ICE-LAP6, a Novel Member of the ICE/Ced-3 Gene Family, Is Activated by the Cytotoxic T Cell Protease Granzyme B

doi:10.1074/jbc.271.28.16720

ICE-LAP6, a Novel Member of the ICE/Ced-3 Gene Family, Is Activated by the Cytotoxic T Cell Protease Granzyme B*

From the Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan 48109
^§ Poly(ADP-Ribose) Metabolism Group, Department of Molecular Endocrinology, Centre Hospitalier de I'Universite Laval Research Center and Laval University, Sainte-Foy, QC Canada GIV 4G2
^¶ Department of Medicine, Evanston Hospital and Northwestern University Medical School, Evanston, Illinois 60201, and
^∥ Human Genome Sciences, Inc., Rockville, Maryland 20850-3338

” To whom correspondence should be addressed:
Dept. of Pathology, University of Michigan Medical School, 1301 Catherine St., Box 0602, Ann Arbor, MI 48109.
Tel.: 313-747-2921; Fax: 313-764-4308; E-mail: vmdixit{at}umich.edu.

Abstract

Members of the ICE/Ced-3 gene family are likely effector components of the cell death machinery. Here, we characterize a novel member of this family designated ICE-LAP6. By phylogenetic analysis, ICE-LAP6 is classified into the Ced-3 subfamily which includes Ced-3, Yama/CPP32/apopain, Mch2, and ICE-LAP3/Mch3/CMH-1. Interestingly, ICE-LAP6 contains an active site QACG pentapeptide, rather than the QACG pentapeptide shared by other family members. Overexpression of ICE-LAP6 induces apoptosis in MCF7 breast carcinoma cells. More importantly, ICE-LAP6 is proteolytically processed into an active cysteine protease by granzyme B, an important component of cytotoxic T cell-mediated apoptosis. Once activated, ICE-LAP6 is able to cleave the death substrate poly(ADP-ribose) polymerase into signature apoptotic fragments.

Footnotes

↵^‡ Fellow of the Medical Scientist Training Program, supported by the Experimental Immunopathology Training Grant.
↵* This work was supported in part by National Institutes of Health Grant CA64803. The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

The nucleotide sequence(s) reported in this paper has been submitted to the GenBank™/EMBL Data Bank with accession number(s) U56739[GenBank]0.
↵¹ The abbreviations used are:

ICE

interleukin-1β converting enzyme

PARP

poly(ADP-ribose) polymerase

PCR

polymerase chain reaction

ICE-LAP6

ICE-like apoptotic protease 6

PAGE

polyacylamide gel electrophoresis

X-gal

5-bromo-4-chloro-3-indoyl β-[d-galactoside

CHAPS

3-[(3-cholamidopropyl)dimethylammonio]-1-propanesufonic acid.
- Received April 25, 1996.