Phosphate signaling through alternate conformations of the PstSCAB phosphate transporter
Abstract Background 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...
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| Format: | Article |
| Language: | English |
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BMC
2018-01-01
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| Series: | BMC Microbiology |
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| Online Access: | http://link.springer.com/article/10.1186/s12866-017-1126-z |
| _version_ | 1811263837938122752 |
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| author | Ramesh K. Vuppada Colby R. Hansen Kirsta A. P. Strickland Keilen M. Kelly William R. McCleary |
| author_facet | Ramesh K. Vuppada Colby R. Hansen Kirsta A. P. Strickland Keilen M. Kelly William R. McCleary |
| author_sort | Ramesh K. Vuppada |
| collection | DOAJ |
| description | Abstract Background 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. Results 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. Conclusions 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. |
| first_indexed | 2024-04-12T19:52:16Z |
| format | Article |
| id | doaj.art-a34756a8b5db450a97a22b3322e4d1bf |
| institution | Directory Open Access Journal |
| issn | 1471-2180 |
| language | English |
| last_indexed | 2024-04-12T19:52:16Z |
| publishDate | 2018-01-01 |
| publisher | BMC |
| record_format | Article |
| series | BMC Microbiology |
| spelling | doaj.art-a34756a8b5db450a97a22b3322e4d1bf2022-12-22T03:18:46ZengBMCBMC Microbiology1471-21802018-01-011811910.1186/s12866-017-1126-zPhosphate signaling through alternate conformations of the PstSCAB phosphate transporterRamesh K. Vuppada0Colby R. Hansen1Kirsta A. P. Strickland2Keilen M. Kelly3William R. McCleary4Department of Microbiology and Molecular Biology, Brigham Young UniversityDepartment of Microbiology and Molecular Biology, Brigham Young UniversityDepartment of Microbiology and Molecular Biology, Brigham Young UniversityDepartment of Microbiology and Molecular Biology, Brigham Young UniversityDepartment of Microbiology and Molecular Biology, Brigham Young UniversityAbstract Background 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. Results 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. Conclusions 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.http://link.springer.com/article/10.1186/s12866-017-1126-zPhosphate homeostasisTwo-component signal transductionHistidine kinaseABC transporter |
| spellingShingle | Ramesh K. Vuppada Colby R. Hansen Kirsta A. P. Strickland Keilen M. Kelly William R. McCleary Phosphate signaling through alternate conformations of the PstSCAB phosphate transporter BMC Microbiology Phosphate homeostasis Two-component signal transduction Histidine kinase ABC transporter |
| title | Phosphate signaling through alternate conformations of the PstSCAB phosphate transporter |
| title_full | Phosphate signaling through alternate conformations of the PstSCAB phosphate transporter |
| title_fullStr | Phosphate signaling through alternate conformations of the PstSCAB phosphate transporter |
| title_full_unstemmed | Phosphate signaling through alternate conformations of the PstSCAB phosphate transporter |
| title_short | Phosphate signaling through alternate conformations of the PstSCAB phosphate transporter |
| title_sort | phosphate signaling through alternate conformations of the pstscab phosphate transporter |
| topic | Phosphate homeostasis Two-component signal transduction Histidine kinase ABC transporter |
| url | http://link.springer.com/article/10.1186/s12866-017-1126-z |
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