Broniowska Katarzyna A, Zhang Yanhong, Hogg Neil
Department of Biophysics and Free Radical Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
J Biol Chem. 2006 Nov 10;281(45):33835-41. doi: 10.1074/jbc.M603248200. Epub 2006 Aug 7.
S-nitrosothiols have been implicated as intermediary transducers of nitric oxide bioactivity; however, the mechanisms by which these compounds affect cellular functions have not been fully established. In this study, we have examined the effect of S-nitrosothiol transport on intracellular thiol status and upon the activity of a target protein (caspase-3), in bovine aortic endothelial cells. We have previously demonstrated that the specific transport of amino acid-based S-nitrosothiols (S-nitroso-L-cysteine and S-nitrosohomocysteine) occurs via amino acid transport system L to generate high levels of intracellular protein S-nitrosothiols (Zhang, Y., and Hogg, N. (2004) Proc. Natl. Acad. Sci. U. S. A. 101, 7891-7896). In this study, we demonstrate that the transport of S-nitrosothiols is essential for these compounds to affect intracellular thiol levels and to modify intracellular protein activity. Importantly, the ability of these compounds to affect intracellular processes occurs independently of nitric oxide formation. These findings suggest that the major action of these compounds is not to liberate nitric oxide in the extracellular space but to be specifically transported into cells where they are able to modify cellular functions through nitric oxide-independent mechanisms.
S-亚硝基硫醇被认为是一氧化氮生物活性的中间转导分子；然而，这些化合物影响细胞功能的机制尚未完全明确。在本研究中，我们检测了S-亚硝基硫醇转运对牛主动脉内皮细胞内硫醇状态以及靶蛋白（半胱天冬酶-3）活性的影响。我们之前已证明基于氨基酸的S-亚硝基硫醇（S-亚硝基-L-半胱氨酸和S-亚硝基高半胱氨酸）的特异性转运是通过氨基酸转运系统L进行的，从而产生高水平的细胞内蛋白S-亚硝基硫醇（张，Y.，和霍格，N.（2004年）美国国家科学院院刊101，7891 - 7896）。在本研究中，我们证明S-亚硝基硫醇的转运对于这些化合物影响细胞内硫醇水平和改变细胞内蛋白活性至关重要。重要的是，这些化合物影响细胞内过程的能力独立于一氧化氮的形成。这些发现表明，这些化合物的主要作用不是在细胞外空间释放一氧化氮，而是被特异性转运到细胞内，在那里它们能够通过不依赖一氧化氮的机制改变细胞功能。
