title: FE65 interaction with the ApoE receptor ApoEr2.
abstract: The adaptor protein FE65 interacts with the beta-amyloid precursor protein (APP) via its C-terminal phosphotyrosine binding (PTB) domain and affects APP processing and Abeta production. Our previous data demonstrate that the apoE receptor ApoEr2 co-precipitated with APP and suggest that there are extracellular and intracellular interactions between these two transmembrane proteins. We hypothesized that FE65 acts as an intracellular link between ApoEr2 and APP. Co-immunoprecipitation experiments in COS7 cells demonstrated an interaction between ApoEr2 and FE65 that depended on the N-terminal PTB domain of FE65. Full-length FE65 increased co-immunoprecipitation of ApoEr2 and APP. Full-length FE65 also increased surface expression of ApoEr2, as determined by surface protein biotinylation and live cell surface staining. Constructs containing both the C- and N-terminal PTB domains of FE65 increased secreted APP, secreted ApoEr2, APP C-terminal fragment, and ApoEr2 C-terminal fragment, but constructs containing only single PTB domains did not affect APP or ApoEr2 processing. In addition, full-length FE65 decreased Abeta to a significantly greater extent than individual FE65 domains. These data suggest that FE65 can bind APP and ApoEr2 at the same time and affect the processing of each.
authors.affiliation: Department of Neuroscience, Georgetown University Medical Center, Washington, D. C. 20057-1464, USA.
authors.forename: Hyang-Sook
authors.initials: HS
authors.lastname: Hoe
authors.forename: Laura Ann
authors.initials: LA
authors.lastname: Magill
authors.forename: Suzanne
authors.initials: S
authors.lastname: Guenette
authors.forename: Zhanyan
authors.initials: Z
authors.lastname: Fu
authors.forename: Stefano
authors.initials: S
authors.lastname: Vicini
authors.forename: G William
authors.initials: GW
authors.lastname: Rebeck
mesh_terms: D016564:Amyloid beta-Protein Precursor / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites; D002478:Cells, Cultured; D006801:Humans; D026502:LDL-Receptor Related Proteins; D051379:Mice; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism; D009687:Nuclear Proteins / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D018110:Receptors, Lipoprotein / Q000737:chemistry / Q000378:metabolism*
chemical_list: D016564:Amyloid beta-Protein Precursor; C486243:Apbb1 protein, mouse; D026502:LDL-Receptor Related Proteins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D018110:Receptors, Lipoprotein; C098773:low density lipoprotein receptor-related protein 8