c-FLIPL regulates PKC via AP-2 to inhibit Bax-mediated apoptosis induced by HIV-1 gp120 in Jurkat cells

Article

Abstract

c-FLIPL, an inhibitor of caspase 8, is known to inhibit the Fas/caspase 8 apoptotic pathway; however, its involvement of Bax/mitochondrial apoptosis is not well understood. Using human cells, Jurkat cell line, induced with HIV-1 gp120, we studied the effects of c-FLIPL on Bax/mitochondrial apoptosis. We found that the induction of apoptosis by HIV-1 envelope protein, gp120, involved the activation of both Bax-dependent and death receptor-mediated pathways, and HIV-1 infection deceased c-FLIPL expression. Interestingly, c-FLIPL expression downregulated protein kinase C (PKC) expression at the transcript level involving activated protein-2 (AP-2). c-FLIPL expression reduced AP-2 protein levels required to promote PKC protein expression and PKC-associated inactive form of Bax, and inhibited Bax activation, suggesting that c-FLIPL inhibits Bax activation via modulating PKC expression at the transcriptional level involving AP-2 during gp120 treatment. Collectively, these findings further corroborate the concept that gp120 plays an important role, via involvement of molecules such as c-FLIPL, in apoptotic cell death due to HIV-1 infection.

Keywords

Apoptosis AP-2 HIV-1 gp120 c-FLIPL PKC Bax 

Notes

Acknowledgments

We thank Dr. Mingjie Zhang, Dr. Jinhai Wang and Dr. Hira Nakhasi for critical review of the manuscript. The findings and conclusions in this article have not been formally disseminated by the FDA and should not be construed to represent any agency determination or policy.

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Copyright information

© Springer Science+Business Media, LLC. 2009

Authors and Affiliations

  1. 1.Laboratory of Molecular Virology, Division of Emerging and Transfusion Transmitted Diseases Center for Biologics Evaluation and Research, Food and Drug AdministrationBethesdaUSA
  2. 2.Department of Pharmacology and Oncology and Lombardi Cancer CenterGeorgetown University School of MedicineWashingtonUSA

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