Weak effect of membrane diffusion on the rate of receptor accumulation at adhesive contacts

Biophys J. 2005 Nov;89(5):L40-2. doi: 10.1529/biophysj.105.071688. Epub 2005 Sep 16.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biophysics / methods*
  • Cell Adhesion
  • Cell Adhesion Molecules / chemistry
  • Cell Membrane* / metabolism
  • Cells, Cultured
  • Diffusion
  • Green Fluorescent Proteins / chemistry
  • Green Fluorescent Proteins / metabolism
  • Hippocampus / metabolism
  • Immunoglobulins / chemistry
  • Kinetics
  • Microscopy, Fluorescence
  • Molecular Weight
  • Neurons / metabolism*
  • Protein Binding
  • Rats
  • Time Factors
  • Transfection


  • Cell Adhesion Molecules
  • Immunoglobulins
  • NrCAM protein, rat
  • Green Fluorescent Proteins