title: Generation of amyloid beta protein from a presenilin-1 and betaAPP complex.
abstract: Presenilin-1 (PS1) is a causative gene in early onset familial Alzheimer's disease (FAD). FAD-linked mutant PS1s significantly increased Abeta40 and Abeta42(43) levels (P < 0.001) and decreased the production of an 11.4 kD (beta-stub) and an 8.7 kD (alpha-stub) carboxyl-terminal fragment of amyloid beta precursor protein (betaAPP-CTFs) (P < 0.01). In the 2% CHAPS extracted lysates, the complex containing the amino-terminal fragment of PS1 (PS1-NTF), the carboxyl-terminal fragments of PS1 (PS1-CTF), and betaAPP-CTFs was identified. Incubation of this isolated complex at pH 6.4 showed the direct generation of Abeta40 and gamma-stub from this complex. This reaction was inhibited by a gamma-secretase inhibitor. The degrading rate of a co-precipitated beta-stub was facilitated under the presence of FAD-linked mutant PS1s. This findings suggest that the direct generation of Abeta from the complex may play an important role in the pathogenesis of Alzheimer's disease.
authors.affiliation: Department of Neurology, Gunma University School of Medicine, Maebashi, Gunma, Japan.
authors.forename: Masami
authors.initials: M
authors.lastname: Shizuka-Ikeda
authors.forename: Etsuro
authors.initials: E
authors.lastname: Matsubara
authors.forename: Masaki
authors.initials: M
authors.lastname: Ikeda
authors.forename: Mitsuyasu
authors.initials: M
authors.lastname: Kanai
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Tomidokoro
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Ikeda
authors.forename: Mitsunori
authors.initials: M
authors.lastname: Watanabe
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kawarabayashi
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Harigaya
authors.forename: Koichi
authors.initials: K
authors.lastname: Okamoto
authors.forename: Kei
authors.initials: K
authors.lastname: Maruyama
authors.forename: Eduardo M
authors.initials: EM
authors.lastname: Castaño
authors.forename: Peter
authors.initials: P
authors.lastname: St  George-Hyslop
authors.forename: Mikio
authors.initials: M
authors.lastname: Shoji
mesh_terms: D053829:Amyloid Precursor Protein Secretases; D016229:Amyloid beta-Peptides / Q000096:biosynthesis*; D016564:Amyloid beta-Protein Precursor / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D016282:Aspartic Acid Endopeptidases; D019556:COS Cells; D002460:Cell Line; D010450:Endopeptidases / Q000378:metabolism; D006801:Humans; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D010446:Peptide Fragments / Q000032:analysis / Q000096:biosynthesis; D053764:Presenilin-1
chemical_list: D016229:Amyloid beta-Peptides; D016564:Amyloid beta-Protein Precursor; D046911:Macromolecular Substances; D008565:Membrane Proteins; C508853:PSEN1 protein, human; D010446:Peptide Fragments; D053764:Presenilin-1; C078592:amyloid beta-protein (1-40); C075222:amyloid beta-protein (1-42); D053829:Amyloid Precursor Protein Secretases; D010450:Endopeptidases; D016282:Aspartic Acid Endopeptidases; C509280:BACE1 protein, human