Post-translational modification of RNase R is regulated by stress-dependent reduction in the acetylating enzyme Pka (YfiQ)

Wenxing Liang, Murray P. Deutscher

Research output: Contribution to journalArticle

38 Scopus citations

Abstract

RNase R is a processive exoribonuclease that plays an important role in degradation of structured RNAs in Escherichia coli. RNase R is unstable in exponential phase cells; however, under certain stress conditions, RNase R levels increase dramatically due to its stabilization. Binding of tmRNA and SmpB to the C-terminal region of RNase R is required for its instability, and this binding is regulated by acetylation of a single residue, Lys544, in exponential phase cells. RNase R is not acetylated in stationary phase. We show here that only exponential phase RNase R is acetylated because the modifying enzyme, protein lysine acetyltransferase, Pka (YfiQ), is absent from late exponential and stationary phase cells. As a consequence, newly synthesized RNase R remains unmodified. Together with the turnover of preexisting acetylated RNase R, no modified RNase R remains in stationary phase. We find that RNase R in cold-shocked cells also lacks the acetyl modification due to the absence of Pka. These data indicate that RNase R stability depends on Pka, which itself is regulated under stress conditions.

Original languageEnglish (US)
Pages (from-to)37-41
Number of pages5
JournalRNA
Volume18
Issue number1
DOIs
StatePublished - Jan 2012

Keywords

  • Escherichia coli
  • Post-translational modification
  • Protein stability
  • Ribonuclease

ASJC Scopus subject areas

  • Molecular Biology

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