title: EFA6A, a guanine nucleotide exchange factor for Arf6, interacts with sorting nexin-1 and regulates neurite outgrowth.
abstract: The membrane trafficking and actin cytoskeleton remodeling mediated by ADP ribosylation factor 6 (Arf6) are functionally linked to various neuronal processes including neurite formation and maintenance, neurotransmitter release, and receptor internalization. EFA6A is an Arf6-specific guanine nucleotide exchange factor that is abundantly expressed in the brain. In this study, we identified sorting nexin-1 (SNX1), a retromer component that is implicated in endosomal sorting and trafficking, as a novel interacting partner for EFA6A by yeast two-hybrid screening. The interaction was mediated by the C-terminal region of EFA6A and a BAR domain of SNX1, and further confirmed by pull-down assay and immunoprecipitation from mouse brain lysates. In situ hybridization analysis demonstrated the widespread expression of SNX1 in the mouse brain, which overlapped with the expression of EFA6A in the forebrain. Immunofluorescent analysis revealed the partial colocalization of EFA6A and SNX1 in the dendritic fields of the hippocampus. Immunoelectron microscopic analysis revealed the overlapping subcellular localization of EFA6A and SNX1 at the post-synaptic density and endosomes in dendritic spines. In Neuro-2a neuroblastoma cells, expression of either EFA6A or SNX1 induced neurite outgrowth, which was further enhanced by co-expression of EFA6A and SNX1. The present findings suggest a novel mechanism by which EFA6A regulates Arf6-mediated neurite formation through the interaction with SNX1.
authors.affiliation: Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Fukaya
authors.forename: Daisuke
authors.initials: D
authors.lastname: Fukushima
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Hara
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Sakagami
mesh_terms: D000089982:ADP-Ribosylation Factor 6; D020727:ADP-Ribosylation Factors / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D020662:Guanine Nucleotide Exchange Factors / Q000378:metabolism*; D006168:Guinea Pigs; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D016501:Neurites / Q000502:physiology* / Q000648:ultrastructure; D011485:Protein Binding / Q000502:physiology; D011817:Rabbits; D058305:Sorting Nexins / Q000378:metabolism*
chemical_list: D000089982:ADP-Ribosylation Factor 6; D020662:Guanine Nucleotide Exchange Factors; D009419:Nerve Tissue Proteins; C109970:PSD protein, human; C505835:SNX1 protein, mouse; D058305:Sorting Nexins; D020727:ADP-Ribosylation Factors; C000715348:ARF6 protein, human; C000715727:Arf6 protein, mouse
keywords: ADP ribosylation factor; dendritic spine; guanine nucleotide exchange factor; membrane traffic; post-synaptic density