title: Weak effect of membrane diffusion on the rate of receptor accumulation at adhesive contacts.
abstract: To assess if membrane diffusion could affect the kinetics of receptor recruitment at adhesive contacts, we transfected neurons with green fluorescent protein-tagged immunoglobin cell adhesion molecules of varying length (25-180 kD), and measured the lateral mobility of single quantum dots bound to those receptors at the cell surface. The diffusion coefficient varied within a physiological range (0.1-0.5 microm(2)/s), and was inversely proportional to the size of the receptor. We then triggered adhesive contact formation by placing anti-green fluorescent protein-coated microspheres on growth cones using optical tweezers, and measured surface receptor recruitment around microspheres by time-lapse fluorescence imaging. The accumulation rate was rather insensitive to the type of receptor, suggesting that the long-range membrane diffusion of immunoglobin cell adhesion molecules is not a limiting step in the initiation of neuronal contacts.
authors.affiliation: CNRS 5091, Université Bordeaux 2, Bordeaux, France. olivier.thoumine@pcs.u-bordeaux2.fr
authors.forename: Olivier
authors.initials: O
authors.lastname: Thoumine
authors.forename: Edouard
authors.initials: E
authors.lastname: Saint-Michel
authors.forename: Caroline
authors.initials: C
authors.lastname: Dequidt
authors.forename: Julien
authors.initials: J
authors.lastname: Falk
authors.forename: Rachel
authors.initials: R
authors.lastname: Rudge
authors.forename: Thierry
authors.initials: T
authors.lastname: Galli
authors.forename: Catherine
authors.initials: C
authors.lastname: Faivre-Sarrailh
authors.forename: Daniel
authors.initials: D
authors.lastname: Choquet
mesh_terms: D000818:Animals; D001703:Biophysics / Q000379:methods*; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000737:chemistry; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D004058:Diffusion; D049452:Green Fluorescent Proteins / Q000737:chemistry / Q000378:metabolism; D006624:Hippocampus / Q000378:metabolism; D007136:Immunoglobulins / Q000737:chemistry; D007700:Kinetics; D008856:Microscopy, Fluorescence; D008970:Molecular Weight; D009474:Neurons / Q000378:metabolism*; D011485:Protein Binding; D051381:Rats; D013997:Time Factors; D014162:Transfection
chemical_list: D015815:Cell Adhesion Molecules; D007136:Immunoglobulins; C504754:NrCAM protein, rat; D049452:Green Fluorescent Proteins