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

Olivier Thoumine (1) , Edouard Saint-Michel (1) , Caroline Dequidt (1) , Julien Falk (2) , Rachel Rudge (3) , Thierry Galli (3) , Catherine Faivre-Sarrailh (2) , Daniel Choquet (1)

1 PCS - Physiologie cellulaire de la synapse
2 NICN - Neurobiologie des interactions cellulaires et neurophysiopathologie - NICN
3 IJM (UMR_7592) - Institut Jacques Monod

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.

Mots clés: Receptor; Adhesion; Membrane; Diffusion; Kinetics

Domaines: Interactions cellulaires [q-bio.CB]

Olivier Thoumine, Edouard Saint-Michel, Caroline Dequidt, Julien Falk, Rachel Rudge, et al.. Weak Effect of Membrane Diffusion on the Rate of Receptor Accumulation at Adhesive Contacts.. Biophysical Journal, 2005, 89(5), pp.L40-42. ⟨10.1529/biophysj.105.071688⟩. ⟨hal-00009552⟩