Recombinant Human M-CSF/CSF1 (His, Flag)

Macrophage colony-stimulating factor (M-CSF), also known as CSF-1, is a tetra α-helical bundle cytokine that is a major regulator of macrophage survival, proliferation, and differentiation. M-CSF is also essential for the survival and proliferation of osteoclast progenitor cells. M-CSF also initiates and enhances macrophage killing of tumor cells and microorganisms, regulates the release of cytokines and other inflammatory modulators by macrophages, and stimulates pinocytosis. M-CSF is increased during pregnancy to support the implantation and growth of the decidua and placenta. Sources of M-CSF include fibroblasts, activated macrophages, endometrial secretory epithelium, bone marrow stromal cells, and activated endothelial cells. The M-CSF receptor (c-fms) conducts its pleiotropy and mediates its endocytosis. M-CSF mRNA of various sizes appears. The full-length human M-CSF transcript encodes a type I transmembrane (TM) protein with 522 amino acids (aa), 464 aa in the extracellular domain, 21 aa in the TM domain, and 37 aa in the cytoplasmic tail, forming a 140 kDa covalent dimer. Differential processing yields two protein cleavage secretory dimers. One is an N- and O-glycosylated 86 kDa dimer, while the other is a glycosylated and chondroitin sulfate proteoglycan (PG)-modified 200 kDa subunit. Although PG-modified M-CSF can be circulated, it may be fixed by attachment to type V collagen. The shorter transcript encodes M-CSF lacking cleavage and PG sites and yields an n-glycosylated 68 kDaTM dimer and a slow-producing 44 kDa secreted dimer. Although the forms may vary in activity and half-life, they all contain an N-terminal 150 aa moiety.