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J Biol Chem. 1999 Feb 12;274(7):3988-93.

Truncation of macrophage-derived chemokine by CD26/ dipeptidyl-peptidase IV beyond its predicted cleavage site affects chemotactic activity and CC chemokine receptor 4 interaction.

Author information

1
Laboratory of Molecular Immunology, Rega Institute for Medical Research, University of Leuven, Minderbroedersstraat 10, B-3000 Leuven, Belgium. Paul.Proost@rega.kuleuven.ac.be

Abstract

The serine protease CD26/dipeptidyl-peptidase IV (CD26/DPP IV) and chemokines are known key players in immunological processes. Surprisingly, CD26/DPP IV not only removed the expected Gly1-Pro2 dipeptide from the NH2 terminus of macrophage-derived chemokine (MDC) but subsequently also the Tyr3-Gly4 dipeptide, generating MDC(5-69). This second cleavage after a Gly residue demonstrated that the substrate specificity of this protease is less restricted than anticipated. The unusual processing of MDC by CD26/DPP IV was confirmed on the synthetic peptides GPYGANMED (MDC(1-9)) and YGANMED (MDC(3-9)). Compared with intact MDC(1-69), CD26/DPP IV-processed MDC(5-69) had reduced chemotactic activity on lymphocytes and monocyte-derived dendritic cells, showed impaired mobilization of intracellular Ca2+ through CC chemokine receptor 4 (CCR4), and was unable to desensitize for MDC-induced Ca2+-responses in CCR4 transfectants. However, MDC(5-69) remained equally chemotactic as intact MDC(1-69) on monocytes. In contrast to the reduced binding to lymphocytes and CCR4 transfectants, MDC(5-69) retained its binding properties to monocytes and its anti-HIV-1 activity. Thus, NH2-terminal truncation of MDC by CD26/DPP IV has profound biological consequences and may be an important regulatory mechanism during the migration of Th2 lymphocytes and dendritic cells to germinal centers and to sites of inflammation.

PMID:
9933589
DOI:
10.1074/jbc.274.7.3988
[Indexed for MEDLINE]
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