CSF1R (Colony stimulating factor 1 receptor,M-CSFR,CD115) is a receptor for a cytokine called colony stimulating factor 1. It controls the production, differentiation, and function of macrophages. This receptor mediates most, if not all, of the biological effects of this cytokine. Ligand binding activates CSF1R through a process of oligomerization and trans-phosphorylation. The encoded protein is a tyrosine kinase transmembrane receptor and member of the CSF1/PDGF receptor family of tyrosine-protein kinases.