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起重要作用。这类酶的活性受到细胞质和细胞核抑制剂的密切调节。这些抑制剂与靶蛋白酶的相互作用部分地由强疏水相互作用介导。乙醇暴露对半胱氨酸蛋白酶活性的影响已经在细胞培养中利用PC12细胞系进行了研究。这些蛋白酶的活性似乎受到酒精暴露的强烈影响。我们以前已经确定，暴露的PC12细胞的乙醇96小时的结果在钙刺激的蛋白酶活性降低。我们正在努力确定这种酒精诱导的钙激活蛋白酶活性抑制的机制。我们有初步的证据表明，钙蛋白酶可能会重新分布在PC12细胞作为乙醇暴露的结果，这种重新分布改变了洗涤剂的能力，从细胞中提取钙蛋白酶蛋白。我们还发现，虽然钙蛋白酶抑制剂（钙蛋白酶的内源性抑制剂）的水平在乙醇暴露后没有显著改变，但基于翻译后修饰，其抑制钙蛋白酶的能力可能存在差异。其中一种可能性是蛋白质中丝氨酸残基的磷酸化在乙醇暴露后发生改变，我们正在确定这些改变在乙醇暴露后调节钙蛋白酶抑制蛋白抑制活性的程度和意义。- 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