Abstract：
The ubiquitin-proteasome pathway (UPP) is a major route for protein degradation and a key regulatory mechanism in mammalian cells. UPP inhibitors, including TAK-243, a first-in-class inhibitor of the E1 ubiquitin-activating enzyme, are currently being used and tested for treatment of a range of diseases, particularly cancer. Here, we reveal that TAK-243 has major effects on Ca2+ handling in a range of cultured mammalian cells (αT3, HeLa and SH-SY5Y). Effects were seen on agonist-induced Ca2+ mobilization, basal cytosolic Ca2+ levels, Ca2+ leak from the endoplasmic reticulum (ER), store-operated Ca2+ entry and mitochondrial Ca2+ uptake. These effects correlated with induction of ER stress, as measured by PERK activation / eIF2α phosphorylation, and most seemed to be underpinned by enhanced Ca2+ leak from the ER. Overall, these data indicate that TAK-243 reprograms the Ca2+-handling properties of mammalian cells and that these effects should be considered when UPP inhibitors are employed as therapeutic agents.
摘要：
泛素-蛋白酶体途径（UPP）是哺乳动物细胞中蛋白质降解的主要途径和关键调节机制。UPP抑制剂，包括TAK-243，E1泛素激活酶的一类抑制剂，目前正在使用和测试一系列疾病的治疗，尤其是癌症。这里,我们发现TAK-243对一系列培养的哺乳动物细胞（αT3，HeLa和SH-SY5Y）中的Ca2处理具有主要影响。观察到对激动剂诱导的Ca2+动员的影响，基础胞质Ca2+水平，Ca2+从内质网(ER)渗漏,储存操作的Ca2+进入和线粒体Ca2+摄取。这些效应与内质网应激的诱导相关，并且大多数似乎是由ER的Ca2泄漏增强所支撑的。总的来说,这些数据表明TAK-243重新编程哺乳动物细胞的Ca2+处理特性,当UPP抑制剂用作治疗剂时,应考虑这些作用.
