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A critical role for syk in signal transduction and phagocytosis mediated by Fc� receptors on macrophages (1997)
| Content Provider | CiteSeerX |
|---|---|
| Author | Turner, Martin Crowley, T. Lowell, Clifford Tybulewicz, Victor L. J. Defranco, Anthony L. Fitzer-Attas, Cheryl J. Meng, Fanying Costello, Patrick S. |
| Abstract | Receptors on macrophages for the Fc region of IgG (Fc�R) mediate a number of responses important for host immunity. Signaling events necessary for these responses are likely initiated by the activation of Src-family and Syk-family tyrosine kinases after Fc�R cross-linking. Macrophages derived from Syk-deficient (Syk � ) mice were defective in phagocytosis of particles bound by Fc�Rs, as well as in many Fc�R-induced signaling events, including tyrosine phosphorylation of a number of cellular substrates and activation of MAP kinases. In contrast, Syk � macrophages exhibited normal responses to another potent macrophage stimulus, lipopolysaccharide. Phagocytosis of latex beads and Escherichia coli bacteria was also not affected. Syk � macrophages exhibited formation of polymerized actin structures opposing particles bound to the cells by Fc�Rs (actin cups), but failed to proceed to internalization. Interestingly, inhibitors of phosphatidylinositol 3-kinase also blocked Fc�R-mediated phagocytosis at this stage. Thus, PI 3-kinase may participate in a Syk-dependent signaling pathway critical for Fc�R-mediated phagocytosis. Macrophages derived from mice deficient for the three members of the Src-family of kinases expressed in these cells, Hck, Fgr, and Lyn, exhibited poor Syk activation upon Fc�R engagement, accompanied by a delay in Fc�R-mediated phagocytosis. |
| File Format | |
| Publisher Date | 1997-01-01 |
| Publisher Department | Department Of Microbiology |
| Access Restriction | Open |
| Subject Keyword | Map Kinase Signal Transduction Actin Cup Critical Role Syk Macrophage Many Fc R-induced Fc Region Fc Engagement Syk-family Tyrosine Kinase Fc R Pi 3-kinase Fc R-mediated Phagocytosis Potent Macrophage Stimulus Polymerized Actin Structure Mouse Deficient Latex Bead Host Immunity Fc Receptor Normal Response Tyrosine Phosphorylation Phosphatidylinositol 3-kinase Fc Cross-linking Cellular Substrate Poor Syk Activation |
| Content Type | Text |
