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Novel MntR-independent mechanism of manganese homeostasis in Escherichia coli by the ribosome-associated protein HflX.

DIR@IMTECH: CSIR-Institute of Microbial Technology

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Title Novel MntR-independent mechanism of manganese homeostasis in Escherichia coli by the ribosome-associated protein HflX.
 
Creator Kaur, Gursharan
Sengupta, Sandeepan
Kumar, Vineet
Kumari, Aruna
Ghosh, Aditi
Parrack, Pradeep
Dutta, Dipak
 
Description Manganese is a micronutrient required for activities of several important enzymes under conditions of oxidative stress and iron starvation. In Escherichia coli, the manganese homeostasis network primarily constitutes a manganese importer (MntH) and an exporter (MntP), which are regulated by the MntR dual regulator. In this study, we find that deletion of E. coli hflX, which encodes a ribosome-associated GTPase with unknown function, renders extreme manganese sensitivity characterized by arrested cell growth, filamentation, lower rate of replication, and DNA damage. We demonstrate that perturbation by manganese induces unprecedented influx of manganese in ΔhflX cells compared to that in the wild-type E. coli strain. Interestingly, our study indicates that the imbalance in manganese homeostasis in the ΔhflX strain is independent of the MntR regulon. Moreover, the influx of manganese leads to a simultaneous influx of zinc and inhibition of iron import in ΔhflX cells. In order to review a possible link of HflX with the λ phage life cycle, we performed a lysis-lysogeny assay to show that the Mn-perturbed ΔhflX strain reduces the frequency of lysogenization of the phage. This observation raises the possibility that the induced zinc influx in the manganese-perturbed ΔhflX strain stimulates the activity of the zinc-metalloprotease HflB, the key determinant of the lysis-lysogeny switch. Finally, we propose that manganese-mediated autophosphorylation of HflX plays a central role in manganese, zinc, and iron homeostasis in E. coli cells.
 
Publisher Washington, DC : American Society for Microbiology
 
Date 2014-07
 
Type Article
PeerReviewed
 
Relation http://jb.asm.org/content/196/14/2587.long
http://crdd.osdd.net/open/1579/
 
Identifier Kaur, Gursharan and Sengupta, Sandeepan and Kumar, Vineet and Kumari, Aruna and Ghosh, Aditi and Parrack, Pradeep and Dutta, Dipak (2014) Novel MntR-independent mechanism of manganese homeostasis in Escherichia coli by the ribosome-associated protein HflX. Journal of bacteriology, 196 (14). pp. 2587-97. ISSN 1098-5530