Mechanism of β-actin mRNA Recognition by ZBP1.
Mechanism of β-actin mRNA Recognition by ZBP1.
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DOI：
10.1016/j.celrep.2016.12.091
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发表时间：
2017-01-31
期刊：
影响因子：
8.8
通讯作者：
Ramos A
中科院分区：
文献类型：
--
作者：
Nicastro G;Candel AM;Uhl M;Oregioni A;Hollingworth D;Backofen R;Martin SR;Ramos A
Zipcode binding protein 1 （ZBP1）是一种癌胎rna结合蛋白，通过KH3-KH4双结构域介导β-actin mRNA的转运和局部翻译，这对神经元发育至关重要。KH3-KH4与各自靶序列的高分辨率结构表明，KH4通过扩大的动态疏水槽识别非规范的GGA序列，而KH3与核心CA序列结合的特异性较低。两步结合反应的数据动力学模拟表明，整个反应是由第二个结合事件驱动的，并且单个相互作用的中等亲和力有利于RNA环化。此外，ZBP1的浓度，而不是靶RNA的浓度，调节相互作用，这解释了胚胎发育过程中ZBP1表达增强的功能意义。ZBP1的KH4结构域的动态凹槽允许识别富含g的RNA序列ZBP1的KH3和KH4结构域以相似的亲和力结合它们的靶RNA序列RNA环驱动ZBP1-β-actin相互作用，蛋白而不是RNA的浓度调节ZBP1-β-actin mRNA的结合，β-actin mRNA与RNA结合蛋白ZBP1的相互作用调节mRNA的转运和翻译，是神经元发育所必需的。Nicastro等人利用核磁共振和生物物理学表明，这种相互作用是由RNA环驱动的，并由蛋白质而不是RNA浓度调节。
Zipcode binding protein 1 (ZBP1) is an oncofetal RNA-binding protein that mediates the transport and local translation of β-actin mRNA by the KH3-KH4 di-domain, which is essential for neuronal development. The high-resolution structures of KH3-KH4 with their respective target sequences show that KH4 recognizes a non-canonical GGA sequence via an enlarged and dynamic hydrophobic groove, whereas KH3 binding to a core CA sequence occurs with low specificity. A data-informed kinetic simulation of the two-step binding reaction reveals that the overall reaction is driven by the second binding event and that the moderate affinities of the individual interactions favor RNA looping. Furthermore, the concentration of ZBP1, but not of the target RNA, modulates the interaction, which explains the functional significance of enhanced ZBP1 expression during embryonic development. The dynamic groove of ZBP1’s KH4 domain allows recognition of a G-rich RNA sequence ZBP1’s KH3 and KH4 domains bind their target RNA sequences with similar affinities RNA looping drives the ZBP1-β-actin interaction The protein, rather than the RNA, concentration regulates ZBP1-β-actin mRNA binding The interaction of β-actin mRNA with the RNA-binding protein ZBP1 regulates mRNA transport and translation and is necessary for neuronal development. Using NMR and biophysics, Nicastro et al. have shown that the interaction is driven by RNA looping and regulated by the protein, rather than the RNA, concentration.