Cytokine that stimulates the growth and differentiation of hematopoietic precursor cells from various lineages, including granulocytes, macrophages, eosinophils and erythrocytes. Monomer. The signaling GM-CSF receptor complex is a dodecamer of two head-to-head hexamers of two alpha, two beta, and two ligand subunits (By similarity). Belongs to the GM-CSF family.