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Chapter 9,761

Activation of b1 integrins induces cell-cell adhesion

Whittard, J.D.; Akiyama, S.K.

Experimental Cell Research 263(1): 76

2001


ISSN/ISBN: 0014-4827
Accession: 009760029

Integrins are highly regulated receptors that can function in both cell-substrate and cell-cell adhesion. We have found that the activating anti-b1 mAb, 12G10, can specifically and rapidly induce both cell-substrate and cell-cell adhesion of HT-1080 human fibrosarcoma and other cell types. Binding of mAb 12G10 induced clustering of cell-surface integrins, and the preferential localization of b1 integrins expressing the 12G10 epitope at cell-cell adhesion sites. Fab fragments of mAb 12G10 induced HT-1080 cell-cell adhesion as effectively as did intact antibodies, suggesting that integrin clustering was not due to direct antibody crosslinking. Latrunculin B, an inhibitor of F-actin polymerization, inhibited cell-cell adhesion but not the clustering of integrins. Results from a novel, two-color cell-cell adhesion assay suggested that nonactivated cells can bind to activated cells and that integrin activation-induced HT-1080 cell-cell adhesion minimally requires the interaction of activated a2b1 with nonactivated a3b1. These findings suggest that HT-1080 cell-cell adhesion induced by integrin activation require a signaling process involving integrin clustering and the subsequent organization of the cytoskeleton. Integrin activation could therefore play a key role in cell-cell adhesion.

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