title: Glutathione binding to the Bcl-2 homology-3 domain groove: a molecular basis for Bcl-2 antioxidant function at mitochondria.
abstract: Bcl-2 protects cells against mitochondrial oxidative stress and subsequent apoptosis. However, the mechanism underlying the antioxidant function of Bcl-2 is currently unknown. Recently, Bax and several Bcl-2 homology-3 domain (BH3)-only proteins (Bid, Puma, and Noxa) have been shown to induce a pro-oxidant state at mitochondria (1-4). Given the opposing effects of Bcl-2 and Bax/BH3-only proteins on the redox state of mitochondria, we hypothesized that the antioxidant function of Bcl-2 is antagonized by its interaction with the BH3 domains of pro-apoptotic family members. Here, we show that BH3 mimetics that bind to a hydrophobic surface (the BH3 groove) of Bcl-2 induce GSH-sensitive mitochondrial dysfunction and apoptosis in cerebellar granule neurons. BH3 mimetics displace a discrete mitochondrial GSH pool in neurons and suppress GSH transport into isolated rat brain mitochondria. Moreover, BH3 mimetics and the BH3-only protein, Bim, inhibit a novel interaction between Bcl-2 and GSH in vitro. These results suggest that Bcl-2 regulates an essential pool of mitochondrial GSH and that this regulation may depend upon Bcl-2 directly interacting with GSH via the BH3 groove. We conclude that this novel GSH binding property of Bcl-2 likely plays a central role in its antioxidant function at mitochondria.
authors: Eleanor Roosevelt Institute, Department of Biological Sciences, University of Denver, Denver, Colorado 80208, USA.
authors: Angela K
authors: AK
authors: Zimmermann
authors: F Alexandra
authors: FA
authors: Loucks
authors: Emily K
authors: EK
authors: Schroeder
authors: Ron J
authors: RJ
authors: Bouchard
authors: Kenneth L
authors: KL
authors: Tyler
authors: Daniel A
authors: DA
authors: Linseman
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D017209:Apoptosis; D051023:BH3 Interacting Domain Death Agonist Protein / Q000737:chemistry*; D001921:Brain / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism; D009474:Neurons / Q000378:metabolism; D016877:Oxidants / Q000378:metabolism; D018384:Oxidative Stress; D011485:Protein Binding; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013481:Superoxides / Q000378:metabolism
chemical_list: D000975:Antioxidants; D051023:BH3 Interacting Domain Death Agonist Protein; C494816:Bid protein, rat; D016877:Oxidants; D019253:Proto-Oncogene Proteins c-bcl-2; D013481:Superoxides; D005978:Glutathione
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