M-CSF R

Macrophage colony-stimulating factor receptor (M-CSFR, CSF1R, CD115) is a class III receptor tyrosine kinase expressed on monocytes, macrophages and their progenitors, as well as Langerhans cell precursors. Binding of its ligands M-CSF and IL-34 induces receptor homodimerization and trans-autophosphorylation of the intracellular kinase domain, activating SRC family kinases, PI3K-AKT, MAPK and STAT3 pathways that deliver survival, proliferation and differentiation signals to the mononuclear phagocyte lineage. M-CSFR signaling specifies macrophage fate from common myeloid progenitors, supports osteoclast generation and bone resorption together with RANKL, and sustains tissue-resident macrophages and microglia. Loss-of-function CSF1R mutations cause hereditary diffuse leukoencephalopathy with axonal spheroids, while receptor overactivation contributes to chronic inflammation, atherosclerosis and tumor-associated macrophage accumulation; CSF1R inhibitors are clinically approved for tenosynovial giant cell tumors.