catalytic activity:Release of an N-terminal dipeptide, Xaa-Yaa-|-Zaa-, from a polypeptide, preferentially when Yaa is Pro, provided Zaa is neither Pro nor hydroxyproline.,function:Removes N-terminal dipeptides sequentially from polypeptides having unsubstituted N-termini provided that the penultimate residue is proline. Plays a role in T-cell activation.,online information:Dipeptidyl peptidase-4 entry,PTM:The soluble form (SDPP) derives from the membrane form (MDPP) by proteolytic processing.,similarity:Belongs to the peptidase S9B family. DPPIV subfamily.,subunit:Homodimer or heterodimer with Seprase (FAP).,tissue specificity:Expressed in the poorly differentiated crypt cells of the small intestine as well as in the mature villous cells. Expressed at very low levels in the colon.,
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Function:
response to hypoxia, cell activation, regulation of immune effector process, regulation of leukocyte mediated immunity,regulation of lymphocyte mediated immunity, regulation of T cell mediated immunity, regulation of adaptive immune response, regulation of adaptive immune response based on somatic recombination of immune receptors built from immunoglobulin superfamily domains, proteolysis, regulation of cell-cell adhesion, regulation of cell adhesion,regulation of cell adhesion mediated by integrin, regulation of cell-cell adhesion mediated by integrin, T cell activation,leukocyte activation, lymphocyte activation, response to oxygen levels,
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Cellular Localization:
[Dipeptidyl peptidase 4 soluble form]: Secreted . Detected in the serum and the seminal fluid. .; Cell membrane ; Single-pass type II membrane protein. Apical cell membrane ; Single-pass type II membrane protein. Cell projection, invadopodium membrane ; Single-pass type II membrane protein. Cell projection, lamellipodium membrane ; Single-pass type II membrane protein. Cell junction . Membrane raft . Translocated to the apical membrane through the concerted action of N- and O-Glycans and its association with lipid microdomains containing cholesterol and sphingolipids (PubMed:11773049). Redistributed to membrane rafts in T-cell in an interleukin-12-dependent activation (PubMed:12676959). Its interaction with CAV1 is necessary for its translocation to membrane rafts (PubMed:17287217). Colocalized with PTPRC in membrane rafts (PubMed:12676959). Colocalized with FAP in invadopodia and lamellipodia of migratory activated endothelial cells in collagenous matrix. Colocalized with FAP on endothelial cells of capillary-like microvessels but not large vessels within invasive breast ductal carcinoma (PubMed:16651416). Colocalized with ADA at the cell junction in lymphocyte-epithelial cell adhesion (PubMed:11772392). Colocalized with IGF2R in internalized cytoplasmic vesicles adjacent to the cell surface (PubMed:10900005). .
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Tissue Expression:
Expressed specifically in lymphatic vessels but not in blood vessels in the skin, small intestine, esophagus, ovary, breast and prostate glands. Not detected in lymphatic vessels in the lung, kidney, uterus, liver and stomach (at protein level). Expressed in the poorly differentiated crypt cells of the small intestine as well as in the mature villous cells. Expressed at very low levels in the colon.