Phosphorylation of DegU is essential for activation of amyE expression in Bacillus subtilis

J Biosci. 2014 Dec;39(5):747-52. doi: 10.1007/s12038-014-9481-5.

Abstract

Alpha-amylase (amyE) is one of the major exo-enzymes secreted by Bacillus subtilis during the post-exponential phase. The DegS-DegU two-component system regulates expression of majority of post-exponentially expressed genes in B. subtilis. It has been demonstrated that varying levels of the phosphorylated form of DegU (DegU-P) control different cellular processes. Exo-protease production is observed when effective concentration of DegU-P rises in the cell, whereas swarming motility is favoured at very low amounts of DegU-P. In this study we show that like other exo-proteases, expression of amyE is positively regulated by increase in DegU-P levels in the cell. We also demonstrate that residues at the DNA-binding helix-turn-helix (HTH) motif of DegU are necessary for the amyE expression. This observation is further reinforced by demonstrating the direct interaction of DegU on amyE promoter.

MeSH terms

  • Amino Acid Motifs
  • Bacillus subtilis / enzymology
  • Bacillus subtilis / metabolism*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Base Sequence
  • Gene Expression Regulation, Bacterial
  • Genes, Bacterial
  • Molecular Sequence Data
  • Phosphorylation
  • Promoter Regions, Genetic
  • alpha-Amylases / genetics
  • alpha-Amylases / metabolism*

Substances

  • Bacterial Proteins
  • DegU protein, Bacteria
  • alpha-Amylases