Colony-stimulating factor-1 receptor (c-fms)

Abstract

The macrophage colony‐stimulating factor, CSF‐1 (M‐CSF), is a homodimeric glycoprotein required for the lineage‐specific growth of cells of the mononuclear phagocyte series. Apart from its role in stimulating the proliferation of bone marrow‐derived precursors of monocytes and macrophages, CSF‐1 acts as a survival factor and primes mature macrophages to carry out differentiated functions. Each of the actions of CSF‐1 are mediated through its binding to a single class of high‐affinity receptors expressed on monocytes, macrophages, and their committed progenitors. The CSF‐1 receptor (CSF‐1R) is encoded by the c‐fms proto‐oncogene, and is one of a family of growth factor receptors that exhibits an intrinsic tyrosine‐specific protein kinase activity. Transduction of c‐fms sequences as a viral oncogene (v‐fms) in the McDonough (SM) and HZ‐5 strains of feline sarcoma virus has resulted in alterations in receptor coding sequences that affect its activity as a tyrosine kinase and provide persistent signals for cell growth in the absence of its ligand. The genetic alterations in the c‐fms gene that unmask its latent transforming potential abrogate its lineage‐specific activity and enable v‐fms to transform a variety of cells that do not normally express CSF‐1 receptors.