N-terminal proteolytic processing by cathepsin G converts RANTES/CCL5 and related analogs into a truncated 4-68 variant.
N-terminal proteolytic processing modulates the biological activity and receptor specificity of RANTES/CCL5. Previously, we showed that an unidentified protease associated with monocytes and neutrophils digests RANTES into a variant lacking three N-terminal residues (4-68 RANTES). This variant binds CCR5 but exhibits lower chemotactic and antiviral activities than unprocessed RANTES. In this study, we characterize cathepsin G as the enzyme responsible for this processing. Cell-mediated production of the 4-68 variant was abrogated by Eglin C, a leukocyte elastase and cathepsin G inhibitor, but not by the elastase inhibitor elastatinal. Further, anti-cathepsin G antibodies abrogated RANTES digestion in neutrophil cultures. In accordance, reagent cathepsin G specifically digested recombinant RANTES into the 4-68 variant. AOP-RANTES and Met-RANTES were also converted into the 4-68 variant upon exposure to cathepsin G or neutrophils, while PSC-RANTES was resistant to such cleavage. Similarly, macaque cervicovaginal lavage samples digested Met-RANTES and AOP-RANTES, but not PSC-RANTES, into the 4-68 variant and this processing was also inhibited by anti-cathepsin G antibodies. These findings suggest that cathepsin G mediates a novel pathway for regulating RANTES activity and may be relevant to the role of RANTES and its analogs in preventing HIV infection.
Lim
Jean K
JK
Institute of Human Virology, University of Maryland, Baltimore, 725 W. Lombard Street, 6th fl., Baltimore, MD 21201, USA.
Lu
Wuyuan
W
Hartley
Oliver
O
DeVico
Anthony L
AL
D000906:Antibodies / Q000494:pharmacology; D000998:Antiviral Agents / Q000378:metabolism / Q000494:pharmacology / Q000627:therapeutic use; D056649:Cathepsin G; D002403:Cathepsins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D018946:Chemokine CCL5 / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology / Q000627:therapeutic use; D002633:Chemotaxis / Q000187:drug effects; D015658:HIV Infections / Q000378:metabolism* / Q000517:prevention & control; D006801:Humans; D009504:Neutrophils / Q000201:enzymology*; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D011506:Proteins / Q000494:pharmacology; D019713:Receptors, CCR5 / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism / Q000494:pharmacology / Q000627:therapeutic use; D012697:Serine Endopeptidases / Q000378:metabolism*; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology
D000906:Antibodies; D000998:Antiviral Agents; D018946:Chemokine CCL5; D011506:Proteins; C108335:RANTES, Met-; D019713:Receptors, CCR5; D011994:Recombinant Proteins; D015842:Serine Proteinase Inhibitors; C111989:aminooxypentane-RANTES; C028656:eglin proteinase inhibitors; D002403:Cathepsins; D012697:Serine Endopeptidases; C534094:CTSG protein, human; D056649:Cathepsin G