title: Biochemical and morphological characterization of MAGI-1 in neuronal tissue.
abstract: The membrane-associated guanylate kinase with inverted organization (MAGI) proteins consist of three members, MAGI-1, MAGI-2 (also known as S-SCAM), and MAGI-3. Although MAGI-2 has been analyzed and shown to interact with a variety of postsynaptic proteins, functional analyses and characterization of MAGI-1 in neuronal tissues have been rare. In this study, we prepared a specific antibody against MAGI-1, anti-MAGI-1, and carried out biochemical and morphological analyses of MAGI-1 in rat neuronal tissues. By Western blotting, a high level of MAGI-1 was detected in nervous tissues, especially in olfactory bulb. Biochemical fractionation clarified that MAGI-1 was relatively enriched in the synaptosomal vesicle and synaptic plasma membrane fractions, whereas MAGI-2 and MAGI-3 appeared to be in the synaptic plasma membrane and postsynaptic density fractions. Immunofluorescent analyses revealed diffuse distribution of MAGI-1 in the cell body and processes of primary cultured rat hippocampal neurons, whereas MAGI-2 and MAGI-3 were likely to be enriched at synapses. Immunohistochemical analyses demonstrated that MAGI-1 was expressed in Purkinje cells, in hypocampal neurons in CA1 region, in the glomerulus region of olfactory bulb, and at the dorsal root entry zone in embryonic rat spinal cord. These results suggest neuronal roles of MAGI-1 different from those of MAGI-2/3.
authors.affiliation: Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Human Service Center, Kasugai, Japan.
authors.forename: Hidenori
authors.initials: H
authors.lastname: Ito
authors.forename: Rika
authors.initials: R
authors.lastname: Morishita
authors.forename: Kaori
authors.initials: K
authors.lastname: Sudo
authors.forename: Yoshiaki V
authors.initials: YV
authors.lastname: Nishimura
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Inaguma
authors.forename: Ikuko
authors.initials: I
authors.lastname: Iwamoto
authors.forename: Koh-Ichi
authors.initials: K
authors.lastname: Nagata
mesh_terms: D000818:Animals; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D051528:Guanylate Kinases / Q000378:metabolism*; D007150:Immunohistochemistry; D008565:Membrane Proteins / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D051381:Rats; D013116:Spinal Cord / Q000378:metabolism*; D013569:Synapses / Q000378:metabolism; D013574:Synaptosomes / Q000378:metabolism; D014162:Transfection
chemical_list: D008565:Membrane Proteins; D051528:Guanylate Kinases; C508141:Magi1 protein, rat