GMCSF is a cytokine that controls the production，differentiation，and function of granulocytes and macrophages. The active form of the protein is found extracellularly as a homodimer. This gene has been localized to a cluster of related genes at chromosome region 5q31，which is known to be associated with interstitial deletions in the 5q- syndrome and acute myelogenous leukemia. Other genes in the cluster include those encoding interleukins 4，5，and 13.
GM-CSF stimulates the growth and differentiation of hematopoietic precursor cells from various lineages，including granulocytes，macrophages，eosinophils and erythrocytes.
