Restructuring of Focal Adhesion Plaques by Pi 3-Kinase
| Autor: | Glenn D. Prestwich, Anne B. Theibert, Joanne E. Murphy-Ullrich, Jeffrey A. Greenwood |
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| Rok vydání: | 2000 |
| Předmět: | |
| Zdroj: | Journal of Cell Biology. 150:627-642 |
| ISSN: | 1540-8140 0021-9525 |
| DOI: | 10.1083/jcb.150.3.627 |
| Popis: | Focal adhesions are an elaborate network of interconnecting proteins linking actin stress fibers to the extracellular matrix substrate. Modulation of the focal adhesion plaque provides a mechanism for the regulation of cellular adhesive strength. Using interference reflection microscopy, we found that activation of phosphoinositide 3-kinase (PI 3-kinase) by PDGF induces the dissipation of focal adhesions. Loss of this close apposition between the cell membrane and the extracellular matrix coincided with a redistribution of α-actinin and vinculin from the focal adhesion complex to the Triton X-100–soluble fraction. In contrast, talin and paxillin remained localized to focal adhesions, suggesting that activation of PI 3-kinase induced a restructuring of the plaque rather than complete dispersion. Furthermore, phosphatidylinositol (3,4,5)-trisphosphate (PtdIns (3,4,5)-P3), a lipid product of PI 3-kinase, was sufficient to induce restructuring of the focal adhesion plaque. We also found that PtdIns (3,4,5)-P3 binds to α-actinin in PDGF-treated cells. Further evidence demonstrated that activation of PI 3-kinase by PDGF induced a decrease in the association of α-actinin with the integrin β subunit, and that PtdIns (3,4,5)-P3 could disrupt this interaction in vitro. Modification of focal adhesion structure by PI 3-kinase and its lipid product, PtdIns (3,4,5)-P3, has important implications for the regulation of cellular adhesive strength and motility. |
| Databáze: | OpenAIRE |
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