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The Phosphohistidine Phosphatase SixA Targets a Phosphotransferase System

SixA, a well-conserved protein found in proteobacteria, actinobacteria, and cyanobacteria, is the only reported example of a bacterial phosphohistidine phosphatase. A single protein target of SixA has been reported to date: the Escherichia coli histidine kinase ArcB. The present work analyzes an Arc...

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Detalles Bibliográficos
Autores principales: Schulte, Jane E., Goulian, Mark
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Society for Microbiology 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6282199/
https://www.ncbi.nlm.nih.gov/pubmed/30482831
http://dx.doi.org/10.1128/mBio.01666-18
Descripción
Sumario:SixA, a well-conserved protein found in proteobacteria, actinobacteria, and cyanobacteria, is the only reported example of a bacterial phosphohistidine phosphatase. A single protein target of SixA has been reported to date: the Escherichia coli histidine kinase ArcB. The present work analyzes an ArcB-independent growth defect of a sixA deletion in E. coli. A screen for suppressors, analysis of various mutants, and phosphorylation assays indicate that SixA modulates phosphorylation of the nitrogen-related phosphotransferase system (PTS(Ntr)). The PTS(Ntr) is a widely conserved bacterial pathway that regulates diverse metabolic processes through the phosphorylation states of its protein components, EI(Ntr), NPr, and EIIA(Ntr), which receive phosphoryl groups on histidine residues. However, a mechanism for dephosphorylating this system has not been reported. The results presented here suggest a model in which SixA removes phosphoryl groups from the PTS(Ntr) by acting on NPr. This work uncovers a new role for the phosphohistidine phosphatase SixA and, through factors that affect SixA expression or activity, may point to additional inputs that regulate the PTS(Ntr).