title: Colocalization of APC and PSD-95 in the nerve fiber as well as in the post-synapse of matured neurons.
abstract: Adenomatous polyposis coli protein (APC) is highly expressed in the nervous tissue, but its function there is not yet known. We previously found that the microtubule-bundling activity of APC is stimulated by its interaction with PSD-95, a neuronal scaffolding protein, in cultured COS-7 cells. In the present study, we investigated the distribution and localization of the intrinsic APC and PSD-95 in both cultured rat hippocampal neurons and in the rat cerebellum by immunofluorescence and immunoelectron microscopy. In cultured neurons, most of the PSD-95 immunofluorescence puncta were colocalized with APC, and the APC and PSD-95 immunogolds were colocalized in the nerve fibers as well as in the postsynaptic site, but not in the presynaptic site. In the molecular layer of the rat cerebellum, colocalization of APC and PSD-95 was also detected in the nerve fibers and the postsynaptic site, but not in the presynaptic site. Based on these results, we conclude that APC and PSD-95 colocalize and bind to form a protein complex in nerve fibers as well as in postsynaptic sites in matured neurons, suggesting the involvement of the APC/PSD-95 complex in the microtubule functions within the nerve fibers and the synapse functions at the postsynaptic site.
authors.affiliation: Department of Anatomy I, Fujita Health University School of Medicine, Aichi, Japan.
authors.forename: Takanori
authors.initials: T
authors.lastname: Onouchi
authors.forename: Nobutaka
authors.initials: N
authors.lastname: Takamori
authors.forename: Takao
authors.initials: T
authors.lastname: Senda
mesh_terms: D025601:Adenomatous Polyposis Coli Protein / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D002531:Cerebellum / Q000378:metabolism; D000076122:Disks Large Homolog 4 Protein; D006624:Hippocampus / Q000166:cytology; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D016253:Microscopy, Immunoelectron; D009412:Nerve Fibers / Q000378:metabolism; D009474:Neurons / Q000378:metabolism* / Q000502:physiology; D051381:Rats; D013569:Synapses / Q000378:metabolism*
chemical_list: D025601:Adenomatous Polyposis Coli Protein; D000076122:Disks Large Homolog 4 Protein; C501449:Dlg4 protein, rat; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins