Biology subjects

Pick, E.

Publications and source records attributed to Pick, E..

3 recordsLinked to original sources

bioRxiv2024

Redox-driven control of Yuh1/UCHL3 impacts mitochondrial health via NEDD8/Rub1 pathway

The ubiquitin-like protein NEDD8/Rub1 undergoes processing by the enzyme Yuh1/UCHL3 to become functional. While the processed NEDD8/Rub1 modifies Cullin-RING E3 ligases (CRLs) among all studied organisms, its role in facilitating CRL-based substrate degradation is absent in S. cerevisiae. This prompts questions about NEDD8/Rub1 functionality if it does not activate CRLs universally. Previous studies revealed that increased production of reactive oxygen species (ROS) during the glycolysis to mitochondrial respiration transition inhibits cullin NEDDylation in S. cerevisiae, yet the specific affected enzymes remain unidentified. Here, we investigate how redox changes affect Yuh1 activity, revealing a thiol-based redox switch modulating its catalytic function in response to ROS. Temporal inactivation of Yuh1 fine-tunes NEDD8/Rub1 mature and precursor species, both crucial for maintaining mitochondrial integrity and enhancing oxidative stress resilience. These findings unveil a novel role for Rub1/NEDD8 beyond CRL activation, linking redox signaling to NEDD8/Rub1 pathways. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=137 SRC="FIGDIR/small/594945v1_ufig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@1ce0c41org.highwire.dtl.DTLVardef@8690bdorg.highwire.dtl.DTLVardef@8898c6org.highwire.dtl.DTLVardef@1e61a85_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2020

Rub1/NEDD8, a ubiquitin-like modifier, is also a ubiquitin modifier

Of all ubiquitin-like small protein modifiers, Rub1/NEDD8 is the closest kin of ubiquitin in sequence and in structure. Despite their profound similarities, prevalence of ubiquitin and of Rub1 is starkly different: targets of ubiquitin modification reach into the thousands, whereas unique targets of Rub1/NEDD8 appear limited to one family of proteins, Cullins. This distinction is likely due to dedicated E1 activating enzymes that select either one or the other and relay the modifier until it is covalently attached to a target. To convert typical neddylation targets for modification by ubiquitin, and vice versa, we designed reciprocal substitutions at position 72 of Rub1 and of ubiquitin to render them substrates for activation by their non-cognate E1 activating enzymes. We found that this single amino acid is sufficient to distinguish between Ub and Rub1 in living cells, and determine their targets. Thus, modification of Cullins by UbR72T could compensate for loss of Rub1, even as it maintained its ability to polymerize and direct conjugates for degradation. Conversely, Rub1T72R activated by ubiquitin-activating enzyme entered into the ubiquitination cascade, however was not efficiently polymerized, essentially capping polyubiquitin chains. Upon shortage of free ubiquitin under stress, even native Rub1 spilled-over into the ubiquitinome suppressing polyubiquitination. By contrast, the need to maintain monomeric modifications on unique targets is a likely explanation for why the Rub1-activating enzyme strictly discriminates against ubiquitin. Swapping Rub1 and ubiquitin signals uncovered a reason for maintaining two separate pathways across eukaryotic kingdom.

biochemistry↗

bioRxiv2019

A molecular switch for Cdc48 activity and localization during oxidative stress and aging

Control over a healthy proteome begins with the birth of the polypeptide chain and ends with coordinated protein degradation. One of the major players in eukaryotic protein degradation is the essential and highly conserved ATPase, Cdc48 (p97/VCP in mammals). Cdc48 mediates clearance of misfolded proteins from the nucleus, cytosol, ER, mitochondria, and more. Here we dissect the crosstalk between cellular oxidation and Cdc48 activity by identification of a redox-sensitive site, Cys115. By integrating proteomics, biochemistry, microscopy, and bioinformatics, we show that removal of Cys115s redox-sensitive thiol group leads to accumulation of Cdc48 in the nucleus and consequently, results in severe defects in the oxidative stress response, mitochondrial fragmentation, and a decrease in ERAD and sterol biogenesis. We have thus identified a unique redox switch in Cdc48, which may provide a clearer picture of the importance of Cdc48s localization in maintaining a \"healthy\" proteome during oxidative stress and chronological aging in yeast.

molecular biology↗