Torque, but not FliL, regulates mechanosensitive flagellar motor-function

Abstract The stator-complex in the bacterial flagellar motor is responsible for surface-sensing. It remodels in response to perturbations in viscous loads, recruiting additional stator-units as the load increases. Here, we tested a hypothesis that the amount of torque generated by each stator-unit m...

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Main Authors:	Ravi Chawla, Katie M. Ford, Pushkar P. Lele
Format:	article
Language:	EN
Published:	Nature Portfolio 2017
Subjects:	Medicine R Science Q
Online Access:	https://doaj.org/article/d5b89c12869d4a4882eb491dd6fe1569
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spelling	oai:doaj.org-article:d5b89c12869d4a4882eb491dd6fe15692021-12-02T15:06:16ZTorque, but not FliL, regulates mechanosensitive flagellar motor-function10.1038/s41598-017-05521-82045-2322https://doaj.org/article/d5b89c12869d4a4882eb491dd6fe15692017-07-01T00:00:00Zhttps://doi.org/10.1038/s41598-017-05521-8https://doaj.org/toc/2045-2322Abstract The stator-complex in the bacterial flagellar motor is responsible for surface-sensing. It remodels in response to perturbations in viscous loads, recruiting additional stator-units as the load increases. Here, we tested a hypothesis that the amount of torque generated by each stator-unit modulates its association with the rotor. To do this, we measured stator-binding to the rotor in mutants in which motors reportedly develop lower torque compared to wildtype motors. First, we employed a strain lacking fliL. Contrary to earlier reports, measurements indicated that the torque generated by motors in the fliL strain was similar to that in the wildtype, at high loads. In these motors, stator-binding was unchanged. Next, experiments with a paralyzed strain indicated that the stator-binding was measurably weaker when motors were unable to generate torque. An analytical model was developed that incorporated an exponential dependence of the unit’s dissociation rate on the force delivered to the rotor. The model provided accurate fits to measurements of stator-rotor binding over a wide range of loads. Based on these results, we propose that the binding of each stator-unit is enhanced by the force it develops. Furthermore, FliL does not play a significant role in motor function in E. coli.Ravi ChawlaKatie M. FordPushkar P. LeleNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 7, Iss 1, Pp 1-9 (2017)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Ravi Chawla Katie M. Ford Pushkar P. Lele Torque, but not FliL, regulates mechanosensitive flagellar motor-function
description	Abstract The stator-complex in the bacterial flagellar motor is responsible for surface-sensing. It remodels in response to perturbations in viscous loads, recruiting additional stator-units as the load increases. Here, we tested a hypothesis that the amount of torque generated by each stator-unit modulates its association with the rotor. To do this, we measured stator-binding to the rotor in mutants in which motors reportedly develop lower torque compared to wildtype motors. First, we employed a strain lacking fliL. Contrary to earlier reports, measurements indicated that the torque generated by motors in the fliL strain was similar to that in the wildtype, at high loads. In these motors, stator-binding was unchanged. Next, experiments with a paralyzed strain indicated that the stator-binding was measurably weaker when motors were unable to generate torque. An analytical model was developed that incorporated an exponential dependence of the unit’s dissociation rate on the force delivered to the rotor. The model provided accurate fits to measurements of stator-rotor binding over a wide range of loads. Based on these results, we propose that the binding of each stator-unit is enhanced by the force it develops. Furthermore, FliL does not play a significant role in motor function in E. coli.
format	article
author	Ravi Chawla Katie M. Ford Pushkar P. Lele
author_facet	Ravi Chawla Katie M. Ford Pushkar P. Lele
author_sort	Ravi Chawla
title	Torque, but not FliL, regulates mechanosensitive flagellar motor-function
title_short	Torque, but not FliL, regulates mechanosensitive flagellar motor-function
title_full	Torque, but not FliL, regulates mechanosensitive flagellar motor-function
title_fullStr	Torque, but not FliL, regulates mechanosensitive flagellar motor-function
title_full_unstemmed	Torque, but not FliL, regulates mechanosensitive flagellar motor-function
title_sort	torque, but not flil, regulates mechanosensitive flagellar motor-function
publisher	Nature Portfolio
publishDate	2017
url	https://doaj.org/article/d5b89c12869d4a4882eb491dd6fe1569
work_keys_str_mv	AT ravichawla torquebutnotflilregulatesmechanosensitiveflagellarmotorfunction AT katiemford torquebutnotflilregulatesmechanosensitiveflagellarmotorfunction AT pushkarplele torquebutnotflilregulatesmechanosensitiveflagellarmotorfunction
_version_	1718388545053261824

Torque, but not FliL, regulates mechanosensitive flagellar motor-function

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