title: Transport along the dendritic endoplasmic reticulum mediates the trafficking of GABAB receptors.
abstract: In neurons, secretory organelles within the cell body are complemented by the dendritic endoplasmic reticulum (ER) and Golgi outposts (GOPs), whose role in neurotransmitter receptor trafficking is poorly understood. γ-aminobutyric acid (GABA) type B metabotropic receptors (GABABRs) regulate the efficacy of synaptic transmission throughout the brain. Their plasma membrane availability is controlled by mechanisms involving an ER retention motif and assembly-dependent ER export. Thus, they constitute an ideal molecular model to study ER trafficking, but the extent to which the dendritic ER participates in GABABR biosynthesis has not been thoroughly explored. Here, we show that GABAB1 localizes preferentially to the ER in dendrites and moves long distances within this compartment. Not only diffusion but also microtubule and dynein-dependent mechanisms control dendritic ER transport. GABABRs insert throughout the somatodendritic plasma membrane but dendritic post-ER carriers containing GABABRs do not fuse selectively with GOPs. This study furthers our understanding of the spatial selectivity of neurotransmitter receptors for dendritic organelles.
authors.affiliation: Program of Physiology and Biophysics, ICBM, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile Biomedical Neuroscience Institute, BNI, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile.
authors.forename: José I
authors.initials: JI
authors.lastname: Valenzuela
authors.affiliation: Program of Physiology and Biophysics, ICBM, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile Biomedical Neuroscience Institute, BNI, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile.
authors.forename: Matías
authors.initials: M
authors.lastname: Jaureguiberry-Bravo
authors.affiliation: Program of Physiology and Biophysics, ICBM, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile Biomedical Neuroscience Institute, BNI, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile.
authors.forename: Daniela A
authors.initials: DA
authors.lastname: Salas
authors.affiliation: Program of Physiology and Biophysics, ICBM, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile Biomedical Neuroscience Institute, BNI, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile Program of Anatomy and Development, ICBM, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile.
authors.forename: Omar A
authors.initials: OA
authors.lastname: Ramírez
authors.affiliation: Program of Physiology and Biophysics, ICBM, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile Biomedical Neuroscience Institute, BNI, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile.
authors.forename: Víctor H
authors.initials: VH
authors.lastname: Cornejo
authors.affiliation: Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA Program in Molecular Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
authors.forename: Hsiangmin E
authors.initials: HE
authors.lastname: Lu
authors.affiliation: Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Blanpied
authors.affiliation: Program of Physiology and Biophysics, ICBM, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile Biomedical Neuroscience Institute, BNI, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile andres@neuro.med.uchile.cl.
authors.forename: Andrés
authors.initials: A
authors.lastname: Couve
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D003712:Dendrites / Q000378:metabolism* / Q000648:ultrastructure*; D004058:Diffusion; D004398:Dyneins / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D005260:Female; D059330:GABAergic Neurons / Q000378:metabolism* / Q000648:ultrastructure; D051379:Mice; D008822:Mice, Transgenic; D008870:Microtubules / Q000378:metabolism; D020534:Parahippocampal Gyrus / Q000502:physiology*; D021381:Protein Transport; D051381:Rats; D017207:Rats, Sprague-Dawley; D018080:Receptors, GABA-B / Q000235:genetics / Q000378:metabolism*; D009435:Synaptic Transmission; D059008:Time-Lapse Imaging
chemical_list: D018080:Receptors, GABA-B; D004398:Dyneins
keywords: Dendrite; Endoplasmic reticulum; GABA; Golgi outposts; Neuron; Trafficking