title: Dual role of alpha-secretase cleavage in the regulation of gamma-secretase activity for amyloid production.
abstract: Processing of the amyloid precursor protein (APP) by β- and γ-secretases generates pathogenic β-amyloid (Aβ) peptides associated with Alzheimer disease (AD), whereas cleavage of APP by α-secretases precludes Aβ formation. Little is known about the role of α-secretase cleavage in γ-secretase regulation. Here, we show that α-secretase-cleaved APP C-terminal product (αCTF) functions as an inhibitor of γ-secretase. We demonstrate that the substrate inhibitory domain (ASID) within αCTF, which is bisected by the α-secretase cleavage site, contributes to this negative regulation because deleting or masking this domain turns αCTF into a better substrate for γ-secretase. Moreover, α-secretase cleavage can potentiate the inhibitory effect of ASID. Inhibition of γ-secretase activity by αCTF is observed in both in vitro and cellular systems. This work reveals an unforeseen role for α-secretase in generating an endogenous γ-secretase inhibitor that down-regulates the production of Aβ. Deregulation of this feedback mechanism may contribute to the pathogenesis of AD.
authors.affiliation: Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10065, USA.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Tian
authors.forename: Christina J
authors.initials: CJ
authors.lastname: Crump
authors.forename: Yue-Ming
authors.initials: YM
authors.lastname: Li
mesh_terms: D051722:ADAM Proteins / Q000235:genetics / Q000378:metabolism; D000072197:ADAM10 Protein; D000072198:ADAM17 Protein; D000544:Alzheimer Disease / Q000378:metabolism; D000595:Amino Acid Sequence; D000682:Amyloid / Q000235:genetics / Q000378:metabolism*; D053829:Amyloid Precursor Protein Secretases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D016564:Amyloid beta-Protein Precursor / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D002460:Cell Line; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D010455:Peptides / Q000235:genetics / Q000378:metabolism
chemical_list: D000682:Amyloid; D016564:Amyloid beta-Protein Precursor; D008565:Membrane Proteins; D010455:Peptides; D053829:Amyloid Precursor Protein Secretases; D051722:ADAM Proteins; D000072197:ADAM10 Protein; C491236:ADAM10 protein, human; D000072198:ADAM17 Protein