Aberrant Amyloid Precursor Protein (APP) Processing in Hereditary Forms of Alzheimer Disease Caused by APP Familial Alzheimer Disease Mutations Can Be Rescued by Mutations in the APP GxxxG Motif

作者:Munter Lisa Marie; Botev Anne; Richter Luise; Hildebrand Peter W; Althoff Veit; Weise Christoph; Kaden Daniela; Multhaup Gerd*
来源:JOURNAL OF BIOLOGICAL CHEMISTRY, 2010, 285(28): 21636-21643.
DOI:10.1074/jbc.M109.088005

摘要

The identification of hereditary familial Alzheimer disease (FAD) mutations in the amyloid precursor protein (APP) and presenilin-1 (PS1) corroborated the causative role of amyloid-beta peptides with 42 amino acid residues (A beta 42) in the pathogenesis of AD. Although most FAD mutations are known to increase A beta 42 levels, mutations within the APP GxxxG motif are known to lower A beta 42 levels by attenuating transmembrane sequence dimerization. Here, we show that aberrant A beta 42 levels of FAD mutations can be rescued by GxxxG mutations. The combination of the APP-GxxxG mutation G33A with APP-FAD mutations yielded a constant 60% decrease of A beta 42 levels and a concomitant 3-fold increase of A beta 38 levels compared with the Gly(33) wild-type as determined by ELISA. In the presence of PS1-FAD mutations, the effects of G33A were attenuated, apparently attributable to a different mechanism of PS1-FAD mutants compared with APP-FAD mutants. Our results contribute to a general understanding of the mechanism how APP is processed by the gamma-secretase module and strongly emphasize the potential of the GxxxG motif in the prevention of sporadic AD as well as FAD.