Proteome-Wide Analysis of Protein Lysine N-Homocysteinylation in Saccharomyces cerevisiae

Joanna Perla-Kaján, Agata Malinowska, Jaroslaw Zimny, Dominik Cysewski, Joanna Suszyńska-Zajczyk, Hieronim Jakubowski

Research output: Contribution to journalArticlepeer-review


Protein N-homocysteinylation by a homocysteine (Hcy) metabolite, Hcy-thiolactone, is an emerging post-translational modification (PTM) that occurs in all tested organisms and has been linked to human diseases. The yeast Saccharomyces cerevisiae is widely used as a model eukaryotic organism in biomedical research, including studies of protein PTMs. However, patterns of global protein N-homocysteinylation in yeast are not known. Here, we identified 68 in vivo and 197 in vitro N-homocysteinylation sites at protein lysine residues (N-Hcy-Lys). Some of the N-homocysteinylation sites overlap with other previously identified PTM sites. Protein N-homocysteinylation in vivo, induced by supplementation of yeast cultures with Hcy, which elevates Hcy-thiolactone levels, was accompanied by significant changes in the levels of 70 yeast proteins (38 up-regulated and 32 down-regulated) involved in the ribosomal structure, amino acid biosynthesis, and basic cellular pathways. Our study provides the first global survey of N-homocysteinylation and accompanying changes in the yeast proteome caused by elevated Hcy level. These findings suggest that protein N-homocysteinylation and dysregulation of cellular proteostasis may contribute to the toxicity of Hcy in yeast. Homologous proteins and N-homocysteinylation sites are likely to be involved in Hcy-related pathophysiology in humans and experimental animals. Data are available via ProteomeXchange with identifier PXD020821.

Original languageEnglish (US)
Pages (from-to)2458-2476
Number of pages19
JournalJournal of Proteome Research
Issue number5
StatePublished - May 7 2021

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Chemistry(all)


  • homocysteine
  • homocysteine thiolactone
  • mass spectrometry
  • protein N-homocysteinylation
  • yeast proteome


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