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Schöbel, S.* ; Neumann, S.* ; Hertweck, M.* ; Dislich, B.* ; Kuhn, P.H.* ; Kremmer, E. ; Seed, B.* ; Baumeister, R.* ; Haass, C.* ; Lichtenthaler, S.F.*

A novel sorting nexin modulates endocytic trafficking and alpha-secretase cleavage of the amyloid precursor protein.

J. Biol. Chem. 283, 14257-14268 (2008)
DOI
Open Access Gold as soon as Publ. Version/Full Text is submitted to ZB.
Ectodomain shedding of the amyloid precursor protein (APP) by the two proteases alpha- and beta-secretase is a key regulatory event in the generation of the Alzheimer disease amyloid beta peptide (Abeta). beta-Secretase catalyzes the first step in Abeta generation, whereas alpha-secretase cleaves within the Abeta domain, prevents Abeta generation, and generates a secreted form of APP with neuroprotective properties. At present, little is known about the cellular mechanisms that control APP alpha-secretase cleavage and Abeta generation. To explore the contributory pathways, we carried out an expression cloning screen. We identified a novel member of the sorting nexin (SNX) family of endosomal trafficking proteins, called SNX33, as a new activator of APP alpha-secretase cleavage. SNX33 is a homolog of SNX9 and was found to be a ubiquitously expressed phosphoprotein. Exogenous expression of SNX33 in cultured cells increased APP alpha-secretase cleavage 4-fold but surprisingly had little effect on beta-secretase cleavage. This effect was similar to the expression of the dominant negative dynamin-1 mutant K44A. SNX33 bound the endocytic GTPase dynamin and reduced the rate of APP endocytosis in a dynamin-dependent manner. This led to an increase of APP at the plasma membrane, where alpha-secretase cleavage mostly occurs. In summary, our study identifies SNX33 as a new endocytic protein, which modulates APP endocytosis and APP alpha-secretase cleavage, and demonstrates that the rate of APP endocytosis is a major control factor for APP alpha-secretase cleavage.
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Publication type Article: Journal article
Document type Scientific Article
ISSN (print) / ISBN 0021-9258
e-ISSN 1083-351X
Journal Journal of Biological Chemistry, The
Quellenangaben Volume: 283, Issue: 21, Pages: 14257-14268 Article Number: , Supplement: ,
Publisher American Society for Biochemistry and Molecular Biology
Reviewing status Peer reviewed
Institute(s) Institute of Molecular Immunology (IMI)