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The SH2-Containing Inositol-5'-Phosphatase Enhances LFA-1-Mediated Cell Adhesion and Defines Two Signaling Pathways for LFA-1 Activation
The inside-out signaling involved in the activation of LFA-1-mediated cell adhesion is still poorly understood. Here we examined the role of the SH2-containing inositol phosphatase (SHIP), a major negative regulator of intracellular signaling, in this process. Wild-type SHIP and a phosphatase-defici...
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Published in: | The Journal of immunology (1950) 1999-05, Vol.162 (10), p.5792-5799 |
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Main Authors: | , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | The inside-out signaling involved in the activation of LFA-1-mediated cell adhesion is still poorly understood. Here we examined the role of the SH2-containing inositol phosphatase (SHIP), a major negative regulator of intracellular signaling, in this process. Wild-type SHIP and a phosphatase-deficient mutant SHIP were overexpressed in the murine myeloid cell line, DA-ER, and the effects on LFA-1-mediated cell adhesion to ICAM-1 (CD54) were tested. Overexpression of wild-type SHIP significantly enhanced cell adhesion to immobilized ICAM-1, and PMA, IL-3, or erythropoietin further augmented this adhesion. In contrast, phosphatase dead SHIP had no enhancing effects. Furthermore, PMA-induced activation of LFA-1 on DA-ER cells overexpressing wild-type SHIP was dependent on protein kinase C but independent of mitogen-activated protein kinase activation, whereas cytokine-induced activation was independent of protein kinase C and mitogen-activated protein kinase activation but required phosphatidylinositol-3 kinase activation. These results suggest that SHIP may regulate two distinct inside-out signaling pathways and that the phosphatase activity of SHIP is essential for both of them. |
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ISSN: | 0022-1767 1550-6606 |
DOI: | 10.4049/jimmunol.162.10.5792 |