title: Generation of the amyloid-beta peptide N terminus in Saccharomyces cerevisiae expressing human Alzheimer's amyloid-beta precursor protein.
abstract: The Alzheimer's amyloid-beta precursor protein (betaAPP) is a type 1 membrane-spanning protein from which the Alzheimer's disease amyloid-beta peptide (Abeta) is proteolytically derived. To date, attempts to identify the enzymes responsible for Abeta generation have failed. Here we report the accumulation of Abeta-immunoreactive peptides in yeast expressing human betaAPP. Characterization of these peptides by metabolic labeling, immunoprecipitation with Abeta-specific antibodies, and N-terminal radiosequencing indicates that these peptides include the Abeta peptide at their N termini. The Abeta-like peptides generated in yeast were recovered predominantly as 8- and 12-14-kDa species. A 4-kDa species was recovered either when a protease-deficient strain was used to prevent breakdown or when the 8- and 12-14-kDa species were treated with disaggregating agents. The likely existence in yeast of enzymes generating the Abeta N terminus indicates that the molecular identification of yeast beta-secretase-like enzymes may be accomplished using genetic screens or empirical approaches based upon the sequenced genome of Saccharomyces cerevisiae.
authors.affiliation: Laboratory of Molecular Neuroscience, Fisher Center for Research on Alzheimer Disease, The Rockefeller University, New York, New York 10021, USA.
authors.forename: J P
authors.initials: JP
authors.lastname: Greenfield
authors.forename: H
authors.initials: H
authors.lastname: Xu
authors.forename: P
authors.initials: P
authors.lastname: Greengard
authors.forename: S
authors.initials: S
authors.lastname: Gandy
authors.forename: M
authors.initials: M
authors.lastname: Seeger
mesh_terms: D000544:Alzheimer Disease / Q000378:metabolism; D000595:Amino Acid Sequence; D053829:Amyloid Precursor Protein Secretases; D016229:Amyloid beta-Peptides / Q000737:chemistry / Q000378:metabolism*; D016564:Amyloid beta-Protein Precursor / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D016282:Aspartic Acid Endopeptidases; D004591:Electrophoresis, Polyacrylamide Gel; D010450:Endopeptidases / Q000378:metabolism; D015870:Gene Expression; D006801:Humans; D008970:Molecular Weight; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D011233:Precipitin Tests; D011499:Protein Processing, Post-Translational; D011993:Recombinant Fusion Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D016229:Amyloid beta-Peptides; D016564:Amyloid beta-Protein Precursor; D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins; D053829:Amyloid Precursor Protein Secretases; D010450:Endopeptidases; D016282:Aspartic Acid Endopeptidases; C509280:BACE1 protein, human