PMID:11067927

Citation	Chiravuri, M, Agarraberes, F, Mathieu, SL, Lee, H and Huber, BT (2000) Vesicular localization and characterization of a novel post-proline-cleaving aminodipeptidase, quiescent cell proline dipeptidase. J. Immunol. 165:5695-702
Abstract	A large number of chemokines, cytokines, and signal peptides share a highly conserved X-Pro motif on the N-terminus. The cleavage of this N-terminal X-Pro dipeptide results in functional alterations of chemokines such as RANTES, stroma-derived factor-1, and macrophage-derived chemokine. Until recently, CD26/DPPIV was the only known protease with the ability to cleave N-terminal X-Pro motifs at neutral pH. We have isolated and cloned a novel serine protease, quiescent cell proline dipeptidase (QPP), with substrate specificity similar to that of CD26/DPPIV. In this paper we show that QPP, like CD26/DPPIV, is synthesized with a propeptide and undergoes N:-glycosylation. Interestingly, this glycosylation is required for QPP enzymatic activity, but not for its localization. Unlike the cell surface molecule, CD26/DPPIV, QPP is targeted to intracellular vesicles that are distinct from lysosomes. Proteinase K treatment of intact vesicles indicates that QPP is located within the vesicles. These vesicles appear to have a secretory component, as QPP is secreted in a functionally active form in response to calcium release. The presence of QPP in the vesicular compartment suggests that molecules bearing the N-terminal X-Pro motif can be cleaved at multiple sites within and outside the cell. These results expand the potential site(s) and scope of a process that appears to be an important mechanism of post-translational regulation.
Links	PubMed
Keywords	Amino Acid Sequence; Carbohydrate Conformation; Cytoplasmic Vesicles/enzymology; Dipeptidases/biosynthesis; Dipeptidases/chemistry; Dipeptidases/metabolism; Dipeptidases/secretion; Enzyme Activation; Glycosylation; Humans; Hydrolysis; Interphase; Intracellular Fluid/enzymology; Jurkat Cells; Lysosomes/enzymology; Molecular Sequence Data; Proline/metabolism; Protein Processing, Post-Translational; Protein Sorting Signals; Serine Endopeptidases/biosynthesis; Serine Endopeptidases/chemistry; Serine Endopeptidases/metabolism; Serine Endopeptidases/secretion
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
HUMAN:DPP2		GO:0031982: vesicle	ECO:0000314:		C		figure 5 shows through confocal microscopy, localization of QPP (DPP2) to the vesicles.	complete CACAO 4029
HUMAN:DPP2	part_of	GO:0031982: vesicle	ECO:0000314: direct assay evidence used in manual assertion		C		Seeded From UniProt	complete

References

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