The granulocyte colony-stimulating factor receptor (G-CSF-R) also known as CD114 (Cluster of Differentiation 114) is a protein that in humans is encoded by the CSF3R gene. G-CSF-R is a cell-surface receptor for the granulocyte colony-stimulating factor (G-CSF). The G-CSF receptors belong to a family of cytokine receptors known as the hematopoietin receptor family. The granulocyte colony-stimulating factor receptor is present on precursor cells in the bone marrow, and, in response to stimulation by G-CSF, initiates cell proliferation and differentiation into mature neutrophilic granulocytes and macrophages. The G-CSF-R is a transmembrane receptor that consists of an extracellular ligand-binding portion, a transmembrane domain, and the cytoplasmic portion that is responsible for signal transduction. GCSF-R ligand-binding is associated with dimerization of the receptor and signal transduction through proteins including Jak, Lyn, STAT, and Erk1/2.