The Journal of Immunology, Vol 151, Issue 7 3817-3828, Copyright © 1993 by American Association of Immunologists

ARTICLES

Co-clustering of beta 1 integrins, cytoskeletal proteins, and tyrosine- phosphorylated substrates during integrin-mediated leukocyte aggregation

P Sanchez-Mateos, MR Campanero, MA Balboa and F Sanchez-Madrid
Seccion de Inmunologia, Hospital de la Princesa, Universidad Autonoma de Madrid, Spain.

The involvement of the VLA-4 integrin in an alternative leukocyte homotypic adhesion mechanism that is LFA-1/ICAM-1 independent, has been previously reported. We describe here the localization of beta 1 and alpha 4 integrin subunits at sites of cell-cell contact, on both beta 1- and alpha 4-induced aggregates of B lymphoblastoid Ramos cells. Moreover, the distribution of different VLA-alpha subunits was also examined on beta 1-induced cell aggregates of alpha 2- and alpha 4- transfected K-562 cells. Both alpha 2 and alpha 4 integrin subunits were mainly localized at sites of intercellular boundaries, suggesting a possible role for these integrins in leukocyte intercellular adhesion. The fibronectin receptor alpha 5 subunit was either diffuse throughout the plasma membrane, or displayed some accumulation at sites of cell-cell contact. Even though homotypic aggregation of U-937 cells was induced with the anti-alpha 5 P1D6 mAb, the alpha 5 subunit showed only partial redistribution to regions of cell-cell contact, compared with the complete redistribution of the alpha 4 subunit in the alpha 4- induced aggregates. The reorganization of the actin-cytoskeleton was observed at sites of intercellular boundaries in both the anti-beta 1- and anti-alpha 4-induced cell aggregates. Hence, F-actin and the cytoskeletal protein talin co-localized with beta 1 and alpha 4 integrin clusters at sites of cell-cell contact. Signal transduction during VLA-mediated homotypic cell adhesion has also been investigated. We found co-localization of beta 1 and alpha 4 subunits with tyrosine- phosphorylated proteins at cell-cell contact regions during cell aggregation. These data indicate that VLA integrin-mediated leukocyte aggregation results in clustering of beta 1-integrins at sites of cell- cell contact, together with co-localization of cytoskeletal proteins. These results also suggest that protein tyrosine phosphorylation is an important signal transduction mechanism when VLA integrins participate in intercellular contacts.

This article has been cited by other articles:

				E. Pluskota, D. A. Soloviev, D. Szpak, C. Weber, and E. F. Plow Neutrophil Apoptosis: Selective Regulation by Different Ligands of Integrin {alpha}M{beta}2 J. Immunol., September 1, 2008; 181(5): 3609 - 3619. [Abstract] [Full Text] [PDF]

				G. J. Zwartz, A. Chigaev, D. C. Dwyer, T. D. Foutz, B. S. Edwards, and L. A. Sklar Real-time Analysis of Very Late Antigen-4 Affinity Modulation by Shear J. Biol. Chem., September 10, 2004; 279(37): 38277 - 38286. [Abstract] [Full Text] [PDF]

				H.-B. Guo, I. Lee, M. Kamar, and M. Pierce N-Acetylglucosaminyltransferase V Expression Levels Regulate Cadherin-associated Homotypic Cell-Cell Adhesion and Intracellular Signaling Pathways J. Biol. Chem., December 26, 2003; 278(52): 52412 - 52424. [Abstract] [Full Text] [PDF]

				A. Chigaev, G. Zwartz, S. W. Graves, D. C. Dwyer, H. Tsuji, T. D. Foutz, B. S. Edwards, E. R. Prossnitz, R. S. Larson, and L. A. Sklar {alpha}4{beta}1 Integrin Affinity Changes Govern Cell Adhesion J. Biol. Chem., October 3, 2003; 278(40): 38174 - 38182. [Abstract] [Full Text] [PDF]

				N. Longo, M. Yanez-Mo, M. Mittelbrunn, G. de la Rosa, M.-L. Munoz, F. Sanchez-Madrid, and P. Sanchez-Mateos Regulatory role of tetraspanin CD9 in tumor-endothelial cell interaction during transendothelial invasion of melanoma cells Blood, December 15, 2001; 98(13): 3717 - 3726. [Abstract] [Full Text] [PDF]

				J. Xiao, Y. Messinger, J. Jin, D. E. Myers, J. B. Bolen, and F. M. Uckun Signal Transduction through the beta1 Integrin Family Surface Adhesion Molecules VLA-4 and VLA-5 of Human B-cell Precursors Activates CD19 Receptor-associated Protein-tyrosine Kinases J. Biol. Chem., March 29, 1996; 271(13): 7659 - 7664. [Abstract] [Full Text] [PDF]

				A. Chigaev, A. M. Blenc, J. V. Braaten, N. Kumaraswamy, C. L. Kepley, R. P. Andrews, J. M. Oliver, B. S. Edwards, E. R. Prossnitz, R. S. Larson, et al. Real Time Analysis of the Affinity Regulation of alpha 4-Integrin. THE PHYSIOLOGICALLY ACTIVATED RECEPTOR IS INTERMEDIATE IN AFFINITY BETWEEN RESTING AND Mn2+ OR ANTIBODY ACTIVATION J. Biol. Chem., December 21, 2001; 276(52): 48670 - 48678. [Abstract] [Full Text] [PDF]