Molecular and Cellular Biology, July 2001, p. 4292-4301, Vol. 21, No. 13
0270-7306/01/$04.00+0 DOI: 10.1128/MCB.21.13.4292-4301.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.

Metabolism Branch, Division of Clinical Sciences, National
Cancer Institute,1 and Surgical
Neurology Branch, National Institute of Neurological Disorders and
Stroke,3 National Institutes of Health,
Bethesda, and National Cancer Institute
Frederick Cancer
Research and Development Center, National Institutes of Health,
Frederick,5 Maryland, and Istituto
Tecnologie Biomediche Avanzate, Milan,2 and
Department of Pediatrics, University of Brescia,
Brescia,4 Italy
Received 21 December 2000/Returned for modification 12 February 2001/Accepted 2 April 2001
Inhibitor of apoptosis protein (IAP)-like protein-1 (ILP-1) (also known as X-linked IAP [XIAP] and mammalian IAP homolog A [MIHA]) is a potent inhibitor of apoptosis and exerts its effects, at least in part, by the direct association with and inhibition of specific caspases. Here, we describe the molecular cloning and characterization of a human gene related to ILP-1, termed ILP-2. Despite high homology to ILP-1, ILP-2 is encoded by a distinct gene, which in normal tissues is expressed solely in testis. In contrast to ILP-1, overexpression of ILP-2 had no protective effect on apoptosis mediated by Fas (also known as CD95) or tumor necrosis factor. However, ILP-2 potently inhibited apoptosis induced by overexpression of Bax or by coexpression of caspase 9 with Apaf-1, and preincubation of cytosolic extracts with ILP-2 abrogated caspase activation in vitro. A processed form of caspase 9 could be coprecipitated with ILP-2 from cells, suggesting a physical interaction between ILP-2 and caspase 9. Thus, ILP-2 is a novel IAP family member with restricted specificity for caspase 9.
This paper is dedicated to the memory of Lois K. Miller. This is
manuscript no. 45 of the Genoma 2000/ITBA Project funded by Cariplo.
This article has been cited by other articles:
| J. Bacteriol. | J. Virol. | Eukaryot. Cell |
|---|
| Microbiol. Mol. Biol. Rev. | Clin. Vaccine Immunol. | All ASM Journals |
|---|