A molecular assembly phase transition and kinetic proofreading modulate Ras activation by SOS
A molecular assembly phase transition and kinetic proofreading modulate Ras activation by SOS
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DOI：
10.1126/science.aau5721
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发表时间：
2019-03-08
期刊：
影响因子：
56.9
通讯作者：
Groves, Jay T.
中科院分区：
文献类型：
--
作者：
Huang, William Y. C.;Alvarez, Steven;Groves, Jay T.
鸟苷酸交换因子（GEF）七子（SOS）是一种关键的Ras激活剂，它在细胞质中被自动抑制，并在膜募集时激活。自抑制释放涉及蛋白质在膜上的结构重排，因此在初始募集和活化之间引入延迟。在这项研究中，我们设计了一个单分子测定，以解决初始受体介导的膜招聘和启动GEF活动的单个SOS分子的Ras功能化的支持膜的微阵列之间的时间。测量的SOS激活时间分布的上升和下降形状和激活的长平均时间尺度（类似于50秒）建立了Ras受体介导的激活中的动力学校正的基础。我们进一步证明，这种动力学校正是由LAT（T细胞活化的连接体）-Grb 2-SOS磷酸酪氨酸驱动的膜相变调节的。
The guanine nucleotide exchange factor (GEF) Son of Sevenless (SOS) is a key Ras activator that is autoinhibited in the cytosol and activates upon membrane recruitment. Autoinhibition release involves structural rearrangements of the protein at the membrane and thus introduces a delay between initial recruitment and activation. In this study, we designed a single-molecule assay to resolve the time between initial receptor-mediated membrane recruitment and the initiation of GEF activity of individual SOS molecules on microarrays of Ras-functionalized supported membranes. The rise-and-fall shape of the measured SOS activation time distribution and the long mean time scale to activation (similar to 50 seconds) establish a basis for kinetic proofreading in the receptor-mediated activation of Ras. We further demonstrate that this kinetic proofreading is modulated by the LAT (linker for activation of T cells)-Grb2-SOS phosphotyrosine-driven phase transition at the membrane.