Immune Netw.  2005 Sep;5(3):144-149. 10.4110/in.2005.5.3.144.

Effect of Inositol-phosphatase on Fc Receptor-mediated Phagocytosis of Macrophages

• Kim JH

• KMID: 2150609
• DOI: http://doi.org/10.4110/in.2005.5.3.144

Abstract

BACKGROUND
Fc receptor-mediated phagocytosis is a complex process involving the activation of kinases and phosphatases. FcgammaRIIB has been known to transduces inhibitory signals through an immunoreceptor tyrosine-based inhibitory motif (ITIM) in cytoplasmic domains. In this study, we examined the involvement of inositol-phosphatase in the Fc receptor-mediated phagocytosis. METHODS: J774 cells were infected using vaccinia viral vector containing SH2 domain-containing inositol-phosphatase (SHIP) cDNA and stimulated with the sensitized sheep red blood cells. RESULTS: Stimulation of J774 cells induced the tyrosine phosphorylation of SHIP which was maximal at 5 minutes. Phosphatidylinositol-3 (PI-3) kinase inhibitor (wortmannin) inhibits J774 cell phagocytosis of sensitized sheep red blood cells in a dose-dependent manner. Heterologious expression of SHIP in J774 cells inhibits phagocytosis of sensitized sheep red blood cells in a dose-dependency manner, but catalytically dead mutants of SHIP has no effect on phagocytosis. CONCLUSION: These results strongly suggest that the active signals mediated by PI-3 kinase are opposed by inhibitory signals through SHIP in the regulation of Fc receptor-mediated phagocytosis.

Keyword

Fc receptor; macrophage; SH2 domain-containing inositol-phosphatase (SHIP); phagocytosis

MeSH Terms

Cytophagocytosis
Cytoplasm
DNA, Complementary
Erythrocytes
Macrophages*
Phagocytosis*
Phosphatidylinositol 3-Kinases
Phosphoric Monoester Hydrolases
Phosphorylation
Phosphotransferases
Receptors, Fc
Sheep
Ships
Tyrosine
Vaccinia
DNA, Complementary
Phosphatidylinositol 3-Kinases
Phosphoric Monoester Hydrolases
Phosphotransferases
Receptors, Fc
Tyrosine