Heling Laurens W H J, Sheikhhassani Vahid, Ng Julian, van Vliet Morris, Jiménez-Panizo Alba, Alegre-Martí Andrea, Woodard Jaie, van Roon-Mom Willeke, McEwan Iain J, Estébanez-Perpiñá Eva, Mashaghi Alireza
Medical Systems Biophysics and Bioengineering, Division of Systems Pharmacology and Pharmacy, Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands.
Laboratory for Interdisciplinary Medical Innovations, Centre for Interdisciplinary Genome Research, Leiden University, Leiden, The Netherlands.
Protein Sci. 2025 Jun;34(6):e70154. doi: 10.1002/pro.70154.
Spinal bulbar muscular atrophy (SBMA) is caused by a polyglutamine expansion (pQe) in the N-terminal transactivation domain of the human androgen receptor (AR-NTD), resulting in a combination of toxic gain- and loss-of-function mechanisms. The structural basis of these processes has not been resolved due to the disordered nature of the NTD, which hinders experimental analyses of its detailed conformations. Here, using extensive computational modeling, we show that AR-NTD forms dynamic compact regions, which upon pQe re-organize dynamically, mediated partly by direct pQ interaction with the Androgen N-Terminal Signature (ANTS) motif. The altered dynamics of the NTD result in a perturbation of interdomain interactions, with potential implications for the binding of the receptor protein to its response element. Oligomeric aggregation of the dynamic misfolded NTD exposes pQe, but blocks tau-5 and the FQNLF motif, which could lead to aberrant receptor transcriptional activity. These observations suggest a structural mechanism for AR dysfunction in SBMA.
脊髓延髓性肌萎缩症(SBMA)是由人类雄激素受体N端反式激活结构域(AR-NTD)中的多聚谷氨酰胺扩增(pQe)引起的,导致毒性功能获得和功能丧失机制的结合。由于NTD的无序性质,这些过程的结构基础尚未得到解决,这阻碍了对其详细构象的实验分析。在这里,我们使用广泛的计算模型表明,AR-NTD形成动态紧密区域,在pQe作用下,这些区域会动态重新组织,部分由pQ与雄激素N端特征(ANTS)基序的直接相互作用介导。NTD动态变化导致结构域间相互作用受到干扰,这可能对受体蛋白与其反应元件的结合产生影响。动态错误折叠的NTD的寡聚聚集暴露了pQe,但阻断了tau-5和FQNLF基序,这可能导致受体转录活性异常。这些观察结果提示了SBMA中AR功能障碍的一种结构机制。