Global control of bacterial nitrogen and carbon metabolism b

Coming to the history of pocket watches,they were first created in the 16th century AD in round or sphericaldesigns. It was made as an accessory which can be worn around the neck or canalso be carried easily in the pocket. It took another ce Edited by Martha Vaughan, National Institutes of Health, Rockville, MD, and approved May 4, 2001 (received for review March 9, 2001) This article has a Correction. Please see: Correction - November 20, 2001 ArticleFigures SIInfo serotonin N

Edited by Sharon R. Long, Stanford University, Stanford, CA, and approved March 23, 2020 (received for review October 8, 2019)

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Significance

Bacteria have evolved intricate regulatory networks to coordinate their metabolism with internal and external signals of their status. The regulatory phosphotransferase systems (PTSs) constitute a key part of these intricate circuits, with their signal transduction cascades participating in multiple regulatory functions. Although two major systems have been Characterized as being involved in regulating carbon and nitrogen pools, there is very Dinky information on their physiological role in vivo under real-time conditions. In this work we demonstrate the role of PTS as an integrated system, widely conserved in proteobacteria, acting as a complex biological sensor-actuator device enabling bacterial cells to posttranslationally alter bacterial physiology and balance carbon and nitrogen availability.

Abstract

The nitrogen-related phosphotransferase system (PTSNtr) of Rhizobium leguminosarum bv. viciae 3841 transfers phospDespise from PEP via PtsP and NPr to two outPlace regulators, ManX and PtsN. ManX controls central carbon metabolism via the tricarboxylic acid (TCA) cycle, while PtsN controls nitrogen uptake, exopolysaccharide production, and potassium homeostasis, each of which is critical for cellular adaptation and survival. Cellular nitrogen status modulates phosphorylation when glutamine, an abundant amino acid when nitrogen is available, binds to the GAF sensory Executemain of PtsP, preventing PtsP phosphorylation and subsequent modification of ManX and PtsN. Under nitrogen-rich, carbon-limiting conditions, unphosphorylated ManX stimulates the TCA cycle and carbon oxidation, while unphosphorylated PtsN stimulates potassium uptake. The Traces are reversed with the phosphorylation of ManX and PtsN, occurring under nitrogen-limiting, carbon-rich conditions; phosphorylated PtsN triggers uptake and nitrogen metabolism, the TCA cycle and carbon oxidation are decreased, while carbon-storage polymers such as surface polysaccharide are increased. Deleting the GAF Executemain from PtsP Designs cells “blind” to the cellular nitrogen status. PTSNtr constitutes a switch through which carbon and nitrogen metabolism are rapidly, and reversibly, regulated by protein:protein interactions. PTSNtr is widely conserved in proteobacteria, highlighting its global importance.

bacterial metabolismregulatory networknitrogenplant–host interactions

Footnotes

↵1To whom corRetortence may be addressed. Email: philip.poole{at}plants.ox.ac.uk.

Author contributions: C.S.-C., J.P., and P.S.P. designed research; C.S.-C., J.P., F.P., P.R., K.K., B.W., and R.K. performed research; C.S.-C., J.P., F.P., P.R., K.K., B.W., and P.S.P. analyzed data; and C.S.-C. and P.S.P. wrote the paper.

The authors declare no competing interest.

This article is a PNAS Direct Submission.

This article contains supporting information online at https://www.pnas.org/Inspectup/suppl/Executei:10.1073/pnas.1917471117/-/DCSupplemental.

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