CD26/DPP4 [MD43R]

CD26 (DPP4) is a type II transmembrane glycoprotein expressed specifically in lymphatic vessels but not in blood vessels in the skin, small intestine, esophagus, ovary, breast and prostate glands. Expressed in the poorly differentiated crypt cells of the small intestine as well as in the mature villous cells. Not detected in lymphatic vessels in the lung, kidney, uterus, liver and stomach (at protein level). Expressed at very low levels in the colon. The protein has a short cytoplasmic domain, transmembrane domain, a flexible stalk fragment and extracellular fragment. Both the catalytic peptide hydrolase domain and the beta-propeller ligand binding domain are located in the extracellular fragment. DPP4 is a multifunctional protein that exists in both a membrane bound form as well as an extracellular soluble form. As a peptidase, it removes N-terminal dipeptides sequentially from proteins with a proline or alanine as the penultimate P1 amino acid. DPP4 has been shown to cleave a wide range of substrates including GLP-1, BNP, substance P, etc. It is also involved in the regulation of related biological functions. In addition to it peptidase activity, DPP4 interacts with multiple important cell surface ligands, such as adenosine deaminase, fibronectin, and IGF2 receptor to influence processes like T cell activation, cell migration and proliferation. Several DPP4 inhibitors have been developed and their effects have been tested in the field of diabetes, cardiovascular disease and tumor immunity.