The role of the DAP12 signal in mouse myeloid differentiation

DAP12. is a recently cloned, immunoreceptor tyrosine-based activation motif -bearing transmembrane adapter molecule that is associated with the NK-acti vating receptors, Previous reports showed that the DAP12 message could be d etected not only in NK cells but also in granulocytes, monocytes, dendritic cells, and macrophages, In this study we found a significant level of DAP1 2 protein expression in macrophage-related cell lines and organs. Additiona lly, we observed increased expression of DAP12, after LPS-induced different iation of M1 cells into macrophages, To examine the role of DAP12 in the my eloid cell lineage, we established M1 FLAG-DAP12 transfectants (FDAP-M1) an d demonstrated the marked;morphological changes in FDAP-M1 cells caused by signaling through DAP12 Cell surface phenotypic analysis showed up-regulati on of macrophage markers CD11b, 2,4G2, and adhesion molecule B7-2, Addition ally, after stimulation through DAP12, phosphorylated FLAG -DAP12 could be immunoprecipitated using anti-phosphotyrosine mAbs, Collectively, these fin dings indicate that direct DAP12 signaling has an important role in macroph age differentiation.