Activator protein oxidative stress

If cellular redox state, determined by the glutathione status of the heart, plays a role in the modulation of ion transporter activity in cardiac tissue, it is important to identify possible mechanisms by which these effects are mediated. Protein S-,thiolation is a process that was originally used to describe the formation of adducts of proteins with low molecular thiols such as glutathione (Miller etal., 1990). In view of the significant alterations of cardiac glutathione status (GSH and GSSG) and ion-transporter activity during oxidant stress, the process of S-thiolation may be responsible for modifications of protein structure and function. 

Recent developments in cellular biology have demonstrated the important role of mitogenic signal transduction in controlling the tumor proliferation. The induction of ornithine decarboxylase (ODC), PKC, protein kinase activities, and oxidative stress by the phorbol ester, TPA, is believed to be closely related to the tumor promotion activity of this compound. Topical application of green tea polyphenols to mouse skin was found to inhibit TPA-caused induction of ODC activity in a dose-dependent manner. Our studies demonstrated that EGCG and TF-3 inhibited TPA-induced transformation, PKC activation, and AP-1 binding activities in mouse fibroblast cells. ... 

An excellent example of the regulatory function of Fe-S clusters, can be found in SoxR, which is discussed by Demple in Chapter 11. This protein is a [2Fe-2S] cluster-containing transcriptional regulator, which is activated by oxidative stress through the oxidation of its iron-sulfur centers, thus acting thus as a regulatory redox switch. 

Mitogen-activated protein kinases (MAPKs) mediate apoptosis and cell growth, and jim N-terminal kinase (JNK) in particular is activated by oxidative stress. Yang et al. (2008) suggested that JNKs/SAPKs and p38 MAPK are classic oxidative stress-activated protein kinases, and Kim et al. (2004) observed that treatment with selenite increased intracellular reactive oxygen species (ROS) levels and JNKl phosphorylation in Chang liver cells. 

Kruman 11, Nath A, Mattson MP (1998) HlV-1 protein Tat induces apoptosis of hippocampal neurons by a mechanism involving caspase activation, calcium overload, and oxidative stress. Exp Neurol 154(2) 276-288... 

While many biological molecules may be targets for oxidant stress and free radicals, it is clear that the cell membrane and its associated proteins may be particularly vulnerable. The ability of the cell to control its intracellular ionic environment as well as its ability to maintain a polarized membrane potential and electrical excitability depends on the activity of ion-translocating proteins such as channels, pumps and exchangers. Either direct or indirect disturbances of the activity of these ion translocators must ultimately underlie reperfiision and oxidant stress-induced arrhythmias in the heart. A number of studies have therefore investigated the effects of free radicals and oxidant stress on cellular electrophysiology and the activity of key membrane-bound ion translocating proteins. 

It has been demonstrated in other cell types that lutein can inhibit expression of MMPs and/ or activity (Philips et al., 2007). For example, in dermal fibroblasts lutein inhibits expression of MMP-1 and decreases levels of MMP-2 protein (Philips et al., 2007). In melanoma cells, lutein inhibits MMP-1 expression while stimulating TIMP-2 (Philips et al., 2007). Moreover it has been shown that lutein inhibits elastin expression in fibroblasts subjected to oxidative stress by exposure to ultraviolet light (Philips et al., 2007). These results clearly indicate that lutein can play an important role in remodeling of the extracellular matrix. 

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