title: Confined diffusion without fences of a g-protein-coupled receptor as revealed by single particle tracking.
abstract: Single particle tracking is a powerful tool for probing the organization and dynamics of the plasma membrane constituents. We used this technique to study the micro -opioid receptor belonging to the large family of the G-protein-coupled receptors involved with other partners in a signal transduction pathway. The specific labeling of the receptor coupled to a T7-tag at its N-terminus, stably expressed in fibroblastic cells, was achieved by colloidal gold coupled to a monoclonal anti T7-tag antibody. The lateral movements of the particles were followed by nanovideomicroscopy at 40 ms time resolution during 2 min with a spatial precision of 15 nm. The receptors were found to have either a slow or directed diffusion mode (10%) or a walking confined diffusion mode (90%) composed of a long-term random diffusion and a short-term confined diffusion, and corresponding to a diffusion confined within a domain that itself diffuses. The results indicate that the confinement is due to an effective harmonic potential generated by long-range attraction between the membrane proteins. A simple model for interacting membrane proteins diffusion is proposed that explains the variations with the domain size of the short-term and long-term diffusion coefficients.
authors.affiliation: Institut de Pharmacologie et Biologie Structurale, CNRS UMR 5089, 205, route de Narbonne, 31077 Toulouse Cedex, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Daumas
authors.forename: Nicolas
authors.initials: N
authors.lastname: Destainville
authors.forename: Claire
authors.initials: C
authors.lastname: Millot
authors.forename: André
authors.initials: A
authors.lastname: Lopez
authors.forename: David
authors.initials: D
authors.lastname: Dean
authors.forename: Laurence
authors.initials: L
authors.lastname: Salomé
mesh_terms: D017123:Bacteriophage T7 / Q000737:chemistry; D002460:Cell Line; D002462:Cell Membrane / Q000737:chemistry / Q000502:physiology / Q000648:ultrastructure*; D004058:Diffusion; D005347:Fibroblasts / Q000737:chemistry / Q000502:physiology / Q000648:ultrastructure; D020555:GTP-Binding Protein Regulators / Q000737:chemistry / Q000502:physiology / Q000648:ultrastructure; D019204:GTP-Binding Proteins / Q000737:chemistry / Q000502:physiology / Q000648:ultrastructure; D017979:Gold Colloid / Q000737:chemistry; D007668:Kidney / Q000737:chemistry / Q000502:physiology / Q000648:ultrastructure; D018715:Microscopy, Video / Q000295:instrumentation / Q000379:methods*; D008863:Microspheres; D008954:Models, Biological; D008956:Models, Chemical; D009038:Motion; D036103:Nanotechnology / Q000295:instrumentation / Q000379:methods*; D010316:Particle Size; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000502:physiology / Q000648:ultrastructure; D017450:Receptors, Opioid, mu / Q000737:chemistry* / Q000172:deficiency / Q000502:physiology / Q000648:ultrastructure*; D015398:Signal Transduction / Q000502:physiology; D013194:Staining and Labeling / Q000379:methods
chemical_list: D020555:GTP-Binding Protein Regulators; D017979:Gold Colloid; D011956:Receptors, Cell Surface; D017450:Receptors, Opioid, mu; D019204:GTP-Binding Proteins