Macrophage colony-stimulating factor (M-CSF) is a glycoprotein encoded by the CSF1 gene in humans that promotes the differentiation, proliferation, and function of mononuclear phagocytes, including macrophages, osteoclasts, and dendritic cells.1,2 Alternative splicing of CSF1 pre-mRNA produces one full-length long isoform (M-CSF-β), an intermediate-length isoform (M-CSF-γ), and a short-length isoform (M-CSF-α) that share sequence homology in the 150-amino acid receptor binding region that is required for the biological activity of M-CSF.3,4 M-CSF exists as a disulfide-linked homodimer where each monomer contains four α-helices, an antiparallel β-sheet, and numerous glycosylation sites.1 M-CSF is constitutively produced by many cell types, including stromal cells, osteoclasts, fibroblasts, and macrophages, and is localized to the cell surface where it can be proteolytically cleaved to yield a secreted form.5,6 Binding of M-CSF to the M-CSF receptor, which is expressed by monocytes, macrophages, osteoclasts, and dendritic cells, promotes cell differentiation, proliferation, and survival of mononuclear phagocytes and regulates bone resorption by osteoclasts.5,7 Mice homozygous for Csf1op, an inactivating mutation, exhibit defects in fertility and neural development and develop osteopetrosis, a condition characterized by increased bone density.8 Neutralization of M-CSF with a monoclonal antibody decreases joint swelling and distortion in a mouse model of collagen-induced arthritis.9 Serum M-CSF levels are increased in patients with colorectal, pancreatic, prostate, or head and neck cancer.5 M-CSF has been used to generate bone marrow-derived macrophages with an anti-inflammatory phenotype in vitro.2 Cayman's M-CSF-γ (human, recombinant) protein can be used for cell-based assay applications. This protein consist of 158 amino acids, has a calculated molecular weight of 18.4 kDa, and a predicted N-terminus of Glu37 after signal peptide cleavage. By SDS-PAGE, under reducing conditions, the molecular mass of the protein is approximately 23 kDa due to apparent post-translational modifications.WARNING This product is not for human or veterinary use.
