A Death Receptor-associated Anti-apoptotic Protein, BRE, Inhibits Mitochondrial Apoptotic Pathway

• Published in: The Journal of biological chemistry Vol. 279; no. 50; pp. 52106 - 52116
• Main Authors: Li, Qing, Ching, Arthur Kar-Keung, Chan, Ben Chung-Lap, Chow, Stephanie Ka-Yee, Lim, Pak-Leong, Ho, Tony Cheong-Yip, Ip, Wai-Ki, Wong, Chun-Kwok, Lam, Christopher Wai-Kei, Lee, Kenneth Ka-Ho, Chan, John Yeuk-Hon, Chui, Yiu-Loon
• Format: Journal Article
• Language: English
• Published: United States American Society for Biochemistry and Molecular Biology 10.12.2004
• Subjects: Apoptosis - drug effects; Apoptosis - physiology; Base Sequence; Cell Nucleus - metabolism; Cycloheximide - pharmacology; Cytosol - metabolism; Etoposide - pharmacology; fas Receptor - metabolism; Gene Expression; HeLa Cells; Humans; Jurkat Cells; Mitochondria - metabolism; Nerve Tissue Proteins - genetics; Nerve Tissue Proteins - physiology; Receptors, Tumor Necrosis Factor, Type I - metabolism; Recombinant Proteins - genetics; Recombinant Proteins - metabolism; RNA, Small Interfering - genetics; Transfection; Tumor Necrosis Factor-alpha - pharmacology
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M408678200

BRE, b rain and r eproductive organ- e xpressed protein, was found previously to bind the intracellular juxtamembrane domain of a ubiquitous death receptor, tumor necrosis factor receptor 1 (TNF-R1), and to down-regulate TNF-α-induced activation of NF-κB. Here we show that BRE also binds to another death receptor, Fas, and upon overexpression conferred resistance to apoptosis induced by TNF-α, anti-Fas agonist antibody, cycloheximide, and a variety of stress-related stimuli. However, down-regulation of the endogenous BRE by small interfering RNA increased apoptosis to TNF-α, but nottoetoposide, indicating that the physiological antiapoptotic role of this protein is specific to death receptor-mediated apoptosis. We further demonstrate that BRE mediates antiapoptosis by inhibiting the mitochondrial apoptotic machinery but without translocation to the mitochondria or nucleus or down-regulation of the cellular level of truncated Bid. Dissociation of BRE rapidly from TNF-R1, but not from Fas, upon receptor ligation suggests that this protein interacts with the death inducing signaling complex during apoptotic induction. Increased association of BREwith phosphorylated, sumoylated, and ubiquitinated proteins after death receptor stimulation was also detected. We conclude that in contrast to the truncated Bid that integrates mitochondrial apoptosis to death receptor-triggered apoptotic cascade, BRE inhibits the integration. We propose that BRE inhibits, by ubiquitination-like activity, components in or proximal to the death-inducing signaling complexes that are necessary for activation of the mitochondria.