Low Affinity Interaction of Human or Rat T Cell Adhesion Molecule CD2 with Its Ligand Aligns Adhering Membranes to Achieve High Physiological Affinity

The mechanism by which low affinity adhesion molecules function to produce stable cell-cell adhesion is unknown. In solution, the interaction of human CD2 with its ligand CD58 is of low affinity (500 mm−1) and the interaction of rat CD2 with its ligand CD48 is of still lower affinity (40 mm−1). At t...

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Bibliographic Details
Published in:The Journal of biological chemistry 1997-12, Vol.272 (49), p.30889-30898
Main Authors: Dustin, Michael L., Golan, David E., Zhu, De-Min, Miller, James M., Meier, Werner, Davies, Elizabeth A., van der Merwe, P. Anton
Format: Article
Language:English
Subjects:
Animals
Antigens, CD - metabolism
CD2 Antigens - metabolism
CD48 Antigen
CD58 Antigens - metabolism
Cell Adhesion - physiology
Cell Membrane - metabolism
Fluorescein-5-isothiocyanate - metabolism
Humans
Jurkat Cells
Kinetics
Ligands
Lipid Bilayers - metabolism
Membranes, Artificial
Rats
Surface Properties
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Summary:The mechanism by which low affinity adhesion molecules function to produce stable cell-cell adhesion is unknown. In solution, the interaction of human CD2 with its ligand CD58 is of low affinity (500 mm−1) and the interaction of rat CD2 with its ligand CD48 is of still lower affinity (40 mm−1). At the molecular level, however, the two systems are likely to be topologically identical. Fluorescently labeled glycosylphosphatidylinositol-anchored CD48 and CD58 were prepared and incorporated into supported phospholipid bilayers, in which the ligands were capable of free lateral diffusion. Quantitative fluorescence imaging was used to study the binding of cell surface human and rat CD2 molecules to the fluorescent ligands in contact areas between Jurkat cells and the bilayers. These studies provide two major conclusions. First, CD2/ligand interactions cooperate to align membranes with nanometer precision leading to a physiologically effective two-dimensional affinity. This process does not require the intact cytoplasmic tail of CD2. Second, the degree of membrane alignment that can be achieved by topologically similar receptors deteriorates with decreasing affinity. This suggests an affinity limit for the ability of this mode of cooperativity to achieve stable cell-cell adhesion at approximately 10 mm−1.
ISSN:0021-9258
1083-351X
DOI:10.1074/jbc.272.49.30889