title: Apolipoprotein E receptor 2 interactions with the N-methyl-D-aspartate receptor.
abstract: In our previous studies we showed that apoE treatment of neurons activated ERK 1/2 signaling, and activation was blocked by treatment with inhibitors of the low density lipoprotein receptor family, the N-methyl-d-aspartate (NMDA) receptor antagonist MK 801, and calcium channel blockers. We hypothesized an interaction between the low density lipoprotein receptor family members and the NMDA receptor. In the present study, we confirmed through co-immunoprecipitation experiments an interaction between the apoE receptor, ApoEr2, and NMDAR1 through their extracellular domains. We also found that the PDZ1 domain of PSD95, a postsynaptic scaffolding protein, interacted with the C terminus of ApoEr2 via an alternatively spliced, intracellular exon. This interaction between ApoEr2 and PSD95 in neurons was modulated by NMDA receptor activation and an ApoEr2 ligand. We also found that the PDZ2 domain of PSD95 interacted with the NR2A and NR2B subunits of NMDA receptors. Full-length PSD95 increased cell surface levels of ApoEr2 and its cleavage, resulting in increases in secreted ApoEr2 and C-terminal fragments of ApoEr2. These studies suggest that ApoEr2 can form a multiprotein complex with NMDA receptor subunits and PSD95.
authors.affiliation: Department of Neuroscience and Physiology, Georgetown University Medical Center, Washington, DC 20057-1464, USA.
authors.forename: Hyang-Sook
authors.initials: HS
authors.lastname: Hoe
authors.forename: Ana
authors.initials: A
authors.lastname: Pocivavsek
authors.forename: Geetanjali
authors.initials: G
authors.lastname: Chakraborty
authors.forename: Zhanyan
authors.initials: Z
authors.lastname: Fu
authors.forename: Stefano
authors.initials: S
authors.lastname: Vicini
authors.forename: Michael D
authors.initials: MD
authors.lastname: Ehlers
authors.forename: G William
authors.initials: GW
authors.lastname: Rebeck
mesh_terms: D017398:Alternative Splicing; D000818:Animals; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism; D019556:COS Cells; D015220:Calcium Channels / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D003593:Cytoplasm / Q000378:metabolism; D000076122:Disks Large Homolog 4 Protein; D016291:Dizocilpine Maleate / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005091:Exons; D005822:Genetic Vectors; D051528:Guanylate Kinases; D006801:Humans; D047468:Immunoprecipitation; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry; D008024:Ligands; D026503:Low Density Lipoprotein Receptor-Related Protein-1 / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry; D051379:Mice; D008954:Models, Biological; D015233:Models, Statistical; D009474:Neurons / Q000378:metabolism; D009995:Osmosis; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011973:Receptors, LDL / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism*; D014162:Transfection; D020798:Two-Hybrid System Techniques
chemical_list: D015220:Calcium Channels; D000076122:Disks Large Homolog 4 Protein; C501447:Dlg4 protein, mouse; D018691:Excitatory Amino Acid Antagonists; D047908:Intracellular Signaling Peptides and Proteins; D008024:Ligands; D026503:Low Density Lipoprotein Receptor-Related Protein-1; D008565:Membrane Proteins; D011973:Receptors, LDL; D016194:Receptors, N-Methyl-D-Aspartate; D016291:Dizocilpine Maleate; D051528:Guanylate Kinases