliation: Department of Experimental Medical Science, Lund University , SE22100 Lund, Sweden.
authors.forename: Gunnar K
authors.initials: GK
authors.lastname: Gouras
authors.affiliation: School of Biomolecular & Biomedical Science, Conway Institute, University College Dublin , Belfield, Dublin 4, Ireland.
authors.forename: David J
authors.initials: DJ
authors.lastname: O'Connell
authors.affiliation: Department of Biochemistry and Structural Biology, Chemical Centre, Lund University , P O Box 124, SE22100 Lund, Sweden.
authors.forename: Sara
authors.initials: S
authors.lastname: Linse
mesh_terms: D016229:Amyloid beta-Peptides / Q000378:metabolism* / Q000494:pharmacology; D016564:Amyloid beta-Protein Precursor / Q000378:metabolism; D000818:Animals; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology; D004305:Dose-Response Relationship, Drug; D004622:Embryo, Mammalian; D038362:Glycogen Synthase Kinase 3 / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D000071679:Glycogen Synthase Kinase 3 beta / Q000235:genetics / Q000378:metabolism; D006801:Humans; D047468:Immunoprecipitation; D051379:Mice; D018613:Microscopy, Confocal; D009154:Mutation / Q000235:genetics; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism* / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects / Q000502:physiology; D020349:Surface Plasmon Resonance; D013997:Time Factors; D014162:Transfection; D016875:tau Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: C545487:APP protein, human; D016229:Amyloid beta-Peptides; D016564:Amyloid beta-Protein Precursor; D010446:Peptide Fragments; C075222:amyloid beta-protein (1-42); D016875:tau Proteins; D000071679:Glycogen Synthase Kinase 3 beta; D038362:Glycogen Synthase Kinase 3; C448021:glycogen synthase kinase 3 alpha
keywords: Interactome; amyloid beta; microarray screen; signaling; target protein