Weak Effect of Membrane Diffusion on the Rate of Receptor Accumulation at Adhesive Contacts.


  • Thoumine Olivier
  • Saint-Michel Edouard
  • Dequidt Caroline
  • Falk Julien
  • Rudge Rachel
  • Galli Thierry
  • Faivre-Sarrailh Catherine
  • Choquet Daniel


  • Receptor
  • Adhesion
  • Membrane
  • Diffusion
  • Kinetics

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To assess if membrane diffusion could affect the kinetics of receptor recruitment at adhesive contacts, we transfected neurons with GFP-tagged IgCAMs 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 µm2/s), and was inversely proportional to the size of the receptor. We then triggered adhesive contact formation by placing anti-GFP 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 IgCAMs is not a limiting step in the initiation of neuronal contacts.

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