Lee Hye Kyung, Chen Jichun, Philips Rachael L, Lee Sung-Gwon, Feng Xingmin, Wu Zhijie, Liu Chengyu, Schultz Aaron B, Dalzell Molly, Meggendorfer Manja, Haferlach Claudia, Birnbaum Foster, Sexton Joel A, Keating Amy E, O'Shea John J, Young Neal S, Villarino Alejandro V, Furth Priscilla A, Hennighausen Lothar
Laboratory of Genetics and Physiology, National Institute of Diabetes and Digestive and Kidney Diseases, US National Institutes of Health, Bethesda, MD, USA
Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
Life Sci Alliance. 2025 Apr 14;8(7). doi: 10.26508/lsa.202503222. Print 2025 Jul.
STAT5B is a vital transcription factor for lymphocytes. Here, the function of two STAT5B mutations from human T-cell leukemias: one substituting tyrosine 665 with phenylalanine (STAT5B) and the other with histidine (STAT5B), was interrogated. In silico modeling predicted divergent energetic effects on homodimerization with a range of pathogenicity. In primary T cells in vitro, STAT5B showed gain-of-function, whereas STAT5B demonstrated loss-of-function. Introducing the mutation into the mouse genome illustrated that the gain-of-function mutation resulted in accumulation of CD8 effector and memory and CD4 regulatory T cells, altering CD8/CD4 ratios. In contrast, STAT5B "knock-in" mice showed diminished CD8 effector and memory and CD4 regulatory T cells. In contrast to WT STAT5B, the STAT5B variant displayed greater STAT5 phosphorylation, DNA binding, and transcriptional activity after cytokine activation, whereas the STAT5B variant resembled a null. The work exemplifies how joining in silico and in vivo studies of single nucleotides deepens our understanding of disease-associated variants, revealing structural determinants of altered function, defining mechanistic roles, and, specifically here, identifying a gain-of-function variant that does not directly induce hematopoietic malignancy.
信号转导和转录激活因子5B（STAT5B）是淋巴细胞的一种重要转录因子。在此，对来自人类T细胞白血病的两种STAT5B突变的功能进行了研究：一种是将酪氨酸665替换为苯丙氨酸（STAT5B），另一种是替换为组氨酸（STAT5B）。计算机模拟预测了对同源二聚化具有一系列致病性的不同能量效应。在体外原代T细胞中，STAT5B表现出功能获得，而STAT5B表现出功能丧失。将该突变引入小鼠基因组表明，功能获得性突变导致CD8效应细胞和记忆细胞以及CD4调节性T细胞积累，改变了CD8/CD4比率。相比之下，STAT5B“敲入”小鼠的CD8效应细胞、记忆细胞和CD4调节性T细胞减少。与野生型STAT5B相比，STAT5B变体在细胞因子激活后表现出更高的STAT5磷酸化、DNA结合和转录活性，而STAT5B变体则类似无效突变。这项工作例证了将单核苷酸的计算机模拟和体内研究相结合如何加深我们对疾病相关变体的理解，揭示功能改变的结构决定因素，定义机制作用，特别是在此处，鉴定出一种不直接诱导造血系统恶性肿瘤的功能获得性变体。
