Cross-linking of cell surface receptors enhances cooperativity of molecular adhesion.
Cooperativity of molecular adhesion has been proposed as a mechanism for enhanced binding strength of adhesion molecules on the cell surface. Direct evidence for its mechanism, however, has been lacking until now. Atomic force microscopy (AFM) was used to measure the adhesive strength between concanavalin A (Con A) coupled to an AFM tip and Con A receptors on the surface of NIH3T3 fibroblast cells. Cross-linking of receptors with either glutaraldehyde or 3, 3'-dithio-bis(sulfosuccinimidylproprionate) (DTSSP) led to an increase in adhesion that could be attributed to enhanced cooperativity among adhesion complexes. An increase in loading rate due to greater stiffness of fixed cells also contributed to the twofold increase in binding strength. These results show that receptor cross-linking can greatly contribute to a total increase in cell adhesion by creating a shift toward cooperative binding of receptors.
Chen
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Department of Physiology and Biophysics and Neuroscience Program, University of Miami School of Medicine, Florida 33136, USA.
Moy
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D016475:3T3 Cells; D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology*; D003208:Concanavalin A / Q000378:metabolism; D003432:Cross-Linking Reagents; D005976:Glutaral / Q000494:pharmacology; D051379:Mice; D018625:Microscopy, Atomic Force; D008954:Models, Biological; D011956:Receptors, Cell Surface / Q000502:physiology*; D011952:Receptors, Concanavalin A / Q000187:drug effects / Q000502:physiology*; D013388:Succinimides / Q000494:pharmacology
D003432:Cross-Linking Reagents; D011956:Receptors, Cell Surface; D011952:Receptors, Concanavalin A; D013388:Succinimides; D003208:Concanavalin A; C035759:3,3'-dithiobis(sulfosuccinimidyl propionate); D005976:Glutaral