Tyrosine phosphorylation-dependent localization of TmaR that controls activity of a major bacterial sugar regulator by polar sequestration

Tamar Szoke, Nitsan Albocher, Sutharsan Govindarajan, Anat Nussbaum-Shochat, Orna Amster-Choder*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


The poles of Escherichia coli cells are emerging as hubs for major sensory systems, but the polar determinants that allocate their components to the pole are largely unknown. Here, we describe the discovery of a previously unannotated protein, TmaR, which localizes to the E. coli cell pole when phosphorylated on a tyrosine residue. TmaR is shown here to control the subcellular localization and activity of the general PTS protein Enzyme I (EI) by binding and polar sequestration of EI, thus regulating sugar uptake and metabolism. Depletion or overexpression of TmaR results in EI release from the pole or enhanced recruitment to the pole, which leads to increasing or decreasing the rate of sugar consumption, respectively. Notably, phosphorylation of TmaR is required to release EI and enable its activity. Like TmaR, the ability of EI to be recruited to the pole depends on phosphorylation of one of its tyrosines. In addition to hyperactivity in sugar consumption, the absence of TmaR also leads to detrimental effects on the ability of cells to survive in mild acidic conditions. Our results suggest that this survival defect, which is sugar- and EI-dependent, reflects the difficulty of cells lacking TmaR to enter stationary phase. Our study identifies TmaR as the first, to our knowledge, E. coli protein reported to localize in a tyrosine-dependent manner and to control the activity of other proteins by their polar sequestration and release.

Original languageAmerican English
Article numbere2016017118
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number2
StatePublished - 12 Jan 2021

Bibliographical note

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  • Bacterial polarity
  • Cell pole
  • PTS system
  • Protein localization
  • Tyrosine phosphorylation


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