title: Functional analysis of the transmembrane domains of presenilin 1: participation of transmembrane domains 2 and 6 in the formation of initial substrate-binding site of gamma-secretase.
abstract: gamma-Secretase is a multimeric membrane protein complex composed of presenilin (PS), nicastrin, Aph-1, and Pen-2, which mediates intramembrane proteolysis of a range of type I transmembrane proteins. We previously analyzed the functional roles of the N-terminal transmembrane domains (TMDs) 1-6 of PS1 in the assembly and proteolytic activity of the gamma-secretase using a series of TMD-swap PS1 mutants. Here we applied the TMD-swap method to all the TMDs of PS1 for the structure-function analysis of the proteolytic mechanism of gamma-secretase. We found that TMD2- or -6-swapped mutant PS1 failed to bind the helical peptide-based, substrate-mimic gamma-secretase inhibitor. Cross-linking experiments revealed that both TMD2 and TMD6 of PS1 locate in proximity to the TMD9, the latter being implicated in the initial substrate binding. Taken together, our data suggest that TMD2 and the luminal side of TMD6 are involved in the formation of the initial substrate-binding site of the gamma-secretase complex.
authors.affiliation: Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan.
authors.forename: Naoto
authors.initials: N
authors.lastname: Watanabe
authors.forename: Image Image
authors.initials: II
authors.lastname: Image Image
authors.forename: Shizuka
authors.initials: S
authors.lastname: Takagi
authors.forename: Image Image
authors.initials: II
authors.lastname: Image Image
authors.forename: Aya
authors.initials: A
authors.lastname: Tominaga
authors.forename: Image
authors.initials: I
authors.lastname: Image Image
authors.forename: Taisuke
authors.initials: T
authors.lastname: Tomita
authors.forename: Image Image
authors.initials: II
authors.lastname: Image Image
authors.forename: Takeshi
authors.initials: T
authors.lastname: Iwatsubo
authors.forename: Image
authors.initials: I
authors.lastname: Image Image
mesh_terms: D000595:Amino Acid Sequence; D053829:Amyloid Precursor Protein Secretases / Q000235:genetics / Q000378:metabolism*; D016282:Aspartic Acid Endopeptidases / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites / Q000235:genetics; D002460:Cell Line; D005816:Genetic Complementation Test; D005822:Genetic Vectors / Q000235:genetics; D006801:Humans; D015151:Immunoblotting; D008969:Molecular Sequence Data; D009154:Mutation; D019920:Photoaffinity Labels; D053764:Presenilin-1 / Q000235:genetics / Q000378:metabolism*; D012190:Retroviridae / Q000235:genetics; D013379:Substrate Specificity; D014161:Transduction, Genetic
chemical_list: D019920:Photoaffinity Labels; D053764:Presenilin-1; D053829:Amyloid Precursor Protein Secretases; D016282:Aspartic Acid Endopeptidases; C509280:BACE1 protein, human