Cryo-electron microscopy structure and analysis of the P-Rex1-Gβγ signaling scaffold
Cryo-electron microscopy structure and analysis of the P-Rex1-Gβγ signaling scaffold
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DOI：
10.1126/sciadv.aax8855
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发表时间：
2019-10-01
期刊：
影响因子：
13.6
通讯作者：
Cianfrocco, Michael A.
中科院分区：
文献类型：
--
作者：
Cash, Jennifer N.;Urata, Sarah;Cianfrocco, Michael A.
PIP 3依赖性Rac交换器1（P-Rex 1）在G蛋白偶联受体下游被激活，以促进中性粒细胞迁移和转移。超过一半的酶的结构及其调节G蛋白结合位点是未知的。我们的P-Rex 1-G β γ复合物的3.2埃冷冻-EM结构显示，P-Rex 1的羧基末端一半采用了与军团菌磷酸肌醇磷酸酶最相似的复杂折叠。虽然催化惰性，该结构域与DEP结构域和两个PDZ结构域聚结，形成广泛的对接站点Gk。氢-氘交换质谱表明，G β γ，结合诱导P-Rex 1的变构变化，但功能测定表明，膜定位也需要完全激活。因此，多结构域组装是通过G β γ调节P-Rex 1的关键，并且形成膜定位支架，该支架被优化用于募集其他信号蛋白如PKA和PTEN。
PIP3-dependent Rac exchanger 1 (P-Rex1) is activated downstream of G protein-coupled receptors to promote neutrophil migration and metastasis. The structure of more than half of the enzyme and its regulatory G protein binding site are unknown. Our 3.2 angstrom cryo-EM structure of the P-Rex1-G beta gamma, complex reveals that the carboxyl-terminal half of P-Rex1 adopts a complex fold most similar to those of Legionella phosphoinositide phosphatases. Although catalytically inert, the domain coalesces with a DEP domain and two PDZ domains to form an extensive docking site for Gk. Hydrogen-deuterium exchange mass spectrometry suggests that G beta gamma, binding induces allosteric changes in P-Rex1, but functional assays indicate that membrane localization is also required for full activation. Thus, a multidomain assembly is key to the regulation of P-Rex1 by G beta gamma, and the formation of a membrane-localized scaffold optimized for recruitment of other signaling proteins such as PKA and PTEN.