G-CSF R-Fc Chimera

G-CSF R, also known as granulocyte colony-stimulating factor receptor and CD114 antigen, is a member of the cytokine receptor superfamily.  Members of this family, which also includes the receptors for IL-2 to IL-7, GM-CSF, EPO, TPO and GH, are characterised by the presence of four conserved cysteine residues in their extracellular domains. The G CSF R extracellular domain has a composite structure containing an Ig-like domain, a cytokine receptor homologous region and fibronectin type III domains.

The human G-CSF R mediates the biological activity of G-CSF which is unique in its ability to not only stimulate the proliferation but also potently induces the terminal maturation of myeloid progenitor cells to neutrophilic granulocytes.

Symansis G-CSF R is produced as an ECD-Fc fusion protein with the aim of enhancing its activity. ECD-Fc fusion proteins have an advantage over soluble receptors because many receptors are only functional in dimeric form. Fusion to the Fc domain of IgG1 induces dimerization due to the ability of the Fc domain to form disulfide bonds. The resulting dimeric receptor ECD-Fc mimics the activated form of the receptor and possess enhanced affinity for its cognate ligand relative to its monomeric form.

For a comprehensive review please see Avalos BR (1996) Blood 88(3): 761-777