INTERACTION OF ETHYL ALCOHOL WITH CELLULAR CYSTEINE PROTEASES

某些类型的细胞半胱氨酸蛋白酶可能在调节G蛋白偶联受体的活性中发挥重要作用。这类酶的活性受到细胞质和核抑制物的密切调控。这些抑制物与目标酶的相互作用部分是由强烈的疏水相互作用所介导的。在PC12细胞系的细胞培养中，研究了酒精暴露对半胱氨酸蛋白酶活性的影响。这些蛋白酶的活性似乎受到酒精暴露的强烈影响。我们先前已经证实，PC12细胞在酒精中暴露96小时会导致钙刺激的蛋白酶活性下降。我们正致力于确定酒精诱导的钙激活蛋白酶活性抑制的机制。我们有初步证据表明，由于酒精暴露，钙蛋白可能在PC12细胞中重新分布，这种重新分布改变了洗涤剂从细胞中提取钙蛋白的能力。我们还发现，虽然在乙醇暴露后，钙蛋白酶的内源性抑制物Calastatin的水平没有明显变化，但基于翻译后修饰，它抑制Calain的能力可能会有所不同。其中一种可能性是蛋白质中丝氨酸残基的磷酸化在酒精暴露后发生变化，我们正在确定这些变化在调节乙醇暴露后钙调蛋白抑制活性方面的程度和意义。-毒理学、神经科学、分子遗传学

Certain types of cellular cysteine proteases may play an important role in modulating the activity of G-protein coupled receptors. The activity of this class of enzymes is closely regulated by cytoplasmic and nuclear inhibitors. The interaction of these inhibitors with the target proteases is, in part, mediated by strong hydrophobic interactions. The effects of ethyl alcohol exposure on cysteine protease activity has been studied in cell culture utilizing a PC12 cell line. Activity of these proteases appears to be strongly affected by alcohol exposure. We have previously established that exposure of PC12 cells to ethyl alcohol for 96 hours results in a decrease in calcium-stimulated protease activity. We are working towards defining a mechanism for this alcohol-induced inhibition of calcium-activated protease activity. We have preliminary evidence that calpain may be redistributed in PC12 cells as a result of ethanol exposure, and that this redistribution alters the ability of detergents to extract calpain protein from cells. We have also found that while levels of calpastatin, the endogenous inhibitor of calpain, are not significantly altered after ethanol exposure, that there may be differences in its ability to inhibit calpain based on post-translational modifications. One of the possibilities is that the phosphorylation of serine residues in the protein is altered after ethanol exposure, and we are in the process of determining the extent and significance of these alterations in modulating the inhibitory activity of calpastatin after ethanol exposure. - toxicology, neurosciences, molecular genetics