The Histidine Kinase CckA Is Directly Inhibited by a Response Regulator-like Protein in a Negative Feedback Loop

Vega-Baray, Benjamín; Domenzain, Clelia; Poggio, Sebastián; Dreyfus, Georges; Camarena, Laura

doi:10.1128/mbio.01481-22

Cited by 2 publications

(1 citation statement)

References 94 publications

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“…Phylogenetic analyses have shown that the fla1 genes originated from a horizontal transfer event whereas the fla2 genes are the vertically inherited genes in the α-proteobacteria linage [68]. So far, the Fla2 flagellum has been studied in mutant strains carrying two different mutations, one prevents the expression of Fla1 by removing the gene encoding for the Fla1-master regulator FleQ, and the other, is a gain of function mutation in CckA or a deleterious mutation in its negative regulator Osp [70][71][72].…”

Section: Introductionmentioning

confidence: 99%

Rotation of the Fla2 flagella of Cereibacter sphaeroides requires the periplasmic proteins MotK and MotE that interact with the flagellar stator protein MotB2

Vélez-González,

Marcos-Vilchis,

Vega-Baray

et al. 2024

PLoS ONE

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The bacterial flagellum is a complex structure formed by more than 25 different proteins, this appendage comprises three conserved structures: the basal body, the hook and filament. The basal body, embedded in the cell envelope, is the most complex structure and houses the export apparatus and the motor. In situ images of the flagellar motor in different species have revealed a huge diversity of structures that surround the well-conserved periplasmic components of the basal body. The identity of the proteins that form these novel structures in many cases has been elucidated genetically and biochemically, but in others they remain to be identified or characterized. In this work, we report that in the alpha proteobacteria Cereibacter sphaeroides the novel protein MotK along with MotE are essential for flagellar rotation. We show evidence that these periplasmic proteins interact with each other and with MotB2. Moreover, these proteins localize to the flagellated pole and MotK localization is dependent on MotB2 and MotA2. These results together suggest that the role of MotK and MotE is to activate or recruit the flagellar stators to the flagellar structure.

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Section: Introductionmentioning

confidence: 99%

Rotation of the Fla2 flagella of Cereibacter sphaeroides requires the periplasmic proteins MotK and MotE that interact with the flagellar stator protein MotB2

Vélez-González,

Marcos-Vilchis,

Vega-Baray

et al. 2024

PLoS ONE

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CerM and Its Antagonist CerN Are New Components of the Quorum Sensing System in Cereibacter sphaeroides, Signaling to the CckA/ChpT/CtrA System

Hernández‐Valle,

Vega‐Baray,

Poggio

et al. 2024

MicrobiologyOpen

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Cereibacter sphaeroides has a quorum sensing (QS) system that has been partially characterized. Using a bioinformatic approach, six LuxR homologs and one homolog of the acylhomoserine lactone synthase were identified in this bacterium, including the previously characterized CerR and CerI proteins. This study focused on determining the roles of two LuxR homologs, CerM and CerN. CerN lacks the HTH domain and, together with CerM, controls the expression of ctrA, which is part of the TCS CckA/ChpT/CtrA. CtrA is widely conserved in alpha‐proteobacteria and regulates flagellar motility and other cellular processes. Genetic and biochemical data suggest that CerM indirectly represses ctrA expression, which is counteracted by its interaction with CerN‐AHL. A transcriptomic study identified 181 genes regulated by CerM/CerN, with a conserved sequence in their regulatory regions likely indicating the CerM binding site. This hypothesis was supported by in vitro and in vivo DNA–protein interaction assays. Our results identified a transcription factor that could connect the QS system with the regulation of the two‐component system CckA/ChpT/CtrA.

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The Histidine Kinase CckA Is Directly Inhibited by a Response Regulator-like Protein in a Negative Feedback Loop

Abstract: The two-component systems (TCS) in bacteria in its simplest architecture consist of a histidine kinase (HK) and a response regulator (RR). In response to a specific stimulus, the HK is activated and drives phosphorylation of the RR, which is responsible of generating an adaptive response.

Cited by 2 publications

References 94 publications

Rotation of the Fla2 flagella of Cereibacter sphaeroides requires the periplasmic proteins MotK and MotE that interact with the flagellar stator protein MotB2

Rotation of the Fla2 flagella of Cereibacter sphaeroides requires the periplasmic proteins MotK and MotE that interact with the flagellar stator protein MotB2

CerM and Its Antagonist CerN Are New Components of the Quorum Sensing System in Cereibacter sphaeroides, Signaling to the CckA/ChpT/CtrA System

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