Proto-oncogene protein c-kit, also known as c-KIT or CD117, is a cell surface receptor protein that is encoded by the KIT proto-oncogene. It belongs to the receptor tyrosine kinase family and is commonly found on the surface of certain cells, including hematopoietic stem cells, melanocytes, and interstitial cells of Cajal.
The c-KIT protein plays a crucial role in cell signaling and regulation of cell growth and differentiation. It acts as a receptor for a growth factor called stem cell factor (SCF), also known as KIT ligand. When SCF binds to the c-KIT receptor, it triggers a signaling cascade that activates various downstream pathways, including the RAS/RAF/MEK/ERK and PI3K/AKT pathways, promoting cell proliferation, survival, and differentiation.
Mutations or overexpression of the c-KIT gene can lead to aberrant activation of the c-KIT protein, resulting in uncontrolled cell growth and division. Such genetic alterations are commonly associated with certain types of cancers, including gastrointestinal stromal tumors (GISTs), mastocytosis, acute myeloid leukemia (AML), and melanoma.
The expression of c-KIT protein is commonly assessed in diagnostic testing and targeted therapy for certain malignancies, as it serves as a potential therapeutic target. Drugs specifically designed to inhibit the activity of c-KIT, such as imatinib mesylate (Gleevec), have shown promising results in treating patients with c-KIT-mutated cancers, inhibiting the abnormal signaling and blocking the excessive cell growth associated with these conditions.
