Involvement of pp125FAK and p60SRC in the signaling through FcγRII-FcγRIII in murine macrophages

Cross-linking the FcyRs can activate a wide variety of biological responses in macrophages. Receptor stimulation induces activation of protein tyrosine kinase cascades that result in phagocytosis. a process known to involve cytoskeletal rearrangements. Therefore, an involvement of non-receptor tyrosine kinases such as pp125(FAK), in FcyR signaling is likely. Using the murine macrophage cell line J774. we demonstrate that Fcy7RII-RIII cross-linking induces a time- and dose-dependent increase in tyrosine phosphorylation of the focal adhesion kinase pp125(FAK) that correlates with an increase in its catalytic activity. Interestingly enough. pp125(FAK) activation results in its association both to the FcyRII-III and to p60(Src). The results presented here define a novel-signaling pathway likely to be important in low affinity FcyRII-III mediated phagocytosis. (C) 2001 Elsevier Science B.V. All rights reserved.