Granulocyte macrophage colony-stimulating factor receptor

The granulocyte macrophage colony-stimulating factor receptor also known as CD116 (Cluster of Differentiation 116), is a receptor for granulocyte macrophage colony-stimulating factor, which stimulates the production of white blood cells. The receptor is normally located on myeloblast, mature neutrophil, but not on any erythroid or megakaryocytic lineage cells.

It is associated with Surfactant metabolism dysfunction type 4.

Structure

The granulocyte macrophage colony-stimulating factor receptor is a heterodimer composed of at least two different subunits; an α chain, and a β chain which is also present in the receptors for IL-3 and IL-5. The α subunit contains a binding site for granulocyte macrophage colony-stimulating factor. The β chain is involved in signal transduction. Association of the α and β subunits results in receptor activation.

Signal transduction

Upon dimerisation of the α and β subunits the β subunit becomes phosphorylated on tyrosine residues by members of the Janus kinase (JAK) family. This leads to association with a Shc adaptor protein. Then Shc interacts with GRB2/SoS complex which results in activation of more downstream molecules in the pathway.

Granulocyte macrophage colony-stimulating factor

Granulocyte-macrophage colony-stimulating factor (GM-CSF), also known as colony stimulating factor 2 (CSF2), is a monomeric glycoprotein secreted by macrophages, T cells, mast cells, NK cells, endothelial cells and fibroblasts that functions as a cytokine. The pharmaceutical analogs of naturally occurring GM-CSF are called sargramostim and molgramostim.

Function

GM-CSF is a monomeric glycoprotein that functions as a cytokine - it is a white blood cell growth factor. GM-CSF stimulates stem cells to produce granulocytes (neutrophils, eosinophils, and basophils) and monocytes. Monocytes exit the circulation and migrate into tissue, whereupon they mature into macrophages and dendritic cells. Thus, it is part of the immune/inflammatory cascade, by which activation of a small number of macrophages can rapidly lead to an increase in their numbers, a process crucial for fighting infection.

GM-CSF also has some effects on mature cells of the immune system. These include, for example, inhibiting neutrophil migration and causing an alteration of the receptors expressed on the cells surface.