N-terminal domain of nuclear IL-1α shows structural similarity to the C-terminal domain of Snf1 and binds to the HAT/core module of the SAGA complex

PLoS One. 2012;7(8):e41801. doi: 10.1371/journal.pone.0041801. Epub 2012 Aug 6.

Abstract

Interleukin-1α (IL-1α) is a proinflammatory cytokine and a key player in host immune responses in higher eukaryotes. IL-1α has pleiotropic effects on a wide range of cell types, and it has been extensively studied for its ability to contribute to various autoimmune and inflammation-linked disorders, including rheumatoid arthritis, Alzheimer's disease, systemic sclerosis and cardiovascular disorders. Interestingly, a significant proportion of IL-1α is translocated to the cell nucleus, in which it interacts with histone acetyltransferase complexes. Despite the importance of IL-1α, little is known regarding its binding targets and functions in the nucleus. We took advantage of the histone acetyltransferase (HAT) complexes being evolutionarily conserved from yeast to humans and the yeast SAGA complex serving as an epitome of the eukaryotic HAT complexes. Using gene knock-out technique and co-immunoprecipitation of the IL-1α precursor with TAP-tagged subunits of the yeast HAT complexes, we mapped the IL-1α-binding site to the HAT/Core module of the SAGA complex. We also predicted the 3-D structure of the IL-1α N-terminal domain, and by employing structure similarity searches, we found a similar structure in the C-terminal regulatory region of the catalytic subunit of the AMP-activated/Snf1 protein kinases, which interact with HAT complexes both in mammals and yeast, respectively. This finding is further supported with the ability of the IL-1α precursor to partially rescue growth defects of snf1Δ yeast strains on media containing 3-Amino-1,2,4-triazole (3-AT), a competitive inhibitor of His3. Finally, the careful evaluation of our data together with other published data in the field allows us to hypothesize a new function for the ADA complex in SAGA complex assembly.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • AMP-Activated Protein Kinases / chemistry
  • AMP-Activated Protein Kinases / metabolism
  • Binding Sites
  • Cell Nucleus / metabolism*
  • Computational Biology
  • Gene Knockout Techniques
  • Histone Acetyltransferases / metabolism*
  • Humans
  • Immunoprecipitation
  • Interleukin-1alpha / chemistry*
  • Interleukin-1alpha / metabolism*
  • Models, Biological
  • Protein Binding
  • Protein Precursors / chemistry
  • Protein Precursors / metabolism
  • Protein Serine-Threonine Kinases / chemistry*
  • Protein Serine-Threonine Kinases / metabolism*
  • Protein Structure, Tertiary
  • Protein Subunits / metabolism
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins / metabolism*
  • Signal Transduction
  • Structural Homology, Protein
  • Structure-Activity Relationship
  • Subcellular Fractions / metabolism
  • Trans-Activators / metabolism*

Substances

  • Interleukin-1alpha
  • Protein Precursors
  • Protein Subunits
  • SAGA complex, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Trans-Activators
  • Histone Acetyltransferases
  • SNF1-related protein kinases
  • Protein Serine-Threonine Kinases
  • AMP-Activated Protein Kinases

Grants and funding

This project was supported by the Ministry of Health of the Czech Republic, IGA (grant NS/9819) and also partially supported by the Ministry of Education, Youth and Sports of the Czech Republic (grant MSM0021620858) and by the Charles University institutional grant SVV-2012-265202. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.