Salomon Michael S, Malapati S Harshini, O' Dwyer Jerry, Silva Carolina Lopez, Williams Cheyenne C, Barbeau Michelle C, Yip Delbert, Punzalan Paige, Nagle Veronica L, Hinton Shantá D, Roggero Vincent R, Allison Lizabeth A
Department of Biology, William & Mary, 540 Landrum Drive, ISC 3035, Williamsburg, VA, 23185, USA.
Nucl Receptor Res. 2020;2020.
The thyroid hormone receptor (TR) is essential for the proper regulation of metabolism and development, as it regulates gene expression in response to thyroid hormone. Nuclear localization signals (NLSs) and nuclear export signals (NESs) allow for TR transport into and out of the nucleus, respectively. Previous research suggests that nuclear import, nuclear retention, and nuclear export of TR are associated with modulation of gene expression, the alteration of which can contribute to various diseases. Here, we examined the impact of cancer-associated mutations on TR localization patterns as a way of analyzing key structural components of TR and to further explore the correlation between TR trafficking, misfolding, and disease. Through mammalian cell transfection of expression plasmids for green fluorescent protein (GFP) and mCherry-tagged TRα1 and quantitative fluorescence microscopy, we examined particular groups of TRα1 mutations that were observed in patients with hepatocellular carcinoma, renal cell carcinoma, and thyroid cancer, and are associated with NLSs and NESs of TRα1. We also investigated structural alterations of the mutants by modeling. Our results show striking shifts towards a more cytoplasmic localization for many of the mutants and an increased tendency to form cytosolic and nuclear aggregates.
甲状腺激素受体（TR）对于新陈代谢和发育的正常调节至关重要，因为它能响应甲状腺激素调节基因表达。核定位信号（NLSs）和核输出信号（NESs）分别使TR能够进入和离开细胞核。先前的研究表明，TR的核输入、核滞留和核输出与基因表达的调节有关，其改变可能导致各种疾病。在此，我们研究了癌症相关突变对TR定位模式的影响，以此分析TR的关键结构成分，并进一步探索TR转运、错误折叠与疾病之间的相关性。通过对绿色荧光蛋白（GFP）和mCherry标记的TRα1表达质粒进行哺乳动物细胞转染以及定量荧光显微镜观察，我们研究了在肝细胞癌、肾细胞癌和甲状腺癌患者中观察到的、与TRα1的NLSs和NESs相关的特定TRα1突变组。我们还通过建模研究了突变体的结构改变。我们的结果表明，许多突变体的定位明显向细胞质转移，并且形成胞质和核聚集体的倾向增加。
