title: Presenilin-1 mutations of leucine 166 equally affect the generation of the Notch and APP intracellular domains independent of their effect on Abeta 42 production.
abstract: The Alzheimer's disease (AD)-associated presenilin (PS) proteins are required for the gamma-secretase cleavages of the beta-amyloid precursor protein and the site 3 (S3) protease cleavage of Notch. These intramembrane cleavages release amyloid-beta peptide (Abeta), including the pathogenic 42-aa variant (Abeta(42)), as well as the beta-amyloid precursor protein and the Notch intracellular domains (AICD, NICD). Whereas Abeta is generated by endoproteolysis in the middle of the transmembrane domain, AICD and NICD are generated by cleavages at analogous positions close to the cytoplasmic border of the transmembrane domain. Numerous mutations causing familial AD (FAD) that all cause increased production of Abeta(42) have been found in the PS1 gene. Here we have investigated the previously uncharacterized, very aggressive FAD mutation L166P that causes onset of AD in adolescence. Strikingly, the PS1 L166P mutation not only induces an exceptionally high increase of Abeta(42) production but also impairs NICD production and Notch signaling, as well as AICD generation. Thus, FAD-associated PS mutants cannot only affect the generation of NICD, but also that of AICD. Moreover, further analysis with artificial L166 mutants revealed that the gamma-secretase cleavage at position 40/42 and the S3-like gamma-secretase cleavage at position 49 of the Abeta domain are both differentially affected by PS1 L166 mutants. Finally, we show that PS1 L166 mutants affect the generation of NICD and AICD in a similar manner, supporting the concept that S3 protease and S3-like gamma-secretase cleavages are mediated by identical proteolytic activities.
authors.affiliation: Adolf Butenandt-Institute, Department of Biochemistry, Laboratory for Alzheimer's Disease Research, Ludwig-Maximilians-University, 80336 Munich, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Moehlmann
authors.forename: Edith
authors.initials: E
authors.lastname: Winkler
authors.forename: Xuefeng
authors.initials: X
authors.lastname: Xia
authors.forename: Dieter
authors.initials: D
authors.lastname: Edbauer
authors.forename: Jill
authors.initials: J
authors.lastname: Murrell
authors.forename: Anja
authors.initials: A
authors.lastname: Capell
authors.forename: Christoph
authors.initials: C
authors.lastname: Kaether
authors.forename: Hui
authors.initials: H
authors.lastname: Zheng
authors.forename: Bernardino
authors.initials: B
authors.lastname: Ghetti
authors.forename: Christian
authors.initials: C
authors.lastname: Haass
authors.forename: Harald
authors.initials: H
authors.lastname: Steiner
mesh_terms: D000544:Alzheimer Disease / Q000235:genetics*; D019943:Amino Acid Substitution; D016229:Amyloid beta-Peptides / Q000235:genetics*; D016564:Amyloid beta-Protein Precursor / Q000737:chemistry / Q000378:metabolism*; D002460:Cell Line; D005347:Fibroblasts; D006801:Humans; D007668:Kidney; D007930:Leucine; D008565:Membrane Proteins / Q000737:chemistry / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism*; D009154:Mutation; D010446:Peptide Fragments / Q000235:genetics*; D053764:Presenilin-1; D051880:Receptors, Notch; D011994:Recombinant Proteins / Q000378:metabolism; D014162:Transfection
chemical_list: D016229:Amyloid beta-Peptides; D016564:Amyloid beta-Protein Precursor; D008565:Membrane Proteins; C508853:PSEN1 protein, human; D010446:Peptide Fragments; D053764:Presenilin-1; D051880:Receptors, Notch; D011994:Recombinant Proteins; C075222:amyloid beta-protein (1-42); D007930:Leucine