Mechanism of activation of methyltransferases involved in translation by the Trm112 'hub' protein

Nucleic Acids Res. 2011 Aug;39(14):6249-59. doi: 10.1093/nar/gkr176. Epub 2011 Apr 7.

Abstract

Methylation is a common modification encountered in DNA, RNA and proteins. It plays a central role in gene expression, protein function and mRNA translation. Prokaryotic and eukaryotic class I translation termination factors are methylated on the glutamine of the essential and universally conserved GGQ motif, in line with an important cellular role. In eukaryotes, this modification is performed by the Mtq2-Trm112 holoenzyme. Trm112 activates not only the Mtq2 catalytic subunit but also two other tRNA methyltransferases (Trm9 and Trm11). To understand the molecular mechanisms underlying methyltransferase activation by Trm112, we have determined the 3D structure of the Mtq2-Trm112 complex and mapped its active site. Using site-directed mutagenesis and in vivo functional experiments, we show that this structure can also serve as a model for the Trm9-Trm112 complex, supporting our hypothesis that Trm112 uses a common strategy to activate these three methyltransferases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Catalytic Domain
  • Crystallography
  • Enzyme Activation
  • Fungal Proteins / chemistry
  • Gene Deletion
  • Models, Molecular
  • Mutagenesis, Site-Directed
  • Protein Binding
  • Protein Biosynthesis
  • Protein Methyltransferases / chemistry*
  • Protein Methyltransferases / genetics
  • Protein Subunits / chemistry*
  • Protein Subunits / genetics
  • S-Adenosylmethionine / chemistry
  • Saccharomyces cerevisiae Proteins / genetics
  • tRNA Methyltransferases / genetics

Substances

  • Fungal Proteins
  • Protein Subunits
  • Saccharomyces cerevisiae Proteins
  • S-Adenosylmethionine
  • Protein Methyltransferases
  • TRM9 protein, S cerevisiae
  • tRNA Methyltransferases
  • Trm112 protein, S cerevisiae