Description: Macrophage colony-stimulating factor (M-CSF or CSF-1) is a survival factor essential for the proliferation and development of monocytes, macrophages, and osteoclast progenitor cells. M-CSF also induces VEGF (vascular endothelial growth factor) secretion by macrophages, thereby mediating mobilization of endothelial progenitor cells and neovascularization.
M-CSF is present as several bioactive isoforms that differ in potency and stability. The full-length protein is synthesized as a membrane-spanning protein that can be expressed on the cell surface or further cleaved and modified in the secretory vesicle. The secreted protein is a disulfide-bonded homodimer which is processed into one of two isoforms, a glycoprotein or a proteoglycan that has been modified by the addition of chondroitin sulfate to each subunit. Binding of M-CSF to its receptor, c-Fms (CSF-1R or CD115) induces dimerization of the receptor followed by internalization and degradation of the complex.