Weak effect of membrane diffusion on the rate of receptor accumulation at adhesive contacts
Biophysical Journal. 2005-11-01; 89(5): L40-L42
DOI: 10.1529/biophysj.105.071688
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1. Biophys J. 2005 Nov;89(5):L40-2. Epub 2005 Sep 16.
Weak effect of membrane diffusion on the rate of receptor accumulation at
adhesive contacts.
Thoumine O(1), Saint-Michel E, Dequidt C, Falk J, Rudge R, Galli T,
Faivre-Sarrailh C, Choquet D.
Author information:
(1)CNRS 5091, Université Bordeaux 2, Bordeaux, France.
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.
DOI: 10.1529/biophysj.105.071688
PMCID: PMC1366862
PMID: 16169990 [Indexed for MEDLINE]