Disease relevance of Dpp7

• The purpose of this study was to quantitate biochemically and to localize histochemically the proteases cathepsin B (Cath B), dipeptidyl peptidase I (DPP I), and dipeptidyl peptidase II (DPP II) in experimental pulmonary granulomatosis and fibrosis [1].

High impact information on Dpp7

• In control animals, electron-dense reaction product representing Dpp II activity was observed in lysosomes, lipofuscin granules, short cisternae located close to the granular endoplasmic reticulum, and dense granules [2].
• Dpp II-containing organelles were localized mainly to the cell body and were randomly distributed in the perikaryal cytoplasm [2].
• The effect of colchicine injections on the ultrastructural localization of dipeptidyl peptidase II (Dpp II) was studied in the mitral cells of the rat olfactory bulb [2].
• Injection of colchicine into the lateral cerebral ventricle of the rat was found to induce a paradoxical translocation of two lysosomal enzymes, dipeptidyl peptidase II (Dpp II) and acid phosphatase, from the soma of neurons to the dendrites [3].
• Dipeptidyl aminopeptidase II (DAP II) was demonstrated cytochemically in rat peritoneal mast cells [4].

Biological context of Dpp7

• The heterophagic granules of mast cells: dipeptidyl aminopeptidase II activity and resistance to exocytosis [4].
• The increase of DPP II activity is dose- and time-dependent and can also be elicited by the second messenger cAMP [5].
• Macrophage DAP II was found to be typical of that found in other rat tissues in terms of its structural latency, substrate specificity, inhibitor sensitivities, and pH activator requirements [6].
• The axonal transport of dipeptidyl aminopeptidase II, angiotensin-converting enzyme and other peptidases in rat sciatic nerves [7].
• We propose that DPP II may have a role in programmed cell death which is thought to occur in this transition zone [8].

Anatomical context of Dpp7

• Areas in the brain with high densities of DAP II staining include the mitral cells in the olfactory bulb, polymorphic cells in the hippocampus, the paraventricular nucleus of the hypothalamus, and the anterior dorsal thalamus, Purkinje cells, and deep nuclei in the cerebellum [9].
• In mast cells exposed 1 to 2 hours to phosphate-buffered saline containing horseradish-peroxidase--coated colloidal gold, the spherules of gold were internalized and transported exclusively to the DAP II-reactive granules [4].
• Focal areas in the nuclear envelope densified by DAP II reaction product resembled reactive foci observed previously in the nuclear envelope of peritoneal macrophages [4].
• Purified rat peritoneal mast cells have a 10-20-fold higher dipeptidyl peptidase II (DPP II) activity as compared with that of macrophages from the same source [10].
• The bulk activity of DPP II in immature rat brains is attributed to differentiating astrocytes loosing it in later postnatal stages due to a neuronal influence [5].

Associations of Dpp7 with chemical compounds

• Mast cells induced to release their granules by stimulation with the divalent cation ionophore A23187 retained exclusively those granules possessing DAP II or acid phosphatase reactivity [4].
• Both histamine and Zn2+, two ingredients of mast-cell granules, strongly inhibit DPP II at concentrations reported to occur in the granules [10].
• Upon stimulation with the secretagogue Compound 48/80, DPP II is released from peritoneal-lavage cells and from purified mast cells, but not from purified macrophages, in a dose-dependent manner [10].
• Arylamidase, dipeptidyl peptidase III and most of the leucine aminopeptidase could be extracted from the muscle with a neutral salt solution, but dipeptidyl peptidase I was extracted only in the presence of Triton X-100; dipeptidyl peptidase II showed an intermediate extraction behaviour [11].
• Cytochemical localization and biochemical evaluation of a lysosomal serine protease in lung: dipeptidyl peptidase II in the normal rat [12].

Regulatory relationships of Dpp7

• Transforming growth factor beta 1 and parathyroid hormone-related protein control the secretion of dipeptidyl peptidase II by rat astrocytes [13].

Other interactions of Dpp7

• Cathepsin B and dipeptidyl peptidase I were localized primarily in subsarcolemmal regions whereas cathepsin H and dipeptidyl peptidase II were scattered throughout the sarcoplasm consistent with other observation of two populations of muscle lysosomes [14].
• Histochemical localization of cathepsin B, dipeptidyl peptidase I, and dipeptidyl peptidase II in rat bone [15].
• It is assumed that DPP II influences the course of cicatrization after penetrating injuries of the brain and thus, meninges control glial scarring by the release of TGF beta 1 and PTHrP [13].
• Astrocytes are significantly enriched in post-proline cleaving dipeptidyl peptidase II, prolidase and aminopeptidase P activities; neurones and astrocytes contain prolyl endopeptidase [16].
• PTHrP itself has no effect on the release of DPP II activity but considerably reduces the effect of TGF beta 1 [13].

Analytical, diagnostic and therapeutic context of Dpp7

• Maximally, about one-third of the DPP II present in peritoneal-lavage cells is released [10].
• Electron microscopy shows the subcellular localization of DAP-II to be limited to lytic bodies and in mammotrophic cells to some secretion granules [17].
• First attempts are reported to quantitate acid phosphatase (AcPase) and dipeptidyl aminopeptidase II (DAP-II) in monodispersed anterior pituitary cells from lactating and postlactating rats by flow cytometry, fluorescent, and electron microscopy [17].
• DAP II was further characterized by isoelectric focusing techniques [6].
• At 2 days after ligation, rapid retrograde axonal transport of the activity of dipeptidyl aminopeptidase II (a lysosomal enzyme), angiotensin-converting enzyme and leucyl aminopeptidase (membrane-bound enzymes), was found in the segment distal to the proximal ligation [7].

References