Perturbation of the yeast N-acetyltransferase NatB induces elevation of protein phosphorylation levels

BMC Genomics. 2010 Dec 2;11:685. doi: 10.1186/1471-2164-11-685.

Abstract

Background: The addition of an acetyl group to protein N-termini is a widespread co-translational modification. NatB is one of the main N-acetyltransferases that targets a subset of proteins possessing an N-terminal methionine, but so far only a handful of substrates have been reported. Using a yeast nat3Δ strain, deficient for the catalytic subunit of NatB, we employed a quantitative proteomics strategy to identify NatB substrates and to characterize downstream effects in nat3Δ.

Results: Comparing by proteomics WT and nat3Δ strains, using metabolic 15N isotope labeling, we confidently identified 59 NatB substrates, out of a total of 756 detected acetylated protein N-termini. We acquired in-depth proteome wide measurements of expression levels of about 2580 proteins. Most remarkably, NatB deletion led to a very significant change in protein phosphorylation.

Conclusions: Protein expression levels change only marginally in between WT and nat3Δ. A comparison of the detected NatB substrates with their orthologous revealed remarkably little conservation throughout the phylogenetic tree. We further present evidence of post-translational N-acetylation on protein variants at non-annotated N-termini. Moreover, analysis of downstream effects in nat3Δ revealed elevated protein phosphorylation levels whereby the kinase Snf1p is likely a key element in this process.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylation
  • Acetyltransferases / chemistry
  • Acetyltransferases / metabolism*
  • Amino Acid Sequence
  • Conserved Sequence / genetics
  • Molecular Sequence Data
  • Mutant Proteins / metabolism
  • Mutation / genetics
  • Peptides / chemistry
  • Peptides / metabolism
  • Phosphoproteins / metabolism
  • Phosphorylation
  • Protein Kinases / metabolism
  • Saccharomyces cerevisiae / enzymology*
  • Saccharomyces cerevisiae Proteins / metabolism*
  • Species Specificity
  • Substrate Specificity
  • Up-Regulation / genetics

Substances

  • Mutant Proteins
  • Peptides
  • Phosphoproteins
  • Saccharomyces cerevisiae Proteins
  • Acetyltransferases
  • NatB protein, S cerevisiae
  • Protein Kinases