FEATURES

FAMILY

DESCRIPTION

Also known as DPP4_PIG, DPP4, CD26. Cell surface glycoprotein receptor involved in the costimulatory signal essential for T-cell receptor (TCR)-mediated T-cell activation. Acts as a positive regulator of T-cell coactivation, by binding at least ADA, CAV1, IGF2R, and PTPRC (PubMed:14719797). Its binding to CAV1 and CARD11 induces T-cell proliferation and NF-kappa-B activation in a T-cell receptor/CD3-dependent manner. Its interaction with ADA also regulates lymphocyte-epithelial cell adhesion. In association with FAP is involved in the pericellular proteolysis of the extracellular matrix (ECM), the migration and invasion of endothelial cells into the ECM. May be involved in the promotion of lymphatic endothelial cells adhesion, migration and tube formation. When overexpressed, enhanced cell proliferation, a process inhibited by GPC3. Acts also as a serine exopeptidase with a dipeptidyl peptidase activity that regulates various physiological processes by cleaving peptides in the circulation, including many chemokines, mitogenic growth factors, neuropeptides and peptide hormones such as brain natriuretic peptide 32. Removes N-terminal dipeptides sequentially from polypeptides having unsubstituted N-termini provided that the penultimate residue is proline (By similarity). Monomer. Homodimer (PubMed:12690074). Heterodimer with Seprase (FAP) (By similarity). Requires homodimerization for optimal dipeptidyl peptidase activity and T-cell costimulation (By similarity). Found in a membrane raft complex, at least composed of BCL10, CARD11, DPP4 and IKBKB (By similarity). Associates with collagen (By similarity). Interacts with PTPRC; the interaction is enhanced in an interleukin-12-dependent manner in activated lymphocytes (By similarity). Interacts (via extracellular domain) with ADA; does not inhibit its dipeptidyl peptidase activity (By similarity). Interacts with CAV1 (via the N-terminus); the interaction is direct (By similarity). Interacts (via cytoplasmic tail) with CARD11 (via PDZ domain); its homodimerization is necessary for interaction with CARD11 (By similarity). Interacts with IGF2R; the interaction is direct (By similarity). Interacts with GPC3 (By similarity).

EXTERNAL LINKS

DPP4

Dipeptidyl peptidase 4

DPP4

Molecular Synopsis