Intrinsically disordered linkers control tethered kinases via effective concentration
Intrinsically disordered linkers control tethered kinases via effective concentration
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DOI：
10.1073/pnas.2006382117
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发表时间：
2020-09-01
影响因子：
11.1
通讯作者：
Kjaergaard, Magnus
中科院分区：
文献类型：
--
作者：
Dyla, Mateusz;Kjaergaard, Magnus
激酶的特异性对信号通路的保真度至关重要，然而许多通路使用相同的激酶来实现截然不同的效果。特异性部分来自酶结构域，但也来自于激酶与其底物的物理连接。这种拴系可以通过蛋白相互作用区域或通过锚定和支架蛋白发生，并可以显著增加磷酸化的动力学。然而，我们不知道这种复合体内反应如何依赖于酶和底物之间的联系。在这里，我们表明，系留蛋白激酶的动力学遵循米氏-门腾式的有效浓度依赖关系。我们发现，磷酸化动力学随连接酶和底物的内在无序连接物的长度而变化，但底物之间的比例不同。稳态动力学只能部分预测束缚反应的速率，因为产物的释放可能掩盖了磷转移的速率。我们的结果表明，信号复合体结构的变化不仅提高了磷酸化反应的速度，还可能改变相对底物的使用。这为支架蛋白如何变构改变信号通路的输出提供了一种机制。
Kinase specificity is crucial to the fidelity of signaling pathways, yet many pathways use the same kinases to achieve widely different effects. Specificity arises in part from the enzymatic domain but also from the physical tethering of kinases to their substrates. Such tethering can occur via protein interaction domains in the kinase or via anchoring and scaffolding proteins and can drastically increase the kinetics of phosphorylation. However, we do not know how such intracomplex reactions depend on the link between enzyme and substrate. Here we show that the kinetics of tethered kinases follow a Michaelis-Menten-like dependence on effective concentration. We find that phosphorylation kinetics scale with the length of the intrinsically disordered linkers that join the enzyme and substrate but that the scaling differs between substrates. Steady-state kinetics can only partially predict rates of tethered reactions as product release may obscure the rate of phosphotransfer. Our results suggest that changes in signaling complex architecture not only enhance the rates of phosphorylation reactions but may also alter the relative substrate usage. This suggests a mechanism for how scaffolding proteins can allosterically modify the output from a signaling pathway.