Generation of active myeloid and lymphoid granule serine proteases requires processing by the granule thiol protease dipeptidyl peptidase I

• Published in: The Journal of biological chemistry Vol. 268; no. 4; pp. 2458 - 2467
• Main Authors: MCGUIRE, M. J, LIPSKY, P. E, THIELE, D. L
• Format: Journal Article
• Language: English
• Published: Bethesda, MD American Society for Biochemistry and Molecular Biology 05-02-1993
• Subjects: Amino Acid Sequence; Animals; Biological and medical sciences; Bone Marrow - enzymology; Cathepsin C; Cathepsin G; Cathepsins - metabolism; Cytoplasmic Granules - enzymology; Dipeptidyl-Peptidases and Tripeptidyl-Peptidases - antagonists & inhibitors; Dipeptidyl-Peptidases and Tripeptidyl-Peptidases - metabolism; Enzyme Activation; Fundamental and applied biological sciences. Psychology; Humans; In Vitro Techniques; Lymphocyte Activation; Lymphocytes - enzymology; Mice; Molecular and cellular biology; Molecular genetics; Molecular Sequence Data; Neutrophils - enzymology; Serine Endopeptidases - metabolism; Translation. Translation factors. Protein processing; Tumor Cells, Cultured; Vertebrata; Mammalia; Molecular processing; Enzymatic activity; Structure activity relation; Enzyme; Cytotoxicity; Dipeptidyl peptidase I; Serine proteinase; Lymphocyte
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/s0021-9258(18)53798-4

The proenzyme activation peptides predicted from cDNAs encoding each of the granule serine proteases synthesized by cytotoxic
lymphocytes and myeloid and mast cells are composed of 2 residues. The mechanism by which these amino-terminal dipeptides
are cleaved to generate the active enzymes has not been elucidated. The comparable distribution of dipeptidyl peptidase I
(DPPI) and serine proteases and the ability of DPPI to hydrolyze relevant dipeptide sequences suggested a role for DPPI in
the processing and activation of granule serine proteases. This study demonstrates that inhibition of DPPI activity is associated
with impairment of the generation of granule serine protease activity in CD8(+) T cells, lymphokine-activated killer cells,
P815 mastocytoma cells, and U-937 myeloid cells. Inhibition of DPPI resulted in impairment of the generation of cathepsin
G enzymatic activity without reduction in the amount of immunoreactive cathepsin G produced. In U-937 cells pulsed with [3H]isoleucine,
inhibition of DPPI activity was associated with the accumulation of the inactive proenzyme form of cathepsin G bearing an
amino-terminal dipeptide extension to the isoleucine residue that normally occupies the amino terminus of the enzymatically
active protein. These results indicate that DPPI plays a requisite role in the post-translational processing and activation
of members of the family of granule serine proteases expressed in bone marrow-derived effector cells.