Asymmetric Modulation of Protein Order-Disorder Transitions by Phosphorylation and Partner Binding.
Asymmetric Modulation of Protein Order-Disorder Transitions by Phosphorylation and Partner Binding.
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DOI：
10.1002/anie.201507728
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发表时间：
2016-01-26
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影响因子：
--
通讯作者：
Deniz AA
中科院分区：
文献类型：
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作者：
Banerjee PR;Mitrea DM;Kriwacki RW;Deniz AA
塑料景观有利于功能形状的转变。单分子和整体实验揭示了条件性无序致癌蛋白的替代折叠组装途径。翻译后修饰和伴侣结合对各个步骤有不同的影响，并且可以相互抵消。可调节的机械路线突出了复杂的景观，可以有效地实现其多种细胞功能。对于许多本质上无序的蛋白质，多功能核仁蛋白核磷蛋白 (Npm-N) 的 N 端寡聚结构域中的有序-无序转换是其功能的核心，磷酸化和配偶体结合充当调节开关。然而，这种转变的机制及其受这些因素的调节仍然知之甚少。在这里，单分子和整体实验揭示了 Npm-N 具有替代折叠和组装步骤顺序的途径，可通过改变离子强度进行切换。磷酸化会产生通路特异性效应，并解耦折叠和组装步骤以促进紊乱。相反，与生理伙伴的结合将 Npm-N 锁定在有序五聚体中，并抵消磷酸化的影响。我们的研究结果揭示了 Npm-N 有序-无序转变中的机械可塑性，这使得磷酸化和伴侣结合在调节其折叠景观中发生复杂的相互作用。
Plastic landscape facilitates functional shape-shifting. Alternative folding-assembly pathways of a conditionally disordered oncogenic protein were revealed by single-molecule and ensemble experiments. Posttranslational modification and partner binding have differential effects on individual steps, and can counteract each other. Tunable mechanistic routes highlight a complex landscape that could efficiently enable its multiple cellular functions. As for many intrinsically disordered proteins, order-disorder transitions in the N-terminal oligomerization domain of the multi-functional nucleolar protein, nucleophosmin (Npm-N) are central to its function, with phosphorylation and partner-binding acting as regulatory switches. However, the mechanism of this transition and its regulation by these factors remain poorly understood. Here, single-molecule and ensemble experiments revealed pathways with alternative sequence of folding and assembly steps for Npm-N, switchable by altering ionic strength. Phosphorylation resulted in pathway-specific effects, and decoupled folding and assembly steps to facilitate disorder. Conversely, binding to a physiological partner locked Npm-N in ordered pentamers, and counteracted the effects of phosphorylation. Our findings revealed mechanistic plasticity in the Npm-N order-disorder transition, which enabled a complex interplay of phosphorylation and partner binding in modulating its folding landscape.