Confined Lateral Diffusion of Membrane Receptors as Studied by Single Particle Tracking (Nanovid Microscopy). Effects of Calcium-Induced Differentiation in Cultured Epithelial Cells

Biophys J. 1993 Nov;65(5):2021-40. doi: 10.1016/S0006-3495(93)81253-0.

Abstract

The movements of E-cadherin, epidermal growth factor receptor, and transferrin receptor in the plasma membrane of a cultured mouse keratinocyte cell line were studied using both single particle tracking (SPT; nanovid microscopy) and fluorescence photobleaching recovery (FPR). In the SPT technique, the receptor molecules are labeled with 40 nm-phi colloidal gold particles, and their movements are followed by video-enhanced differential interference contrast microscopy at a temporal resolution of 33 ms and at a nanometer-level spatial precision. The trajectories of the receptor molecules obtained by SPT were analyzed by developing a method that is based on the plot of the mean-square displacement against time. Four characteristic types of motion were observed: (a) stationary mode, in which the microscopic diffusion coefficient is less than 4.6 x 10(-12) cm2/s; (b) simple Brownian diffusion mode; (c) directed diffusion mode, in which unidirectional movements are superimposed on random motion; and (d) confined diffusion mode, in which particles undergoing Brownian diffusion (microscopic diffusion coefficient between 4.6 x 10(-12) and 1 x 10(-9) cm2/s) are confined within a limited area, probably by the membrane-associated cytoskeleton network. Comparison of these data obtained by SPT with those obtained by FPR suggests that the plasma membrane is compartmentalized into many small domains 300-600 nm in diameter (0.04-0.24 microns2 in area), in which receptor molecules are confined in the time scale of 3-30 s, and that the long-range diffusion observed by FPR can occur by successive movements of the receptors to adjacent compartments. Calcium-induced differentiation decreases the sum of the percentages of molecules in the directed diffusion and the stationary modes outside of the cell-cell contact regions on the cell surface (which is proposed to be the percentage of E-cadherin bound to the cytoskeleton/membrane-skeleton), from approximately 60% to 8% (low- and high-calcium mediums, respectively).

MeSH terms

  • Animals
  • Biophysical Phenomena
  • Biophysics
  • Cadherins / metabolism
  • Calcium / pharmacology
  • Cell Differentiation / drug effects
  • Cell Line
  • Cell Membrane / drug effects
  • Cell Membrane / metabolism
  • Diffusion
  • ErbB Receptors / metabolism
  • Fluorescence
  • Gold Colloid
  • Keratinocytes / cytology
  • Keratinocytes / drug effects
  • Keratinocytes / metabolism*
  • Membrane Proteins / metabolism
  • Mice
  • Microscopy, Interference
  • Models, Biological
  • Photochemistry
  • Receptors, Cell Surface / metabolism*
  • Receptors, Transferrin / metabolism

Substances

  • Cadherins
  • Gold Colloid
  • Membrane Proteins
  • Receptors, Cell Surface
  • Receptors, Transferrin
  • ErbB Receptors
  • Calcium