QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

Vol. 17, Issue 2, 862-875, February 2006

This Article Full Text Full Text (PDF) All Versions of this Article: E05-04-0335v1 17/2/862    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Thoumine, O. Articles by Choquet, D. Search for Related Content PubMed PubMed Citation Articles by Thoumine, O. Articles by Choquet, D.

Regulation of N-Cadherin Dynamics at Neuronal Contacts by Ligand Binding and Cytoskeletal Coupling

Olivier Thoumine ^*, Mireille Lambert , René-Marc Mège , and Daniel Choquet ^*

^* CNRS, UMR 5091, Institut Magendie de Neurosciences, Université Bordeaux 2, 33077 Bordeaux, France; INSERM, U706, Institut du Fer à Moulin, Université Pierre et Marie Curie, 75005 Paris, France

Submitted April 21, 2005; Revised October 7, 2005; Accepted November 18, 2005
Monitoring Editor: Asma Nusrat

N-cadherin plays a key role in axonal outgrowth and synaptogenesis, but how neurons initiate and remodel N-cadherin-based adhesions remains unclear. We addressed this issue with a semiartificial system consisting of N-cadherin coated microspheres adhering to cultured neurons transfected for N-cadherin-GFP. Using optical tweezers, we show that growth cones are particularly reactive to N-cadherin coated microspheres, which they capture in a few seconds and drag rearward. Such strong coupling requires an intact connection between N-cadherin receptors and catenins. As they move to the basis of growth cones, microspheres slow down while gradually accumulating N-cadherin-GFP, demonstrating a clear delay between bead coupling to the actin flow and receptor recruitment. Using FRAP and photoactivation, N-cadherin receptors at bead-to-cell contacts were found to continuously recycle, consistently with a model of ligand-receptor reaction not limited by membrane diffusion. The use of N-cadherin-GFP receptors truncated or mutated in specific cytoplasmic regions show that N-cadherin turnover is exquisitely regulated by catenin partners. Turnover rates are considerably lower than those obtained previously in single molecule studies, demonstrating an active regulation of cadherin bond kinetics in intact cells. Finally, spontaneous neuronal contacts enriched in N-cadherin exhibited similar turnover rates, suggesting that such dynamics of N-cadherin may represent an intrinsic mechanism underlying the plasticity of neuronal adhesions.

Abbreviations used: DIV, days in vitro; CytD, cytochalasin D; FRAP, fluorescence recovery after photobleaching; Ncad-Fc, N-cadherin fused to Fc; Ncad-GFP, N-cadherin fused to GFP; Noc, nocodazole; PAGFP, photoactivatable GFP.

Address correspondence to: Olivier Thoumine (olivier.thoumine{at}pcs.u-bordeaux2.fr) or Daniel Choquet (daniel.choquet{at}pcs.u-bordeaux2.fr).

This article has been cited by other articles:

				M. Heine, O. Thoumine, M. Mondin, B. Tessier, G. Giannone, and D. Choquet Activity-independent and subunit-specific recruitment of functional AMPA receptors at neurexin/neuroligin contacts PNAS, December 30, 2008; 105(52): 20947 - 20952. [Abstract] [Full Text] [PDF]

				L. Bard, C. Boscher, M. Lambert, R.-M. Mege, D. Choquet, and O. Thoumine A Molecular Clutch between the Actin Flow and N-Cadherin Adhesions Drives Growth Cone Migration J. Neurosci., June 4, 2008; 28(23): 5879 - 5890. [Abstract] [Full Text] [PDF]

				C. Dequidt, L. Danglot, P. Alberts, T. Galli, D. Choquet, and O. Thoumine Fast Turnover of L1 Adhesions in Neuronal Growth Cones Involving Both Surface Diffusion and Exo/Endocytosis of L1 Molecules Mol. Biol. Cell, August 1, 2007; 18(8): 3131 - 3143. [Abstract] [Full Text] [PDF]