title: Amyloid-beta precursor protein mediates neuronal toxicity of amyloid beta through Go protein activation.
abstract: Amyloid beta (Abeta) is a metabolic product of amyloid-beta precursor protein (APP). Deposition of Abeta in the brain and neuronal degeneration are characteristic hallmarks of Alzheimer's disease (AD). Abeta induces neuronal degeneration, but the mechanism of neurotoxicity remains elusive. Here we show that overexpression of APP renders hippocampal neurons vulnerable to Abeta toxicity. Deletion of the extracellular Abeta sequence of APP prevents binding of APP to Abeta, and abolishes toxicity. Abeta toxicity is also abrogated by deletion of the cytoplasmic domain of APP, or by deletions comprising the Go protein-binding sequence of APP. Treatment with Pertussis toxin (PTX) abrogates APP-dependent toxicity of Abeta. Overexpression of PTX-insensitive Galpha-o subunit, but not Galpha-i subunit, of G protein restores Abeta toxicity in the presence of PTX, and this requires the integrity of APP-binding site for Go protein. Altogether, these experiments indicate that interaction of APP with toxic Abeta-species promotes toxicity in hippocampal neurons by a mechanism that involves APP-mediated Go protein activation, revealing an Abeta-receptor-like function of APP directly implicated in neuronal degeneration in AD.
authors.affiliation: Instituto de Investigación Médica- CONICET, Córdoba, Argentina.
authors.forename: Francisco
authors.initials: F
authors.lastname: Sola Vigo
authors.forename: Gabriela
authors.initials: G
authors.lastname: Kedikian
authors.forename: Lorena
authors.initials: L
authors.lastname: Heredia
authors.forename: Florencia
authors.initials: F
authors.lastname: Heredia
authors.forename: Alberto Díaz
authors.initials: AD
authors.lastname: Añel
authors.forename: Alberto Luis
authors.initials: AL
authors.lastname: Rosa
authors.forename: Alfredo
authors.initials: A
authors.lastname: Lorenzo
mesh_terms: D000544:Alzheimer Disease / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D016229:Amyloid beta-Peptides / Q000378:metabolism* / Q000633:toxicity; D016564:Amyloid beta-Protein Precursor / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites / Q000235:genetics; D001921:Brain / Q000378:metabolism* / Q000503:physiopathology; D002478:Cells, Cultured; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000235:genetics / Q000378:metabolism*; D006624:Hippocampus / Q000378:metabolism / Q000503:physiopathology; D006801:Humans; D009410:Nerve Degeneration / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology; D009474:Neurons / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D037342:Pertussis Toxin / Q000494:pharmacology; D011485:Protein Binding / Q000235:genetics; D017434:Protein Structure, Tertiary / Q000502:physiology; D051381:Rats
chemical_list: D016229:Amyloid beta-Peptides; D016564:Amyloid beta-Protein Precursor; D037342:Pertussis Toxin; D019206:GTP-Binding Protein alpha Subunits, Gi-Go