title: ADAM10 is the physiologically relevant, constitutive alpha-secretase of the amyloid precursor protein in primary neurons.
abstract: The amyloid precursor protein (APP) undergoes constitutive shedding by a protease activity called alpha-secretase. This is considered an important mechanism preventing the generation of the Alzheimer's disease amyloid-beta peptide (Abeta). alpha-Secretase appears to be a metalloprotease of the ADAM family, but its identity remains to be established. Using a novel alpha-secretase-cleavage site-specific antibody, we found that RNAi-mediated knockdown of ADAM10, but surprisingly not of ADAM9 or 17, completely suppressed APP alpha-secretase cleavage in different cell lines and in primary murine neurons. Other proteases were not able to compensate for this loss of alpha-cleavage. This finding was further confirmed by mass-spectrometric detection of APP-cleavage fragments. Surprisingly, in different cell lines, the reduction of alpha-secretase cleavage was not paralleled by a corresponding increase in the Abeta-generating beta-secretase cleavage, revealing that both proteases do not always compete for APP as a substrate. Instead, our data suggest a novel pathway for APP processing, in which ADAM10 can partially compete with gamma-secretase for the cleavage of a C-terminal APP fragment generated by beta-secretase. We conclude that ADAM10 is the physiologically relevant, constitutive alpha-secretase of APP.
authors.affiliation: Adolf-Butenandt-Institute, Biochemistry, Ludwig-Maximilians-University, Munich, Germany.
authors.forename: Peer-Hendrik
authors.initials: PH
authors.lastname: Kuhn
authors.forename: Huanhuan
authors.initials: H
authors.lastname: Wang
authors.forename: Bastian
authors.initials: B
authors.lastname: Dislich
authors.forename: Alessio
authors.initials: A
authors.lastname: Colombo
authors.forename: Ulrike
authors.initials: U
authors.lastname: Zeitschel
authors.forename: Joachim W
authors.initials: JW
authors.lastname: Ellwart
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Kremmer
authors.forename: Steffen
authors.initials: S
authors.lastname: Rossner
authors.forename: Stefan F
authors.initials: SF
authors.lastname: Lichtenthaler
mesh_terms: D051722:ADAM Proteins / Q000378:metabolism*; D000072197:ADAM10 Protein; D053829:Amyloid Precursor Protein Secretases / Q000378:metabolism*; D016564:Amyloid beta-Protein Precursor / Q000378:metabolism*; D000818:Animals; D002460:Cell Line; D006801:Humans; D013058:Mass Spectrometry; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D009474:Neurons / Q000201:enzymology* / Q000378:metabolism
chemical_list: D016564:Amyloid beta-Protein Precursor; C078201:Aplp1 protein, mouse; D008565:Membrane Proteins; D053829:Amyloid Precursor Protein Secretases; D051722:ADAM Proteins; D000072197:ADAM10 Protein; C491234:Adam10 protein, mouse