来自大肠杆菌的 PhoU 蛋白与 PhoR、PstB 和金属相互作用，在膜上形成磷酸盐信号复合物。,Journal of Bacteriology

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来自大肠杆菌的 PhoU 蛋白与 PhoR、PstB 和金属相互作用，在膜上形成磷酸盐信号复合物。
Journal of Bacteriology ( IF 2.7 ) Pub Date : 2014-02-21 , DOI: 10.1128/jb.00029-14
Stewart G Gardner ₁ , Kristine D Johns , Rebecca Tanner , William R McCleary

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许多细菌的稳健生长取决于对磷酸盐 (Pi) 限制的适应性反应的适当调节。这种反应使细胞能够以高亲和力获取 Pi 并利用替代磷源。Pi信号转导的分子机制尚不完全清楚。PhoU 连同高亲和力、Pi 特异性 ATP 结合盒转运蛋白 PstSCAB 和双组分蛋白 PhoR 和 PhoB，对于大肠杆菌中的 Pi 信号传导是绝对必需的。关于 PhoU 的作用及其在调节中的功能知之甚少。我们已经使用细菌双杂交分析和确认性共流出实验证明 PhoU 通过其 PAS（Per-ARNT-Sim）结构域与 PhoR 相互作用，并且它还与转运蛋白的细胞质成分 PstB 相互作用。我们还表明 PhoU 的可溶形式是一种结合锰和镁的二聚体。通过定点诱变改变 PhoU 中高度保守的残基表明这些位点在结合金属中发挥作用。对这些 phoU 突变体的分析表明金属结合可能对 PhoU 膜相互作用很重要。综上所述，这些结果支持了 PhoU 参与形成细胞质膜信号复合物的假设，该信号复合物对环境 Pi 水平有反应。

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The PhoU protein from Escherichia coli interacts with PhoR, PstB, and metals to form a phosphate-signaling complex at the membrane.

Robust growth in many bacteria is dependent upon proper regulation of the adaptive response to phosphate (Pi) limitation. This response enables cells to acquire Pi with high affinity and utilize alternate phosphorous sources. The molecular mechanisms of Pi signal transduction are not completely understood. PhoU, along with the high-affinity, Pi-specific ATP-binding cassette transporter PstSCAB and the two-component proteins PhoR and PhoB, is absolutely required for Pi signaling in Escherichia coli. Little is known about the role of PhoU and its function in regulation. We have demonstrated using bacterial two-hybrid analysis and confirmatory coelution experiments that PhoU interacts with PhoR through its PAS (Per-ARNT-Sim) domain and that it also interacts with PstB, the cytoplasmic component of the transporter. We have also shown that the soluble form of PhoU is a dimer that binds manganese and magnesium. Alteration of highly conserved residues in PhoU by site-directed mutagenesis shows that these sites play a role in binding metals. Analysis of these phoU mutants suggests that metal binding may be important for PhoU membrane interactions. Taken together, these results support the hypothesis that PhoU is involved in the formation of a signaling complex at the cytoplasmic membrane that responds to environmental Pi levels.

更新日期：2019-11-01

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