Please use this identifier to cite or link to this item: http://hdl.handle.net/2381/24122
Title: Processing/activation of at least four interleukin-1β converting enzyme-like proteases occurs during the execution phase of apoptosis in human monocytic tumor cells
Authors: MacFarlane, Marion
Cain, Kelvin
Sun, Xiao-Ming
Alnemri, E. S.
Cohen, Gerald M.
First Published: 21-Apr-1997
Publisher: Rockefeller University Press
Citation: Journal of Cell Biology, 1997, 137 (2), pp. 469-479
Abstract: Identification of the processing/activation of multiple interleukin-1β converting enzyme (ICE)–like proteases and their target substrates in the intact cell is critical to our understanding of the apoptotic process. In this study we demonstrate processing/activation of at least four ICE-like proteases during the execution phase of apoptosis in human monocytic tumor THP.1 cells. Apoptosis was accompanied by processing of Ich-1, CPP32, and Mch3α to their catalytically active subunits, and lysates from these cells displayed a proteolytic activity with kinetics, characteristic of CPP32/Mch3α but not of ICE. Fluorescence-activated cell sorting was used to obtain pure populations of normal and apoptotic cells. In apoptotic cells, extensive cleavage of Ich-1, CPP32, and Mch3α was observed together with proteolysis of the ICE-like protease substrates, poly (ADP-ribose) polymerase (PARP), the 70-kD protein component of U1 small nuclear ribonucleoprotein (U170K), and lamins A/B. In contrast, no cleavage of CPP32, Mch3α or the substrates was observed in normal cells. In cells exposed to an apoptotic stimulus, some processing of Ich-1 was detected in morphologically normal cells, suggesting that cleavage of Ich-1 may occur early in the apoptotic process. The ICE-like protease inhibitor, benzyloxycarbonyl-Val-Ala-Asp (OMe) fluoromethyl ketone (Z-VAD.FMK), inhibited apoptosis and cleavage of Ich-1, CPP32, Mch3α, Mch2α, PARP, U1-70K, and lamins. These results suggest that Z-VAD.FMK inhibits apoptosis by inhibiting a key effector protease upstream of Ich-1, CPP32, Mch3α, and Mch2α. Together these observations demonstrate that processing/activation of Ich-1, CPP32, Mch3α, and Mch2α accompanies the execution phase of apoptosis in THP.1 cells. This is the first demonstration of the activation of at least four ICE-like proteases in apoptotic cells, providing further evidence for a requirement for the activation of multiple ICE-like proteases during apoptosis.
DOI Link: 10.1083/jcb.137.2.469
ISSN: 0021-9525
Links: http://hdl.handle.net/2381/24122
http://jcb.rupress.org/content/137/2/469
Type: Journal Article
Rights: © 1997 Rockefeller University Press CC BY-NC-SA
Appears in Collections:Published Articles, Dept. of Biochemistry



Items in LRA are protected by copyright, with all rights reserved, unless otherwise indicated.