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FADD is Initially Located in the Mitochondria in TNF Mediated Apoptosis in Rat Hepatocytes
Author(s) -
Vallabhaneni Raghuveer,
Guo Fengli,
Zhang XiaoYing,
Crissman Sara,
Mollen Kevin Patrick,
Yuan Youzhong,
Stolz Donna Beer,
Billiar Timothy R.
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.a1462
Subject(s) - fadd , death domain , mitochondrion , microbiology and biotechnology , apoptosis , programmed cell death , tumor necrosis factor alpha , biology , cytosol , western blot , chemistry , caspase , immunology , biochemistry , gene , enzyme
Tumor necrosis factor‐α (TNF) is an important cytokine in inflammation and cell death signaling. There has been much interest in elucidating the mechanisms of TNF‐mediated apoptotic cell death. Although much has been discovered about the components of the Death Induced Signaling Complex (DISC), the subcellular localization of these proteins is unclear. Fas‐Associated Death Domain Protein (FADD) is an essential component of death‐receptor mediated apoptosis. Hepatocytes undergo apoptosis through a mitochondrial dependent pathway. We hypothesized that FADD is located in the mitochondria. Sprague‐Dawley rats were used to obtain primary hepatocyte cultures. These cells were treated with TNF and Actinomycin D (A) to induce apoptosis. Mitochondrial fractions were obtained and Western Blot was performed with FADD antibody. FADD was present in the mitochondria at baseline, but was diminished at 1 hr treatment with TNF/A. Immunoelectron microscopy was then performed labeling the samples with FADD antibody and then labeling with a gold linked secondary antibody. In untreated cells, FADD was mainly located in the mitochondria. FADD left the mitochondria after 1 hr treatment with TNF/A. This is the first time that FADD protein has been located to the mitochondria. Our data suggests that there may be a shuttling mechanism from the mitochondria to the cytosolic compartment once TNF mediated apoptosis is induced in rat hepatocytes.