Coupling chemosensory array formation and localization.

Alejandra Alvarado,Wen Yang,Matthew K Waldor,Simon Ringgaard,Petra Mann,Ariane Briegel,Andreas Kjær

doi:10.7554/elife.31058

Abstract

Chemotaxis proteins organize into large, highly ordered, chemotactic signaling arrays, which in Vibrio species are found at the cell pole. Proper localization of signaling arrays is mediated by ParP, which tethers arrays to a cell pole anchor, ParC. Here we show that ParP's C-terminus integrates into the core-unit of signaling arrays through interactions with MCP-proteins and CheA. Its intercalation within core-units stimulates array formation, whereas its N-terminal interaction domain enables polar recruitment of arrays and facilitates its own polar localization. Linkage of these domains within ParP couples array formation and localization and results in controlled array positioning at the cell pole. Notably, ParP's integration into arrays modifies its own and ParC's subcellular localization dynamics, promoting their polar retention. ParP serves as a critical nexus that regulates the localization dynamics of its network constituents and drives the localized assembly and stability of the chemotactic machinery, resulting in proper cell pole development.

Highlights

Chemotaxis is one of the primary means by which motile bacteria sense, respond, and adapt to changing environmental conditions
In the polarly flagellated pathogens Vibrio cholerae and Vibrio parahaemolyticus, we recently reported that chemosensory arrays are exclusively localized at one or both cell poles by a mechanism that depends on the partner proteins ParC and ParP, both of which are encoded within the chemotaxis operon (Ringgaard et al, 2011; Yamaichi et al, 2012; Ringgaard et al, 2014)
In a strain lacking cheA1, YFP-CheW1 still formed clusters at the cells poles in a manner indistinguishable to that observed in wild-type cells (Figure 1C–E), suggesting that chemotaxis arrays still form in the absence of CheA

Summary

Introduction

Chemotaxis is one of the primary means by which motile bacteria sense, respond, and adapt to changing environmental conditions This process enables motile bacteria to perceive changes in local concentrations of chemicals; as a result, they can bias their movement away from unfavorable chemical stimuli and towards more favorable compounds (Wadhams and Armitage, 2004; Sourjik and Armitage, 2010). The chemotaxis signaling cascade is initiated upon the detection of chemotactic stimuli by methyl-accepting chemotaxis proteins (MCPs). These membrane-spanning receptors interact with a cytoplasmic histidine kinase, CheA, while the adaptor protein CheW stabilizes this interaction and participates in regulating CheA kinase activity (Ortega et al, 2013; Parkinson et al, 2015). Phosphorylated CheY induces a change in flagellar rotation and in the direction of bacterial swimming, which over time results in net movement towards a more favorable environment (Wadhams and Armitage, 2004; Sourjik and Armitage, 2010)

Methods

Results

Conclusion