ABSTRACT
Deubiquitylating enzymes (DUBs) enhance the dynamics of the versatile ubiquitin (Ub) code by reversing and regulating cellular ubiquitylation processes at multiple levels. Here we discovered that the uncharacterized human protein ZUFSP (zinc finger with UFM1-specific peptidase domain protein/C6orf113/ZUP1), which has been annotated as a potentially inactive UFM1 protease, and its fission yeast homolog Mug105 define a previously unrecognized class of evolutionarily conserved cysteine protease DUBs. Human ZUFSP selectively interacts with and cleaves long K63-linked poly-Ub chains by means of tandem Ub-binding domains, whereas it displays poor activity toward mono- or di-Ub substrates. In cells, ZUFSP is recruited to and regulates K63-Ub conjugates at genotoxic stress sites, promoting chromosome stability upon replication stress in a manner dependent on its catalytic activity. Our findings establish ZUFSP as a new type of linkage-selective cysteine peptidase DUB with a role in genome maintenance pathways.
Subject(s)
Bone Neoplasms/enzymology , DNA Damage , Deubiquitinating Enzymes/metabolism , Genomic Instability , Osteosarcoma/enzymology , Polyubiquitin/metabolism , Retinal Pigment Epithelium/enzymology , Binding Sites , Bone Neoplasms/genetics , Cell Line, Tumor , Deubiquitinating Enzymes/genetics , HEK293 Cells , Humans , Lysine , Osteosarcoma/genetics , Polyubiquitin/genetics , Protein Binding , Protein Interaction Domains and Motifs , Substrate Specificity , UbiquitinationABSTRACT
DNA-protein crosslinks (DPCs) obstruct essential DNA transactions, posing a serious threat to genome stability and functionality. DPCs are proteolytically processed in a ubiquitin- and DNA replication-dependent manner by SPRTN and the proteasome but can also be resolved via targeted SUMOylation. However, the mechanistic basis of SUMO-mediated DPC resolution and its interplay with replication-coupled DPC repair remain unclear. Here, we show that the SUMO-targeted ubiquitin ligase RNF4 defines a major pathway for ubiquitylation and proteasomal clearance of SUMOylated DPCs in the absence of DNA replication. Importantly, SUMO modifications of DPCs neither stimulate nor inhibit their rapid DNA replication-coupled proteolysis. Instead, DPC SUMOylation provides a critical salvage mechanism to remove DPCs formed after DNA replication, as DPCs on duplex DNA do not activate interphase DNA damage checkpoints. Consequently, in the absence of the SUMO-RNF4 pathway cells are able to enter mitosis with a high load of unresolved DPCs, leading to defective chromosome segregation and cell death. Collectively, these findings provide mechanistic insights into SUMO-driven pathways underlying replication-independent DPC resolution and highlight their critical importance in maintaining chromosome stability and cellular fitness.
Subject(s)
DNA Repair , DNA Replication , Nuclear Proteins/metabolism , Signal Transduction , Small Ubiquitin-Related Modifier Proteins/metabolism , Transcription Factors/metabolism , Genomic Instability , Humans , Protein Binding , Protein Processing, Post-Translational , Sumoylation , Ubiquitin/metabolism , UbiquitinationABSTRACT
Climate change is the greatest challenge of our time, and drastic climate action is needed urgently across industries and sectors to prevent the worst in terms of consequences. Although academic research brings great benefits to society, it leaves behind a considerable environmental footprint at the same time. This is particularly true for lab research within the life sciences. To reduce the climate impact of academic research, both bottom-up and top-down strategies are necessary. On the bottom-up side, 'green' grassroots groups are emerging in academia, but most institutions fail to nurture and harness their potential for driving change. We report findings from a survey of 63 such grassroots groups operating in academic environments, highlighting that their main challenges in making research more sustainable include lack of time, budget, involvement in management decisions and support from management. For the first time, we map the inception, goals and structure of green grassroots groups in academia and outline concrete steps in overcoming barriers to harvest their full potential, thus making academic research fit for the future.
Subject(s)
Climate ChangeABSTRACT
DNA-protein crosslinks (DPCs) are highly cytotoxic lesions that obstruct essential DNA transactions and whose resolution is critical for cell and organismal fitness. However, the mechanisms by which cells respond to and overcome DPCs remain incompletely understood. Recent studies unveiled a dedicated DPC repair pathway in higher eukaryotes involving the SprT-type metalloprotease SPRTN/DVC1, which proteolytically processes DPCs during DNA replication in a ubiquitin-regulated manner. Here, we show that chemically induced and defined enzymatic DPCs trigger potent chromatin SUMOylation responses targeting the crosslinked proteins and associated factors. Consequently, inhibiting SUMOylation compromises DPC clearance and cellular fitness. We demonstrate that ACRC/GCNA family SprT proteases interact with SUMO and establish important physiological roles of Caenorhabditis elegans GCNA-1 and SUMOylation in promoting germ cell and embryonic survival upon DPC formation. Our findings provide first global insights into signaling responses to DPCs and reveal an evolutionarily conserved function of SUMOylation in facilitating responses to these lesions in metazoans that may complement replication-coupled DPC resolution processes.