Confined diffusion without fences of a g-protein-coupled receptor as revealed by single particle tracking

Biophys J. 2003 Jan;84(1):356-66. doi: 10.1016/S0006-3495(03)74856-5.


Single particle tracking is a powerful tool for probing the organization and dynamics of the plasma membrane constituents. We used this technique to study the micro -opioid receptor belonging to the large family of the G-protein-coupled receptors involved with other partners in a signal transduction pathway. The specific labeling of the receptor coupled to a T7-tag at its N-terminus, stably expressed in fibroblastic cells, was achieved by colloidal gold coupled to a monoclonal anti T7-tag antibody. The lateral movements of the particles were followed by nanovideomicroscopy at 40 ms time resolution during 2 min with a spatial precision of 15 nm. The receptors were found to have either a slow or directed diffusion mode (10%) or a walking confined diffusion mode (90%) composed of a long-term random diffusion and a short-term confined diffusion, and corresponding to a diffusion confined within a domain that itself diffuses. The results indicate that the confinement is due to an effective harmonic potential generated by long-range attraction between the membrane proteins. A simple model for interacting membrane proteins diffusion is proposed that explains the variations with the domain size of the short-term and long-term diffusion coefficients.

Publication types

  • Comparative Study
  • Evaluation Study
  • Research Support, Non-U.S. Gov't
  • Validation Study

MeSH terms

  • Bacteriophage T7 / chemistry
  • Cell Line
  • Cell Membrane / chemistry
  • Cell Membrane / physiology
  • Cell Membrane / ultrastructure*
  • Diffusion
  • Fibroblasts / chemistry
  • Fibroblasts / physiology
  • Fibroblasts / ultrastructure
  • GTP-Binding Protein Regulators / chemistry
  • GTP-Binding Protein Regulators / physiology
  • GTP-Binding Protein Regulators / ultrastructure
  • GTP-Binding Proteins / chemistry
  • GTP-Binding Proteins / physiology
  • GTP-Binding Proteins / ultrastructure
  • Gold Colloid / chemistry
  • Kidney / chemistry
  • Kidney / physiology
  • Kidney / ultrastructure
  • Microscopy, Video / instrumentation
  • Microscopy, Video / methods*
  • Microspheres
  • Models, Biological
  • Models, Chemical
  • Motion*
  • Nanotechnology / instrumentation
  • Nanotechnology / methods*
  • Particle Size
  • Receptors, Cell Surface / chemistry
  • Receptors, Cell Surface / physiology
  • Receptors, Cell Surface / ultrastructure
  • Receptors, Opioid, mu / chemistry*
  • Receptors, Opioid, mu / deficiency
  • Receptors, Opioid, mu / physiology
  • Receptors, Opioid, mu / ultrastructure*
  • Signal Transduction / physiology
  • Staining and Labeling / methods


  • GTP-Binding Protein Regulators
  • Gold Colloid
  • Receptors, Cell Surface
  • Receptors, Opioid, mu
  • GTP-Binding Proteins