title: Distinct subcellular localization of alternative splicing variants of EFA6D, a guanine nucleotide exchange factor for Arf6, in the mouse brain.
abstract: EFA6D (guanine nucleotide exchange factor for ADP-ribosylation factor 6 [Arf6]D) is also known as EFA6R, Psd3, and HCA67. It is the fourth member of the EFA6 family with guanine nucleotide exchange activity for Arf6, a small guanosine triphosphatase (GTPase) that regulates endosomal trafficking and actin cytoskeleton remodeling. We propose a classification and nomenclature of 10 EFA6D variants deposited in the GenBank database as EFA6D1a, 1b, 1c, 1d, 1s, 2a, 2b, 2c, 2d, and 2s based on the combination of N-terminal and C-terminal insertions. Polymerase chain reaction analysis showed the expression of all EFA6D variants except for variants a and d in the adult mouse brain. Immunoblotting analysis with novel variant-specific antibodies showed the endogenous expression of EFA6D1b, EFA6D1c, and EFA6D1s at the protein level, with the highest expression being EFA6D1s, in the brain. Immunoblotting analysis of forebrain subcellular fractions showed the distinct subcellular distribution of EFA6D1b/c and EFA6D1s. The immunohistochemical analysis revealed distinct but overlapping immunoreactive patterns between EFA6D1b/c and EFA6D1s in the mouse brain. In immunoelectron microscopic analyses of the hippocampal CA3 region, EFA6D1b/c was present predominantly in the mossy fiber axons of dentate granule cells, whereas EFA6D1s was present abundantly in the cell bodies, dendritic shafts, and spines of hippocampal pyramidal cells. These results provide the first anatomical evidence suggesting the functional diversity of EFA6D variants, particularly EFA6D1b/c and EFA6D1s, in neurons. J. Comp. Neurol. 524:2531-2552, 2016. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa, 252-0374, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Fukaya
authors.affiliation: Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa, 252-0374, Japan.
authors.forename: Shingo
authors.initials: S
authors.lastname: Ohta
authors.affiliation: Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa, 252-0374, Japan.
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Hara
authors.affiliation: Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa, 252-0374, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Tamaki
authors.affiliation: Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa, 252-0374, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Sakagami
mesh_terms: D000089982:ADP-Ribosylation Factor 6; D020727:ADP-Ribosylation Factors / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics; D017398:Alternative Splicing / Q000502:physiology*; D000818:Animals; D001921:Brain / Q000166:cytology / Q000378:metabolism*; D001923:Brain Chemistry / Q000502:physiology; D014644:Genetic Variation / Q000502:physiology*; D020662:Guanine Nucleotide Exchange Factors / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics; D006168:Guinea Pigs; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D011817:Rabbits; D013347:Subcellular Fractions / Q000737:chemistry / Q000378:metabolism
chemical_list: D000089982:ADP-Ribosylation Factor 6; D020662:Guanine Nucleotide Exchange Factors; C504474:Psd protein, mouse; D020727:ADP-Ribosylation Factors; C000715727:Arf6 protein, mouse
keywords: ADP-ribosylation factor; RRID: AB_2315558: RRID: AB_2571560; RRID: AB_2532104; RRID: AB_2571540; RRID: AB_2571556; RRID: AB_2571557; RRID: AB_2571558; RRID: AB_262044; RRID: AB_443473; RRID: AB_839504; RRID: AB_94944; alternative splicing; axon; dendritic spine; guanine nucleotide exchange factor; membrane traffic