Inhibition of ICE-related proteases (caspases) and nuclear apoptosis by phenylarsine oxide

Atsushi Takahashi, Pascal J. Goldschmidt-Clermont, Emad S. Alnemri, Teresa Fernandes-Alnemri, Kumiko Yoshizawa-Kumagaya, Kiichiro Nakajima, Masataka Sasada, Guy G. Poirier, William C. Earnshaw

Research output: Contribution to journalArticlepeer-review

33 Scopus citations


Biochemical analyses of nuclear apoptosis in vitro have revealed the existence of multiple active interleukin-1β-converting enzyme-related proteases (caspases) with distinct substrate recognition properties in extracts of preapoptotic chicken DU249 cells (S/M extracts). Previously we demonstrated that the activity of a caspase that cleaves lamins is required for the disintegration of nuclei in the late stages of apoptosis, despite the presence of a second active caspase that cleaves poly(ADP-ribose) polymerase (PARP). One simple explanation for this observation was that the lamin-cleaving caspase is sufficient to drive the nuclear events of apoptotic execution. Here, we report that phenylarsine oxide (PAO) inhibits the protease activities of recombinant human caspases as well as endogenous chicken caspases that are active in S/M extracts. PAO at 100 μM blocks the morphological changes of nuclear apoptosis in vitro and internucleosomal DNA fragmentation in S/M extracts without interfering with PARP or lamin A cleavage. Thus, lamin cleavage is not sufficient to drive the changes in nuclear morphology characteristic of apoptosis. Affinity labeling with YV(bio)KD-aomk shows that the degree of sensitivity to PAO differs among active caspases in S/M extracts. These results suggest that a PAO-sensitive caspase that is distinct from the PARP- or lamin-cleaving enzymes is required for the initiation of apoptotic morphological changes and for the activation of endonuclease(s). Taken together, our results suggest that two or more caspases are required for proteolytic events that are essential for the initiation and completion of nuclear apoptotic changes. The observation that PAO is an inhibitor of caspases and nuclear apoptotic events should be useful for the biochemical dissection of apoptosis in vitro and in vivo.

Original languageEnglish (US)
Pages (from-to)123-131
Number of pages9
JournalExperimental Cell Research
Issue number1
StatePublished - Feb 25 1997

ASJC Scopus subject areas

  • Cell Biology


Dive into the research topics of 'Inhibition of ICE-related proteases (caspases) and nuclear apoptosis by phenylarsine oxide'. Together they form a unique fingerprint.

Cite this