Ubiquitin chain elongation enzyme Ufd2 regulates a subset of Doa10 substrates.
Ufd2 is the founding member of E4 enzymes that are specifically involved in ubiquitin chain elongation but whose roles in proteolysis remain scarce. Here, using a genome-wide screen, we identified one cellular target of yeast Ufd2 as the membrane protein Pex29. The ubiquitin chains assembled on Pex29 in vivo by Ufd2 mainly contain Lys-48 linkages. We found that the ubiquitin-protein E3 ligase for overexpressed Pex29 is Doa10, which is known to be involved in protein quality control. Interestingly, not all Doa10 substrates are regulated by Ufd2, suggesting that E4 involvement is not specific to a particular E3, but may depend on the spatial arrangement of the E3-substrate interaction. Cells lacking UFD2 elicit an unfolded protein response, expanding the physiological function of Ufd2. Our results lead to novel insights into the biological role of Ufd2 and further underscore the significance of Ufd2 in proteolysis.
Liu
Chang
C
Institute of Biotechnology, Department of Molecular Medicine, University of Texas Health Science Center, San Antonio, Texas 78245, USA.
van Dyk
Dewald
D
Xu
Ping
P
Choe
Vitnary
V
Pan
Haihui
H
Peng
Junmin
J
Andrews
Brenda
B
Rao
Hai
H
D015151:Immunoblotting; D008239:Lysine / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D010957:Plasmids; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D025801:Ubiquitin / Q000378:metabolism; D044763:Ubiquitin-Conjugating Enzymes / Q000502:physiology*; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*; D056811:Unfolded Protein Response
D008565:Membrane Proteins; C474735:PEX29 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D025801:Ubiquitin; D044763:Ubiquitin-Conjugating Enzymes; C091362:SSM4 protein, S cerevisiae; D044767:Ubiquitin-Protein Ligases; D046988:Proteasome Endopeptidase Complex; C114683:UFD2 protein, S cerevisiae; D008239:Lysine