Discription：Macrophage Colony Stimulating Factor （M-CSF） , also named CSF-1, is a hematopoietic growth factor that is involved in the proliferation, differentiation, and survival of monocytes, macrophages, and bone marrow progenitor cells. It is produced by osteoblasts （as a result of endocrine stimulation by parathyroid hormone） exerts paracrine effects on osteoclasts and can interact with CSF1R. M-CSF is a four α-helical bundle cytokine and its active form is found extracellularly as a disulfide-linked homodimer. Four transcript variants encoding three different isoforms have been reported for M-CSF gene. Although forms may vary, all of them contain the N-terminal 150 a.a. portion that is necessary and sufficient for interaction with the receptor. The first 223 a.a. of mature human M-CSF shares 88％, 86％, 81％ and 74％ sequence identity with corresponding regions of dog, cow, mouse and rat M-CSF, respectively. Human M-CSF is active in the mouse, but mouse M-CSF is reported to be species-specific. Recombinant human M-CSF is a 36.8kDa homodimeric protein consisting of two 159 amino acid polypeptide subunits.
