title: Role of numb in dendritic spine development with a Cdc42 GEF intersectin and EphB2.
abstract: Numb has been implicated in cortical neurogenesis during nervous system development, as a result of its asymmetric partitioning and antagonizing Notch signaling. Recent studies have revealed that Numb functions in clathrin-dependent endocytosis by binding to the AP-2 complex. Numb is also expressed in postmitotic neurons and plays a role in axonal growth. However, the functions of Numb in later stages of neuronal development remain unknown. Here, we report that Numb specifically localizes to dendritic spines in cultured hippocampal neurons and is implicated in dendritic spine morphogenesis, partially through the direct interaction with intersectin, a Cdc42 guanine nucleotide exchange factor (GEF). Intersectin functions as a multidomain adaptor for proteins involved in endocytosis and cytoskeletal regulation. Numb enhanced the GEF activity of intersectin toward Cdc42 in vivo. Expression of Numb or intersectin caused the elongation of spine neck, whereas knockdown of Numb and Numb-like decreased the protrusion density and its length. Furthermore, Numb formed a complex with EphB2 receptor-type tyrosine kinase and NMDA-type glutamate receptors. Knockdown of Numb suppressed the ephrin-B1-induced spine development and maturation. These results highlight a role of Numb for dendritic spine development and synaptic functions with intersectin and EphB2.
authors.affiliation: Department of Cell Pharmacology, Graduate School of Medicine, Nagoya University, Nagoya, Aichi 466-8550, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Nishimura
authors.forename: Tomoya
authors.initials: T
authors.lastname: Yamaguchi
authors.forename: Akinori
authors.initials: A
authors.lastname: Tokunaga
authors.forename: Akitoshi
authors.initials: A
authors.lastname: Hara
authors.forename: Tomonari
authors.initials: T
authors.lastname: Hamaguchi
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Kato
authors.forename: Akihiro
authors.initials: A
authors.lastname: Iwamatsu
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Okano
authors.forename: Kozo
authors.initials: K
authors.lastname: Kaibuchi
mesh_terms: D033942:Adaptor Proteins, Vesicular Transport / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D019556:COS Cells; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D049229:Dendritic Spines / Q000378:metabolism*; D020662:Guanine Nucleotide Exchange Factors / Q000378:metabolism*; D006624:Hippocampus / Q000166:cytology; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D009024:Morphogenesis; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000378:metabolism*; D009474:Neurons / Q000166:cytology; D011485:Protein Binding; D025941:Protein Interaction Mapping; D021381:Protein Transport; D034741:RNA, Small Interfering / Q000235:genetics; D051381:Rats; D036183:Receptor, EphB2 / Q000378:metabolism*; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism*
chemical_list: D033942:Adaptor Proteins, Vesicular Transport; D020662:Guanine Nucleotide Exchange Factors; C509776:ITSN2 protein, human; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; C113026:NUMB protein, human; D034741:RNA, Small Interfering; D016194:Receptors, N-Methyl-D-Aspartate; D036183:Receptor, EphB2; D020764:cdc42 GTP-Binding Protein