A Bcl-2 homolog encoded by Kaposi sarcoma-associated virus, human herpesvirus 8, inhibits apoptosis but does not heterodimerize with Bax or Bak Academic Article Article uri icon


MeSH Major

  • Apoptosis
  • Apoptosis Regulatory Proteins
  • Carcinoma, Non-Small-Cell Lung
  • Drug Resistance, Neoplasm
  • Leukemia, Myelogenous, Chronic, BCR-ABL Positive
  • Lung Neoplasms
  • Membrane Proteins
  • Polymorphism, Genetic
  • Protein Kinase Inhibitors
  • Proto-Oncogene Proteins
  • Sequence Deletion


  • The Bcl-2 protein family is characterized by the ability to modulate cell death, and members of this family share two highly conserved domains called Bcl-2 homology 1 (BH1) and 2 (BH2) which have been shown to be critical for the death-repressor activity of Bcl-2 and Bcl-xL. Through sequence analysis we identified a novel viral Bcl-2 homolog, designated KSbcl-2, from human herpesvirus 8 (HHV8) or Kaposi sarcoma-associated herpesvirus. The overall amino acid sequence identity between KSbcl-2 and other Bcl-2 homologs is low (15-20%) but concentrated within the BH1 and BH2 regions. Overexpression of KSbcl-2 blocked apoptosis as efficiently as Bcl-2, Bcl-xL, or another viral Bcl-2 homolog encoded by Epstein-Barr virus, BHRF1. Interestingly, KS-bcl-2 neither homodimerizes nor heterodimerizes with other Bcl-2 family members, suggesting that KSbcl-2 may have evolved to escape any negative regulatory effects of the cellular Bax and Bak proteins. Furthermore, the herpesvirus Bcl-2 homologs including KSbcl-2, BHRF1, and ORF16 of herpesvirus saimiri contain poorly conserved Bcl-2 homology 3 (BH3) domains compared with other mammalian Bcl-2 homologs, implying that BH3 may not be essential for anti-apoptotic function. This is consistent with our observation that amino acid substitutions within the BH3 domain of Bcl-xL had no effect on its death-suppressor activity.

publication date

  • January 21, 1997



  • Academic Article


Digital Object Identifier (DOI)

  • 10.1073/pnas.94.2.690

PubMed ID

  • 9012846

Additional Document Info

start page

  • 690

end page

  • 4


  • 94


  • 2