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CD117 is a cytokine receptor expressed on the surface of hematopoietic stem cells as well as other cell types.

Contents

Synonyms

Cell Surface Marker

Ligand

Function

Mobilization

Role in cancer

See also

References

External links

Synonyms

c-Kit, KIT

Cell Surface Marker

Cluster of differentiation (CD) molecules are markers on the cell surface, as recognized by specific sets of antibodies, used to identify the cell type, stage of differentiation and activity of a cell. CD117 is an important cell surface marker used to identify certain types of hematopoietic (blood) progenitors in the bone marrow. Specifically hematopoietic stem cells (HSC), multipotent progenitors (MPP), and common myeloid progenitors (CMP) express high levels of CD117. Common lymphoid progenitors (CLP) expresses low surface levels of CD117.
CD117 also identifies the earliest thymocyte progenitors in the thymus. Specifically early T lineage progenitors (ETP/DN1) and DN2 thymocytes express high levels of c-Kit.
Additionally mast cells, melanocytes in the skin, and interstitial cells of Cajal in the digestive tract express CD117.

Ligand

CD117 is the receptor for the cytokine stem cell factor (SCF), also known as "steel factor" or "c-kit ligand". SCF exists in two forms, cell surface bound SCF and soluble (or free) SCF.

Function

CD117 is a receptor tyrosine kinase type III. When this receptor binds to SCF it forms a dimer which activates signaling through second messengers. Signaling through CD117 plays a role in cell survival, proliferation, and differentiation.

Mobilization

Hematopoietic progenitor cells are normally present in the blood at low levels. Mobilization is the process by which progenitors are made to migrate from the bone marrow into the bloodstream, thus increasing their numbers in the blood. Mobilization is used clinically as a source of hematopoietic stem cells for hematopoietic stem cell transplantation (HSCT). Signaling through CD117 has been implicated in mobilization. Currently, G-CSF is the main drug used for mobilization. G-CSF indirectly activates CD117. Direct CD117 agonists are currently being developed as mobilization agents.

Role in cancer

CD117 is a proto-oncogene, meaning that mutations of this protein can lead to cancer^[1]. Mutations of CD117 have been implicated in leukemia which is a cancer of hematopoietic progenitors. Also CD117 mutations in the interstitial cells of Cajal can lead to gastrointestinal stromal tumors (GISTs), and explain the efficacy of imatinib, a CD117 inhibitor, in the management of these rare malignancies.

See also

★ Cluster of differentiation

★ cytokine receptor

★ receptor tyrosine kinase

★ tyrosine kinase

★ oncogene

★ hematopoiesis

References

1. http://AtlasGeneticsOncology.org/Genes/KITID127.html

External links

★

★ c-Kit-A hematopoietic cell essential receptor tyrosine kinase, Edling CE, Hallberg B, , , , 2007