A collagen-binding glycoprotein on the surface of mouse fibroblasts is identified as dipeptidyl peptidase IV

Abstract

A dipeptidyl aminopeptidase (DPP) was detected in plasma membranes from normal (3T3) and transformed (3T12) mouse fibroblasts. This enzyme was active in cleaving the prolyl bond in the synthetic dipeptide nitroanilide Gly-Pro-NH-Np, which is a specific substrate for DPP IV (Km 0.63 mM and Vmax 6.1 nmol/min per mg at pH 6.0 and 37 degrees C). However, it did not degrade Pro-NH-Np or other dipeptide nitroanilides such as Gly-Arg-NH-Np or Val-Ala-NH-Np. The enzyme was totally inhibited by di-isopropyl phosphorofluoridate (Pri2-P-F) and by phenylmethanesulphonyl fluoride, indicating a serine catalytic site for the proteinase. DPP IV is a glycoprotein that specifically recognized immobilized gelatin and type I collagen. Upon molecular exclusion chromatography, the proteinase exhibited an apparent Mr of 100,000. SDS/polyacrylamide-gel electrophoresis under non-reducing and reducing conditions revealed that the [3H]Pri2-P-protein was exclusively represented by a polypeptide of Mr 55,000. This suggested that DPP IV consists of two non-covalently linked 55,000-Mr subunits. Fibroblast adhesion to native or denatured collagen was significantly inhibited by the two dipeptide inhibitors of DPP IV, Gly-Pro-Ala and Ala-Pro-Gly, but not by the peptides Gly-Pro and Gly-Gly-Gly, which are not inhibitors of the proteinase. Moreover, preliminary fractionation of DPP IV by molecular exclusion chromatography and affinity chromatography indicated that this material was active in disrupting cell adhesion to collagens. Taken together, the above data suggest that a fibroblast membrane-associated collagen-binding glycoprotein, DPP IV, may play a role in cell attachment to collagen.

Regulation of Fibroblast Migration on Collagenous Matrix by a Cell Surface Peptidase Complex

“…Role in Cell Adhesion-As DPPIV was shown to be an adhesion receptor for collagen (15)(16)(17) or fibronectin (18 -20), we have examined whether the inhibitory effect of mAb E19 (against DPPIV) on cellular migration in collagen gels and on gelatin degradation by migratory cells was due to its influence on adhesion activity. In a parallel comparison to integrin adhesion to collagen fibers, whereas mAb E19 (against DPPIV) inhibits cellular migration in collagen gels and gelatin degradation by migratory cells, it does not affect WI38 cell spreading on type I collagen substratum and attachment to collagen substratum (data not shown).…”

“…DPPIV and seprase are type II transmembrane proteins, with cytoplasmic tails that contain 6 amino acids (aa) followed by a 20-(seprase) or 22-aa (DPPIV) transmembrane domain at the N terminus and a stretch of 200 aa at the C terminus that constitutes a catalytic region with the catalytic serine in a non-classical orientation as compared with serine proteinases such as trypsin and chymotrypsin (13,14). DPPIV has binding capability for collagen (15)(16)(17) and fibronectin (18 -20). In addition, a recent report (21) showed that DPPIV also possesses a seprase-like gelatinase activity and therefore endopeptidase activity, suggesting its involvement in gelatin degradation.…”

Dipeptidyl Peptidase Inhibits Malignant Phenotype of Prostate Cancer Cells by Blocking Basic Fibroblast Growth Factor Signaling Pathway

“…Its proteolytic activity leads to inactivation or degradation of these peptides (7,8). DPPIV is involved in diverse biological processes, including cell differentiation, adhesion, immunomodulation, and apoptosis, functions that are critical for controlling neoplastic transformation (7)(8)(9)(10)(11)(12)(13). DPPIV is expressed in normal epithelial cells and melanocytes (11)(12)(13)(14)(15).…”

Occupancy of dipeptidyl peptidase IV activates an associated tyrosine kinase and triggers an apoptotic signal in human hepatocarcinoma cells

“…20 Among the best candidates as physiological substrates are the neuropeptide substance P 21 and several cytokines, such as IL-1, IL-2, and IL-6. 20 Evidence indicates that CD26 may interact with extracellular matrix proteins, [22][23][24][25] suggesting that this molecule is in some way involved in the tissue remodeling process. Most of the functional properties of CD26, and its intermolecular connections, have been elucidated in T lymphocytes, in which CD26 is up-regulated during cell activation.…”