title: Localization of mature neprilysin in lipid rafts.
abstract: Alzheimer's disease (AD) is characterized by senile plaques caused by amyloid-β peptide (Aβ) accumulation. It has been reported that Aβ generation and accumulation occur in membrane microdomains, called lipid rafts, which are enriched in cholesterol and glycosphingolipids. Moreover, the ablation of cholesterol metabolism has been implicated in AD. Neprilysin (NEP), a neutral endopeptidase, is one of the major Aβ-degrading enzymes in the brain. Activation of NEP is a possible therapeutic target. However, it remains unknown whether the activity of NEP is regulated by its association with lipid rafts. Here we show that only the mature form of NEP, which has been glycosylated in the Golgi, exists in lipid rafts, where it is directly associated with phosphatidylserine. Moreover, the localization of NEP in lipid rafts is enhanced by its dimerization, as shown using the NEP E403C homodimerization mutant. However, the protease activities of the mature form of NEP, as assessed by in vitro peptide hydrolysis, did not differ between lipid rafts and nonlipid rafts. We conclude that cholesterol and other lipids regulate the localization of mature NEP to lipid rafts, where the substrate Aβ accumulates but does not modulate the protease activity of NEP.
authors.affiliation: Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan.
authors.forename: Kimihiko
authors.initials: K
authors.lastname: Sato
authors.forename: Chiaki
authors.initials: C
authors.lastname: Tanabe
authors.forename: Yoji
authors.initials: Y
authors.lastname: Yonemura
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Watahiki
authors.forename: Yimeng
authors.initials: Y
authors.lastname: Zhao
authors.forename: Sosuke
authors.initials: S
authors.lastname: Yagishita
authors.forename: Maiko
authors.initials: M
authors.lastname: Ebina
authors.forename: Satoshi
authors.initials: S
authors.lastname: Suo
authors.forename: Eugene
authors.initials: E
authors.lastname: Futai
authors.forename: Masayuki
authors.initials: M
authors.lastname: Murata
authors.forename: Shoichi
authors.initials: S
authors.lastname: Ishiura
mesh_terms: D016229:Amyloid beta-Peptides / Q000378:metabolism; D002461:Cell Line, Transformed; D002784:Cholesterol / Q000378:metabolism; D019281:Dimerization; D010450:Endopeptidases / Q000378:metabolism; D006801:Humans; D021962:Membrane Microdomains / Q000737:chemistry / Q000201:enzymology* / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D015260:Neprilysin / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D047392:beta-Cyclodextrins / Q000494:pharmacology
chemical_list: D016229:Amyloid beta-Peptides; D047392:beta-Cyclodextrins; C108732:methyl-beta-cyclodextrin; D002784:Cholesterol; D010450:Endopeptidases; D015260:Neprilysin