title: Afadin regulates puncta adherentia junction formation and presynaptic differentiation in hippocampal neurons.
abstract: The formation and remodeling of mossy fiber-CA3 pyramidal cell synapses in the stratum lucidum of the hippocampus are implicated in the cellular basis of learning and memory. Afadin and its binding cell adhesion molecules, nectin-1 and nectin-3, together with N-cadherin, are concentrated at puncta adherentia junctions (PAJs) in these synapses. Here, we investigated the roles of afadin in PAJ formation and presynaptic differentiation in mossy fiber-CA3 pyramidal cell synapses. At these synapses in the mice in which the afadin gene was conditionally inactivated before synaptogenesis by using nestin-Cre mice, the immunofluorescence signals for the PAJ components, nectin-1, nectin-3 and N-cadherin, disappeared almost completely, while those for the presynaptic components, VGLUT1 and bassoon, were markedly decreased. In addition, these signals were significantly decreased in cultured afadin-deficient hippocampal neurons. Furthermore, the interevent interval of miniature excitatory postsynaptic currents was prolonged in the cultured afadin-deficient hippocampal neurons compared with control neurons, indicating that presynaptic functions were suppressed or a number of synapse was reduced in the afadin-deficient neurons. Analyses of presynaptic vesicle recycling and paired recordings revealed that the cultured afadin-deficient neurons showed impaired presynaptic functions. These results indicate that afadin regulates both PAJ formation and presynaptic differentiation in most mossy fiber-CA3 pyramidal cell synapses, while in a considerable population of these neurons, afadin regulates only PAJ formation but not presynaptic differentiation.
authors.affiliation: Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan ; CREST, Japan Science and Technology Agency, Kobe, Hyogo, Japan.
authors.forename: Daisaku
authors.initials: D
authors.lastname: Toyoshima
authors.affiliation: Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan ; CREST, Japan Science and Technology Agency, Kobe, Hyogo, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Mandai
authors.affiliation: Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan ; CREST, Japan Science and Technology Agency, Kobe, Hyogo, Japan.
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Maruo
authors.affiliation: Faculty of Health Sciences, Kobe University Graduate School of Health Sciences, Kobe, Hyogo, Japan ; CREST, Japan Science and Technology Agency, Kobe, Hyogo, Japan.
authors.forename: Irwan
authors.initials: I
authors.lastname: Supriyanto
authors.affiliation: Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan ; CREST, Japan Science and Technology Agency, Kobe, Hyogo, Japan.
authors.forename: Hideru
authors.initials: H
authors.lastname: Togashi
authors.affiliation: Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan ; CREST, Japan Science and Technology Agency, Kobe, Hyogo, Japan.
authors.forename: Takahito
authors.initials: T
authors.lastname: Inoue
authors.affiliation: Faculty of Health Sciences, Kobe University Graduate School of Health Sciences, Kobe, Hyogo, Japan ; CREST, Japan Science and Technology Agency, Kobe, Hyogo, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Mori
authors.affiliation: Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan ; CREST, Japan Science and Technology Agency, Kobe, Hyogo, Japan.
authors.forename: Yoshimi
authors.initials: Y
authors.lastname: Takai
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism / Q000473:pathology; D015820:Cadherins / Q000378:metabolism; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D008840:Microfilament Proteins / Q000235:genetics / Q000378:metabolism*; D019599:Mossy Fibers, Hippocampal / Q000378:metabolism; D000075983:Nectins; D017729:Presynaptic Terminals / Q000378:metabolism; D017966:Pyramidal Cells / Q000378:metabolism*; D013569:Synapses / Q000378:metabolism*
chemical_list: D015820:Cadherins; D015815:Cell Adhesion Molecules; D008840:Microfilament Proteins; C000619015:Nectin1 protein, mouse; C000619017:Nectin3 protein, mouse; D000075983:Nectins; C108835:afadin