Ludwig-Maximilians-Universität, Chair of Metabolic Biochemistry

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ADAM9 inhibition increases membrane activity of ADAM10 and controls {alpha}secretase processing of amyloid precursor protein

J Biol Chem. 2011 Sep 28. [Epub ahead of print]

Authors/Editors: Moss ML
Powell G
Miller MA
Bin Q
Sang QX
De Strooper B
Tesseur I
Taverna M
Zhong JL
Dingwall C
Ferdous T
Schlomann U
Zhou P
Griffith L
Lauffenberger D
Petrovich R
Bartsch JW
Publication Date: 2011
Type of Publication: Journal Article


Prodomains of ADAM metallopeptidases can act as highly specific intra- and intermolecular inhibitors of ADAM catalytic activity. Murine ADAM9 prodomain (proA9; amino acid 24-204), expressed and characterized from E. coli, is a competitive inhibitor of human ADAM9 catalytic/disintegrin domain with an overall inhibition constant of 280plus-or-minus sign34nM and high specificity towards ADAM9. In SY5Y neuroblastoma cells over-expressing amyloid precursor protein (APP), proA9 treatment reduces the amount of ADAM10 enzyme in the media whilst increasing membrane-bound ADAM10 as shown by activity assays with fluorescent peptide substrates and Western blot analysis. An increase in membrane-bound ADAM10 generates higher levels of soluble amyloid precursor protein alpha (sAPP-alpha) in the media, whereas sAPPbeta levels are decreased, demonstrating that inhibition of ADAM9 increases alpha-secretase activity. Furthermore, quantification of physiological substrates for ADAM10 such as epidermal growth factor (EGF), HER2, osteoactivin, and CD40-Ligand also reveal an increase of ADAM10 substrate levels from the media of BT474 breast tumor cells incubated with proA9. Taken together, our results demonstrate a novel type of ADAM10 regulation, in which inhibition of ADAM9 catalytic activity can be used to control shedding of APP by enhancing alpha-secretase activity, a key regulatory step in Alzheimers disease.

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