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Genes Jan 2024DNA-protein crosslinks (DPCs) represent a unique and complex form of DNA damage formed by covalent attachment of proteins to DNA. DPCs are formed through a variety of... (Review)
Review
DNA-protein crosslinks (DPCs) represent a unique and complex form of DNA damage formed by covalent attachment of proteins to DNA. DPCs are formed through a variety of mechanisms and can significantly impede essential cellular processes such as transcription and replication. For this reason, anti-cancer drugs that form DPCs have proven effective in cancer therapy. While cells rely on numerous different processes to remove DPCs, the molecular mechanisms responsible for orchestrating these processes remain obscure. Having this insight could potentially be harnessed therapeutically to improve clinical outcomes in the battle against cancer. In this review, we describe the ways cells enzymatically process DPCs. These processing events include direct reversal of the DPC via hydrolysis, nuclease digestion of the DNA backbone to delete the DPC and surrounding DNA, proteolytic processing of the crosslinked protein, as well as covalent modification of the DNA-crosslinked proteins with ubiquitin, SUMO, and Poly(ADP) Ribose (PAR).
Topics: Ubiquitin; DNA Damage; Endonucleases; Hydrolysis; Proteolysis
PubMed: 38254974
DOI: 10.3390/genes15010085 -
Sub-cellular Biochemistry 2019Proteasomes are a class of protease that carry out the degradation of a specific set of cellular proteins. While essential for eukaryotic life, proteasomes are found... (Review)
Review
Proteasomes are a class of protease that carry out the degradation of a specific set of cellular proteins. While essential for eukaryotic life, proteasomes are found only in a small subset of bacterial species. In this chapter, we present the current knowledge of bacterial proteasomes, detailing the structural features and catalytic activities required to achieve proteasomal proteolysis. We describe the known mechanisms by which substrates are doomed for degradation, and highlight potential non-degradative roles for components of bacterial proteasome systems. Additionally, we highlight several pathways of microbial physiology that rely on proteasome activity. Lastly, we explain the various gaps in our understanding of bacterial proteasome function and emphasize several opportunities for further study.
Topics: Bacteria; Bacterial Proteins; Proteasome Endopeptidase Complex; Proteolysis
PubMed: 31939157
DOI: 10.1007/978-3-030-28151-9_11 -
Angewandte Chemie (International Ed. in... Jan 2024Proteolysis targeting chimera (PROTAC) is a state-of-the-art technology for ablating undruggable targets. A PROTAC degrader achieves targeted protein degradation (TPD)... (Review)
Review
Proteolysis targeting chimera (PROTAC) is a state-of-the-art technology for ablating undruggable targets. A PROTAC degrader achieves targeted protein degradation (TPD) through the simultaneous binding of a protein of interest (POI) and an E3 ligase to form a ternary complex. A nanofibril-based PROTAC strategy to form a polynary (E3) : PROTAC : (POI) complex has not been reported in the TPD field up to this point. A recent innovation shows that a POI ligand and E3 ligase ligand don't have to be within a fused degrader molecule. Instead, they can be recruited to cellular proximity by a self-assembly-driving peptide and click chemistry. The resulting nanofibrils can recruit multiple POI and E3 ligase molecules to form a polynary complex as a degradation center. The so-called Nano-PROTAC provides a novel approach for TPD in cancer therapy.
Topics: Proteolysis; Ligands; Ubiquitin-Protein Ligases; Peptides
PubMed: 38059785
DOI: 10.1002/anie.202316581 -
Journal of Medicinal Chemistry Jul 2023Within druggable target space, new small-molecule modalities, particularly covalent inhibitors and targeted degraders, have expanded the repertoire of medicinal... (Review)
Review
Within druggable target space, new small-molecule modalities, particularly covalent inhibitors and targeted degraders, have expanded the repertoire of medicinal chemists. Molecules with such modes of action have a large potential not only as drugs but also as chemical probes. Criteria have previously been established to describe the potency, selectivity, and properties of small-molecule probes that are qualified to enable the interrogation and validation of drug targets. These definitions have been tailored to reversibly acting modulators but fall short in their applicability to other modalities. While initial guidelines have been proposed, we delineate here a full set of criteria for the characterization of covalent, irreversible inhibitors as well as heterobifunctional degraders ("proteolysis-targeting chimeras", or PROTACs) and molecular glue degraders. We propose modified potency and selectivity criteria compared to those for reversible inhibitors. We discuss their relevance and highlight examples of suitable probe and pathfinder compounds.
Topics: Proteolysis; Ubiquitin-Protein Ligases
PubMed: 37403870
DOI: 10.1021/acs.jmedchem.3c00550 -
Expert Opinion on Drug Discovery Apr 2023Target protein degradation (TPD) provides a novel therapeutic modality, other than inhibition, through the direct depletion of target proteins. Two primary human protein... (Review)
Review
INTRODUCTION
Target protein degradation (TPD) provides a novel therapeutic modality, other than inhibition, through the direct depletion of target proteins. Two primary human protein homeostasis mechanisms are exploited: the ubiquitin-proteasome system (UPS) and the lysosomal system. TPD technologies based on these two systems are progressing at an impressive pace.
