Phosphate signaling through alternate conformations of the PstSCAB phosphate transporter.
Phosphate signaling through alternate conformations of the PstSCAB phosphate transporter.
复制标题
PSTSCAB磷酸转运蛋白的替代构象通过磷酸盐信号传导。
DOI：
10.1186/s12866-017-1126-z
复制
发表时间：
2018-01-19
期刊：
影响因子：
4.2
通讯作者：
McCleary WR
中科院分区：
文献类型：
--
作者：
Vuppada RK;Hansen CR;Strickland KAP;Kelly KM;McCleary WR
磷酸盐是生命所必需的化合物。大肠杆菌采用一种信号转导途径，控制高亲和力获取磷酸盐和利用替代磷源所需基因的表达。这些基因只有在环境磷酸盐有限的情况下才会表达。该信号通路的七个基因编码由两个组分组成的调节蛋白Phob和Phor，以及高亲和力的磷酸盐转运蛋白PstSCAB和一种名为Phou的辅助蛋白。由于感受器激酶phor没有周质感受域，这些细胞感知环境磷酸盐的机制尚不清楚。本文探讨了PstSCAB转运蛋白的交替构象是作为正常磷运输循环的一部分而形成的信号信号磷充足或磷限制的假说。我们测试了PstB的两个变种，预计它们会将蛋白质锁定在两种构象中的任何一种，以进行信号输出。我们观察到pstBQ160K突变，预测存在于向内的开放构象中，表明磷充足，而pstBE179Q突变，预测存在于向外的封闭构象，表明磷饥饿。两个突变体都没有表现出磷酸盐运输。这些结果支持PstSCAB转运蛋白的交替构象是由Phor和Phou感知的假说。因此，这种感觉机制控制着Phor的交替的自激酶和磷酸酶的活性，最终控制着反应调节器Phob的信号状态。
Phosphate is an essential compound for life. Escherichia coli employs a signal transduction pathway that controls the expression of genes that are required for the high-affinity acquisition of phosphate and the utilization of alternate sources of phosphorous. These genes are only expressed when environmental phosphate is limiting. The seven genes for this signaling pathway encode the two-component regulatory proteins PhoB and PhoR, as well as the high-affinity phosphate transporter PstSCAB and an auxiliary protein called PhoU. As the sensor kinase PhoR has no periplasmic sensory domain, the mechanism by which these cells sense environmental phosphate is not known. This paper explores the hypothesis that it is the alternating conformations of the PstSCAB transporter which are formed as part of the normal phosphate transport cycle that signal phosphate sufficiency or phosphate limitation. We tested two variants of PstB that are predicted to lock the protein in either of two conformations for their signaling output. We observed that the pstBQ160K mutant, predicted to reside in an inward-facing, open conformation signaled phosphate sufficiency whereas the pstBE179Q mutant, predicted to reside in an outward-facing, closed conformation signaled phosphate starvation. Neither mutant showed phosphate transport. These results support the hypothesis that the alternating conformations of the PstSCAB transporter are sensed by PhoR and PhoU. This sensory mechanism thus controls the alternate autokinase and phospho-PhoB phosphatase activities of PhoR, which ultimately control the signaling state of the response regulator PhoB.
登录
查看更多内容
影响因子：
64.8
作者：
Oldham, Michael L.;Khare, Dheeraj;Chen, Jue
通讯作者：
Chen, Jue
影响因子：
5.6
作者：
MAKINO, K;SHINAGAWA, H;NAKATA, A
通讯作者：
NAKATA, A
影响因子：
2.9
作者：
Gardner SG;Miller JB;Dean T;Robinson T;Erickson M;Ridge PG;McCleary WR
通讯作者：
McCleary WR
DOI：
10.1073/pnas.120163297
发表时间：
2000-06-06
影响因子：
11.1
作者：
Datsenko, KA;Wanner, BL
通讯作者：
Wanner, BL
影响因子：
5.6
作者：
Makino, K;Amemura, M;Suzuki, M
通讯作者：
Suzuki, M