Oral Presentation 26th Annual Lorne Proteomics Symposium 2021

Methylation, phosphorylation and their crosstalk on translation-associated proteins (#2)

Joshua J Hamey 1 , Amy Nguyen 1 , Daniela-Lee Smith 1 , Marc R Wilkins 1
  1. Systems Biology Initiative, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia

Protein translation is a central process in the cell. It is currently emerging that protein translation is extensively regulated. This is mediated in large part by post-translational modifications (PTMs), in particular methylation and phosphorylation. However, there remains much to be understood about the prevalence and crosstalk of these two PTMs on translation-associated proteins. Through PTM enrichment, heavy methyl SILAC and mass spectrometric analysis in Saccharomyces cerevisiae, we uncovered dozens of novel methylation and phosphorylation sites on translation-associated proteins. We also discovered several instances where these PTMs co-occur on the same protein molecule, indicating co-regulation and potential crosstalk. Arginine methylation, in particular, was found to be pervasive across arginine-glycine repeat regions of proteins associated with translation and ribosome biogenesis. We showed that for one protein, yeast fibrillarin, phospho-methyl crosstalk occurs at serine-arginine-glycine-glycine (SRGG) motifs, where phosphorylation strongly inhibits the deposition of methylation (1). We also discovered several phospho-methyl co-occurrences on the highly conserved and abundant eukaryotic elongation factor 1A (eEF1A) (2). Through in vivo mutagenesis and mass spectrometry, we showed that phosphorylation inhibits nearby methylation, but that methylation does not affect nearby phosphorylation. Overall, our results indicate that phospho-methyl crosstalk is more widespread on translation-associated proteins than previously appreciated, and is likely to be central to the regulation of protein translation.

  1. Smith, D. L., Erce, M. A., Lai, Y. W., Tomasetig, F., Hart-Smith, G., Hamey, J. J., & Wilkins, M. R. (2020). Crosstalk of phosphorylation and arginine methylation in disordered SRGG repeats of Saccharomyces cerevisiae fibrillarin and its association with nucleolar localization. Journal of molecular biology, 432(2), 448-466.
  2. Hamey, J. J., & Wilkins, M. R. (2018). Methylation of elongation factor 1A: where, who, and why?. Trends in biochemical sciences, 43(3), 211-223.