Antiapoptotic herpesvirus Bcl-2 homologs escape caspase-mediated conversion to proapoptotic proteins

Bellows, D. S., Chau, B. N., Lee, P., Lazebnik, Y., Burns, W. H., Hardwick, J. M. (2000) Antiapoptotic herpesvirus Bcl-2 homologs escape caspase-mediated conversion to proapoptotic proteins. Journal of Virology, 74 (11). pp. 5024-5031. ISSN 0022-538X

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URL: http://www.ncbi.nlm.nih.gov/pubmed/10799576
DOI: 10.1128/​JVI.74.11.5024-5031.2000

Abstract

The antiapoptotic Bcl-2 and Bcl-x(L) proteins of mammals are converted into potent proapoptotic factors when they are cleaved by caspases, a family of apoptosis-inducing proteases (E. H.-Y. Cheng, D. G. Kirsch, R. J. Clem, R. Ravi, M. B. Kastan, A. Bedi, K. Ueno, and J. M. Hardwick, Science 278:1966-1968, 1997; R. J. Clem, E. H.-Y. Cheng, C. L. Karp, D. G. Kirsch, K. Ueno, A. Takahashi, M. B. Kastan, D. E. Griffin, W. C. Earnshaw, M. A. Veliuona, and J. M. Hardwick, Proc. Natl. Acad. Sci. USA 95:554-559, 1998). Gamma herpesviruses also encode homologs of the Bcl-2 family. All tested herpesvirus Bcl-2 homologs possess antiapoptotic activity, including the more distantly related homologs encoded by murine gammaherpesvirus 68 (gammaHV68) and bovine herpesvirus 4 (BHV4), as described here. To determine if viral Bcl-2 proteins can be converted into death factors, similar to their cellular counterparts, five herpesvirus Bcl-2 homologs from five different viruses were tested for their susceptibility to caspases. Only the viral Bcl-2 protein encoded by gammaHV68 was susceptible to caspase digestion. However, unlike the caspase cleavage products of cellular Bcl-2, Bcl-x(L), and Bid, which are potent inducers of apoptosis, the cleavage product of gammaHV68 Bcl-2 lacked proapoptotic activity. KSBcl-2, encoded by the Kaposi's sarcoma-associated herpesvirus, was the only viral Bcl-2 homolog that was capable of killing cells when expressed as an N-terminal truncation. However, because KSBcl-2 was not cleavable by caspases, the latent proapoptotic activity of KSBcl-2 apparently cannot be released. The Bcl-2 homologs encoded by herpesvirus saimiri, Epstein-Barr virus, and BHV4 were not cleaved by apoptotic cell extracts and did not possess latent proapoptotic activities. Thus, herpesvirus Bcl-2 homologs escape negative regulation by retaining their antiapoptotic activities and/or failing to be converted into proapoptotic proteins by caspases during programmed cell death.

Item Type: Paper
Uncontrolled Keywords: Amino Acid Sequence Animals Apoptosis Binding Sites Caspases Cattle Cell Line Cricetinae Gammaherpesvirinae Humans Mice Molecular Sequence Data Protein Precursors Proto-Oncogene Proteins c-bcl-2 Sequence Homology, Amino Acid Viral Proteins
Subjects: organs, tissues, organelles, cell types and functions > cell types and functions > cell functions > apoptosis
organs, tissues, organelles, cell types and functions > cell types and functions > cell functions
organs, tissues, organelles, cell types and functions > cell types and functions
CSHL Authors:
Communities: CSHL labs > Labeznik lab
Depositing User: Matt Covey
Date: 2000
Date Deposited: 12 Dec 2012 17:31
Last Modified: 12 Dec 2012 17:31
PMCID: PMC110854
Related URLs:
URI: http://repository.cshl.edu/id/eprint/26392

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