M-CSF R/CD115
M-CSF R, the CD115 antigen, is the receptor tyrosine kinase encoded by CSF1R and belongs to the class III RTK subfamily together with c-Kit, PDGFR and Flt3. Ligand binding by M-CSF (CSF1) or IL-34 induces dimerization and autophosphorylation, activating MAPK, PI3K and Src pathways that drive macrophage survival, proliferation and differentiation. The receptor is essential for development of the mononuclear phagocyte system and for osteoclast formation, and its expression marks monocytes, macrophages and their tissue residents. Blocking CSF1R has become a strategy for depleting tumor-associated macrophages, and several anti-CSF1R antibodies are in clinical oncology development.
