Research Institute for Health Sciences, Chiang Mai University, POBOX 80 CMU, Chiang Mai, Thailand 50200.
J Insect Sci. 2012;12:107. doi: 10.1673/031.012.10701.
Glutathione transferases (GSTs) are a family of multifunctional enzymes involved in xenobiotic biotransformation, drug metabolism, and protection against oxidative damage. The p38b mitogen-activated protein kinase is involved in cellular stress response. This study screened interactions between Drosophila melanogaster Meigen (Diptera: Drosophilidae) Delta class glutathione transferases (DmGSTs) and the D. melanogaster p38b MAPK. Therefore, 12 DmGSTs and p38b kinase were obtained as recombinant proteins. The study showed that DmGSTD8 and DmGSTD11b significantly increased p38b activity toward ATF2 and jun, which are transcription factor substrates. DmGSTD3 and DmGSTD5 moderately increased p38b activity for jun. In addition, GST activity in the presence of p38b was also measured. It was found that p38b affected substrate specificity toward CDNB (1-chloro-2,4-dinitrobenzene) and DCNB (1,2-dichloro-4-nitrobenzene) of several GST isoforms, i.e., DmGSTD2, DmGSTD5, DmGSTD8, and DmGSTD11b. The interaction of a GST and p38b can affect the substrate specificity of either enzyme, which suggests induced conformational changes affecting catalysis. Similar interactions do not occur for all the Delta enzymes and p38b, which suggests that these interactions could be specific.
谷胱甘肽转移酶（GSTs）是一组多功能酶，参与外来生物的生物转化、药物代谢和抗氧化损伤的保护。p38b 丝裂原活化蛋白激酶参与细胞应激反应。本研究筛选了黑腹果蝇 Delta 类谷胱甘肽转移酶（DmGSTs）与黑腹果蝇 p38b MAPK 之间的相互作用。因此，获得了 12 种 DmGST 和 p38b 激酶的重组蛋白。研究表明，DmGSTD8 和 DmGSTD11b 显著增加了 p38b 对 ATF2 和 jun 的活性，这是转录因子的底物。DmGSTD3 和 DmGSTD5 适度增加了 p38b 对 jun 的活性。此外，还测量了存在 p38b 时的 GST 活性。结果发现，p38b 影响了几种 GST 同工酶（DmGSTD2、DmGSTD5、DmGSTD8 和 DmGSTD11b）对 CDNB（1-氯-2,4-二硝基苯）和 DCNB（1,2-二氯-4-硝基苯）的底物特异性。GST 和 p38b 的相互作用可以影响任一酶的底物特异性，这表明诱导的构象变化影响催化作用。并非所有的 Delta 酶和 p38b 都发生这种相互作用，这表明这些相互作用可能是特异性的。
