Skip directly to search Skip directly to A to Z list Skip directly to page options Skip directly to site content

NIOSHTIC-2 Publications Search

Search Results

S-nitrosylation of Bcl-2 inhibits its ubiquitin-proteasomal degradation - a novel antiapoptotic mechanism that suppresses apoptosis.

Authors
Azad-N; Vallyathan-V; Wang-LY; Tantishaiyakul-V; Stehlik-C; Leonard-SS; Rojanasakul-Y
Source
J Biol Chem 2006 Nov; 281(45):34124-34134
NIOSHTIC No.
20031218
Abstract
Bcl-2 is a key apoptosis regulatory protein of the mitochondrial death pathway whose function is dependent on its expression levels. Although Bcl-2 expression is controlled by various mechanisms, post-translational modifications, such as ubiquitination and proteasomal degradation, have emerged as important regulators of Bcl-2 function. However, the underlying mechanisms of this regulation are unclear. We report here that Bcl-2 undergoes S-nitrosylation by endogenous nitric oxide (NO) in response to multiple apoptotic mediators and that this modification inhibits ubiquitin-proteasomal degradation of Bcl-2. Inhibition of NO production by the NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide and by NO synthase inhibitor aminoguanidine effectively inhibited S-nitrosylation of Bcl-2, increased its ubiquitination, and promoted apoptotic cell death induced by chromium (VI). In contrast, the NO donors dipropylenetriamine NONOate and sodium nitroprusside showed opposite effects. The effect of NO on Bcl-2 stability was shown to be independent of its dephosphorylation. Mutational analysis of Bcl-2 further showed that the two cysteine residues of Bcl-2 (Cys(158) and Cys(229)) are important in the S-nitrosylation process and that mutations of these cysteines completely inhibited Bcl-2 S-nitrosylation. Treatment of the cells with other stress inducers, including Fas ligand and buthionine sulfoxide, also induced Bcl-2 S-nitrosylation, suggesting that this is a general phenomenon that regulates Bcl-2 stability and function under various stress conditions. These findings indicate a novel function of NO and its regulation of Bcl-2, which provides a key mechanism for the control of apoptotic cell death and cancer development.
Keywords
Proteins; Chromium-compounds; Oxides; Cell-damage; Cancer; Biological-effects; Biological-factors
Contact
Deptartment of Pharmaceutical Sciences, West Virginia University, P.O. Box 9530, Morgantown, WV 26506
CODEN
JBCHA3
CAS No.
10102-43-9; 7440-47-3
Publication Date
20061110
Document Type
Journal Article
Email Address
yrojanasakul@hsc.wvu.edu
Fiscal Year
2007
NTIS Accession No.
NTIS Price
Issue of Publication
45
ISSN
0021-9258
NIOSH Division
HELD
Priority Area
Research Tools and Approaches: Cancer Research Methods
Source Name
Journal of Biological Chemistry
State
WV
TOP