17 Kuhn, Peer-Hendrik Wang, Huanhuan Dislich, Bastian Colombo, Alessio Zeitschel, Ulrike Ellwart, Joachim W Kremmer, Elisabeth Rossner, Steffen Lichtenthaler, Stefan AG Lichtenthaler The EMBO journal The EMBO journal Wiley Hoboken, NJ [u.a.] 0261-4189 10.1038/emboj.2010.167 English 3020-3032 17 29 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. PUB:(DE-HGF)16, ; 0, ; ADAM Proteins: metabolism ADAM10 Protein Amyloid Precursor Protein Secretases: metabolism Amyloid beta-Protein Precursor: metabolism Animals Cell Line Humans Mass Spectrometry Membrane Proteins: metabolism Mice Neurons: enzymology Neurons: metabolism Amyloid beta-Protein Precursor Aplp1 protein, mouse Membrane Proteins Amyloid Precursor Protein Secretases ADAM Proteins ADAM10 Protein Adam10 protein, mouse Journal Article 2010 DZNE-2020-02442 2010 pmc:PMC2944055 pmid:20676056 https://pub.dzne.de/record/136120 https://doi.org/10.1038/emboj.2010.167