Homocysteine thiolactone affects protein ubiquitination in yeast.
The formation of homocysteine thiolactone (HcyTl) from homocysteine occurs in all examined so far organisms including bacteria, yeast, and humans. Protein N-homocysteinylation at the ε-amino group of lysine is an adverse result of HcyTl accumulation. Since tagging of proteins by ubiquitination before their proteasomal degradation takes place at the same residue, we wondered how N-homocysteinylation may affect the ubiquitination of proteins. We used different yeast strains carrying mutations in genes involved in the homocysteine metabolism. We found positive correlation between the concentration of endogenous HcyTl and the concentration of ubiquitinated proteins. This suggests that N-homocysteinylation of proteins apparently does not preclude but rather promotes their decomposition.
Poznań University of Life Sciences, Poznań, Poland.
Ewa
E
Bretes
Jarosław
J
Zimny
D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D006710:Homocysteine / Q000031:analogs & derivatives* / Q000378:metabolism*; D060847:Metabolic Engineering; D009154:Mutation; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D059748:Proteolysis; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D057149:Ubiquitinated Proteins / Q000235:genetics / Q000378:metabolism*; D054875:Ubiquitination
D005656:Fungal Proteins; D057149:Ubiquitinated Proteins; D006710:Homocysteine; C007957:homocysteine thiolactone; D046988:Proteasome Endopeptidase Complex