The HIV-1-specific protein Casp8p41 induces death of infected cells through Bax/Bak

Amy M. Sainski, Sekar Natesampillai, Nathan W Cummins, Gary D. Bren, Julie Taylor, Dyana T. Saenz, Eric M. Poeschla, Andrew David Badley

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

Casp8p41, a novel protein generated when HIV-1 protease cleaves caspase 8, independently causes NF-κB activation, proinflammatory cytokine production, and cell death. Here we investigate the mechanism by which Casp8p41 induces cell death. Immunogold staining and electron microscopy demonstrate that Casp8p41 localizes to mitochondria of activated primary CD4 T cells, suggesting mitochondrial involvement. Therefore, we assessed the dependency of Casp8p41-induced death on Bax/Bak and caspase 9. In wild-type (WT) mouse embryonic fibroblast (MEF) cells, Casp8p41 causes rapid mitochondrial depolarization (P < 0.001), yet Casp8p41 expression in Bax/Bak double-knockout (DKO) MEF cells does not. Similarly, caspase 9-deficient T cells (JMR cells), which express Casp8p41, undergo minimal cell death, whereas reconstituting these cells with caspase 9 (F9 cells) restores Casp8p41 cytotoxicity (P < 0.01). The infection of caspase 9-deficient cells with a green fluorescent protein (GFP) HIV-1 reporter virus results in cell death in 32% of infected GFP-positive cells, while the restoration of caspase 9 expression in these cells restores infected-cell killing to 68% (P < 0.05), with similar levels of viral replication between infections. Our data demonstrate that Casp8p41 requires Bax/Bak to induce mitochondrial depolarization, which leads to caspase 9 activation following either Casp8p41 expression or HIV-1 infection. This understanding allows the design of strategies to interrupt this form of death of HIV-1-infected cells.

Original languageEnglish (US)
Pages (from-to)7965-7975
Number of pages11
JournalJournal of Virology
Volume85
Issue number16
DOIs
StatePublished - Aug 2011

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Human immunodeficiency virus 1
caspase-9
HIV-1
cell death
Cell Death
Caspase 9
Proteins
proteins
cells
green fluorescent protein
fibroblasts
Green Fluorescent Proteins
T-lymphocytes
infection
death
caspase-8
Fibroblasts
mice
T-Lymphocytes
virus replication

ASJC Scopus subject areas

  • Immunology
  • Virology

Cite this

The HIV-1-specific protein Casp8p41 induces death of infected cells through Bax/Bak. / Sainski, Amy M.; Natesampillai, Sekar; Cummins, Nathan W; Bren, Gary D.; Taylor, Julie; Saenz, Dyana T.; Poeschla, Eric M.; Badley, Andrew David.

In: Journal of Virology, Vol. 85, No. 16, 08.2011, p. 7965-7975.

Research output: Contribution to journalArticle

Sainski, AM, Natesampillai, S, Cummins, NW, Bren, GD, Taylor, J, Saenz, DT, Poeschla, EM & Badley, AD 2011, 'The HIV-1-specific protein Casp8p41 induces death of infected cells through Bax/Bak', Journal of Virology, vol. 85, no. 16, pp. 7965-7975. https://doi.org/10.1128/JVI.00280-11
Sainski, Amy M. ; Natesampillai, Sekar ; Cummins, Nathan W ; Bren, Gary D. ; Taylor, Julie ; Saenz, Dyana T. ; Poeschla, Eric M. ; Badley, Andrew David. / The HIV-1-specific protein Casp8p41 induces death of infected cells through Bax/Bak. In: Journal of Virology. 2011 ; Vol. 85, No. 16. pp. 7965-7975.
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