Global regulatory mutations in csrA and rpoS cause severe central carbon stress in Escherichia coli in the presence of acetate

Bangdong Wei, Sooan Shin, David Laporte, Alan J. Wolfe, Tony Romeo

Research output: Contribution to journalArticlepeer-review

87 Scopus citations

Abstract

The csrA gene encodes a small RNA-binding protein, which acts as a global regulator in Escherichia coli and other bacteria (T. Romeo, Mol. Microbiol. 29:1321-1330, 1998). Its key regulatory role in central carbon metabolism, both as an activator of glycolysis and as a potent repressor of glycogen biosynthesis and gluconeogenesis, prompted us to examine the involvement of csrA in acetate metabolism and the tricarboxylic acid (TCA) cycle. We found that growth of csrA rpoS mutant strains was very poor on acetate as a sole carbon source. Surprisingly, growth also was inhibited specifically by the addition of modest amounts of acetate to rich media (e.g., tryptone broth). Cultures grown in the presence of ≥25 mM acetate consisted substantially of glycogen biosynthesis (glg) mutants, which were no longer inhibited by acetate. Several classes of glg mutations were mapped to known and novel loci. Several hypotheses were examined to provide further insight into the effects of acetate on growth and metabolism in these strains. We determined that csrA positively regulates acs (acetyl-coenzyme A synthetase; Acs) expression and isocitrate lyase activity without affecting key TCA cycle enzymes or phosphotransacetylase. TCA cycle intermediates or pyruvate, but not glucose, galactose, or glycerol, restored growth and prevented the glg mutations in the presence of acetate. Furthermore, amino acid uptake was inhibited by acetate specifically in the csrA rpoS strain. We conclude that central carbon flux imbalance, inhibition of amino acid uptake, and a deficiency in acetate metabolism apparently are combined to cause metabolic stress by depleting the TCA cycle.

Original languageEnglish (US)
Pages (from-to)1632-1640
Number of pages9
JournalJournal of bacteriology
Volume182
Issue number6
DOIs
StatePublished - Mar 2000

Fingerprint Dive into the research topics of 'Global regulatory mutations in csrA and rpoS cause severe central carbon stress in Escherichia coli in the presence of acetate'. Together they form a unique fingerprint.

Cite this