title: Protein interactions among Fe65, the low-density lipoprotein receptor-related protein, and the amyloid precursor protein.
abstract: The adapter protein Fe65 has been proposed to be the link between the intracellular domains of the amyloid precursor protein, APP (AICD), and the low-density lipoprotein receptor-related protein (LRP-CT). Functional linkage between these two proteins has been established, and mutations within LRP-CT affect the amount of Aβ produced from APP. Previous work showed that AICD binds to protein interaction domain 2 (PID2) of Fe65. Although the structure of PID1 was determined recently, all attempts to demonstrate LRP-CT binding to this domain failed. We used biophysical experiments and binding studies to investigate the binding among these three proteins. Full-length Fe65 bound more weakly to AICD than did N-terminally truncated forms; however, the intramolecular domain-domain interactions that had been proposed to inhibit binding could not be observed using amide H-D exchange. Surprisingly, when LRP-CT is phosphorylated at Tyr4507, it bound to Fe65 PID1 despite the fact that this domain belongs to the Dab-like subclass of PIDs that are not supposed to be phosphorylation-dependent. Mutation of a critical arginine abolished binding, providing further proof of the phosphorylation dependence. Fe65 PID1 thus provides a link between the Dab-like class and the IRS-like class of PIDs and is the first Dab-like family member to show phosphorylation-dependent binding.
authors.affiliation: Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0378, United States.
authors.forename: Melinda M
authors.initials: MM
authors.lastname: Mulvihill
authors.forename: Miklos
authors.initials: M
authors.lastname: Guttman
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Komives
mesh_terms: D000595:Amino Acid Sequence; D016564:Amyloid beta-Protein Precursor / Q000737:chemistry* / Q000378:metabolism; D001667:Binding, Competitive; D018360:Crystallography, X-Ray; D006801:Humans; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000737:chemistry* / Q000378:metabolism; D009687:Nuclear Proteins / Q000737:chemistry* / Q000378:metabolism; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D025941:Protein Interaction Mapping; D017434:Protein Structure, Tertiary; D011973:Receptors, LDL / Q000737:chemistry* / Q000378:metabolism
chemical_list: C091042:APBB1 protein, human; C489697:APLP1 protein, human; D016564:Amyloid beta-Protein Precursor; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D011973:Receptors, LDL; D019000:Phosphotyrosine