title: Dynamics of somatostatin type 2A receptor cargoes in living hippocampal neurons.
abstract: Despite the large number of G-protein-coupled receptor (GPCR) types expressed in the CNS, little is known about their dynamics in neuronal cells. Dynamic properties of the somatostatin type 2A receptor were therefore examined in resting conditions and after agonist activation in living hippocampal neurons. Using fluorescence recovery after photobleaching experiments, we found that, in absence of ligand, the sst(2A) receptor is mobile and laterally and rapidly diffuse in neuronal membranes. We then observed by live-cell imaging that, after agonist activation, membrane-associated receptors induce the recruitment of beta-arrestin 1-enhanced green fluorescent protein (EGFP) and beta-arrestin 2-EGFP to the plasma membrane. In addition, beta-arrestin 1-EGFP translocate to the nucleus, suggesting that this protein could serve as a nuclear messenger for the sst(2A) receptor in neurons. Receptors are then recruited to preexisting clathrin coated pits, form clusters that internalize, fuse, and move to a perinuclear compartment that we identified as the trans-Golgi network (TGN), and recycle. Receptor cargoes are transported through a microtubule-dependent process directly from early endosomes/recycling endosomes to the TGN, bypassing the late endosomal compartment. Together, these results provide a comprehensive description of GPCR trafficking in living neurons and provide compelling evidence that GPCR cargoes can recycle through the TGN after endocytosis, a phenomenon that has not been anticipated from studies of non-neuronal cells.
authors.affiliation: Institut National de la Santé et de la Recherche Médicale, Unité 676, 75019 Paris, France.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Lelouvier
authors.forename: Gianluca
authors.initials: G
authors.lastname: Tamagno
authors.forename: Angela M
authors.initials: AM
authors.lastname: Kaindl
authors.forename: Alexandre
authors.initials: A
authors.lastname: Roland
authors.forename: Vincent
authors.initials: V
authors.lastname: Lelievre
authors.forename: Virginia
authors.initials: V
authors.lastname: Le Verche
authors.forename: Catherine
authors.initials: C
authors.lastname: Loudes
authors.forename: Pierre
authors.initials: P
authors.lastname: Gressens
authors.forename: Annie
authors.initials: A
authors.lastname: Faivre-Baumann
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Lenkei
authors.forename: Pascal
authors.initials: P
authors.lastname: Dournaud
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D004058:Diffusion; D006624:Hippocampus / Q000166:cytology / Q000378:metabolism* / Q000502:physiology; D006801:Humans; D051379:Mice; D009474:Neurons / Q000166:cytology / Q000378:metabolism* / Q000502:physiology; D021381:Protein Transport / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017481:Receptors, Somatostatin / Q000378:metabolism* / Q000502:physiology
chemical_list: D017481:Receptors, Somatostatin; C093733:somatostatin receptor 2