AREAS COVERED
This review focuses on the TPD strategies based on UPS and lysosomal system, mainly classified into three types: Molecular Glue (MG), PROteolysis Targeting Chimera (PROTAC), and lysosome-mediated TPD. Starting with a brief background introduction of each strategy, exciting examples and perspectives on these novel approaches are provided.
EXPERT OPINION
MGs and PROTACs are two major UPS-based TPD strategies that have been extensively investigated in the past decade. Despite some clinical trials, several critical issues remain, among which is emphasized by the limitation of targets. Recently developed lysosomal system-based approaches provide alternative solutions for TPD beyond UPS' capability. The newly emerging novel approaches may partially address issues that have long plagued researchers, such as low potency, poor cell permeability, on-/off-target toxicity, and delivery efficiency. Comprehensive considerations for the rational design of protein degraders and continuous efforts to seek effective solutions are imperative to advance these strategies into clinical medications.
Topics: Humans; Proteolysis; Drug Discovery; Permeability; Proteolysis Targeting Chimera; Research Personnel
PubMed: 36895136
DOI: 10.1080/17460441.2023.2187777 -
Nature Communications Sep 2022Conditional degron tags (CDTs) are a powerful tool for target validation that combines the kinetics and reversible action of pharmacological agents with the...
Conditional degron tags (CDTs) are a powerful tool for target validation that combines the kinetics and reversible action of pharmacological agents with the generalizability of genetic manipulation. However, successful design of a CDT fusion protein often requires a prolonged, ad hoc cycle of construct design, failure, and re-design. To address this limitation, we report here a system to rapidly compare the activity of five unique CDTs: AID/AID2, IKZF3d, dTAG, HaloTag, and SMASh. We demonstrate the utility of this system against 16 unique protein targets. We find that expression and degradation are highly dependent on the specific CDT, the construct design, and the target. None of the CDTs leads to efficient expression and/or degradation across all targets; however, our systematic approach enables the identification of at least one optimal CDT fusion for each target. To enable the adoption of CDT strategies more broadly, we have made these reagents, and a detailed protocol, available as a community resource.
Topics: Kinetics; Proteolysis
PubMed: 36127368
DOI: 10.1038/s41467-022-33246-4 -
Proceedings of the National Academy of... Oct 2023Gram-positive bacteria use SigI/RsgI-family sigma factor/anti-sigma factor pairs to sense and respond to cell wall defects and plant polysaccharides. In this signal...
Gram-positive bacteria use SigI/RsgI-family sigma factor/anti-sigma factor pairs to sense and respond to cell wall defects and plant polysaccharides. In this signal transduction pathway involves regulated intramembrane proteolysis (RIP) of the membrane-anchored anti-sigma factor RsgI. However, unlike most RIP signaling pathways, site-1 cleavage of RsgI on the extracytoplasmic side of the membrane is constitutive and the cleavage products remain stably associated, preventing intramembrane proteolysis. The regulated step in this pathway is their dissociation, which is hypothesized to involve mechanical force. Release of the ectodomain enables intramembrane cleavage by the RasP site-2 protease and activation of SigI. The constitutive site-1 protease has not been identified for any RsgI homolog. Here, we report that RsgI's extracytoplasmic domain has structural and functional similarities to eukaryotic SEA domains that undergo autoproteolysis and have been implicated in mechanotransduction. We show that site-1 proteolysis in and Clostridial RsgI family members is mediated by enzyme-independent autoproteolysis of these SEA-like domains. Importantly, the site of proteolysis enables retention of the ectodomain through an undisrupted β-sheet that spans the two cleavage products. Autoproteolysis can be abrogated by relief of conformational strain in the scissile loop, in a mechanism analogous to eukaryotic SEA domains. Collectively, our data support the model that RsgI-SigI signaling is mediated by mechanotransduction in a manner that has striking parallels with eukaryotic mechanotransducive signaling pathways.
Topics: Mechanotransduction, Cellular; Proteolysis; Bacillus subtilis; Cell Wall; Eukaryota
PubMed: 37756332
DOI: 10.1073/pnas.2310862120 -
Biomolecules Nov 2021The proteasome system is a large and complex molecular machinery responsible for the degradation of misfolded, damaged, and redundant cellular proteins. When proteasome... (Review)
Review
The proteasome system is a large and complex molecular machinery responsible for the degradation of misfolded, damaged, and redundant cellular proteins. When proteasome function is impaired, unwanted proteins accumulate, which can lead to several diseases including age-related and neurodegenerative diseases. Enhancing proteasome-mediated substrate degradation with small molecules may therefore be a valuable strategy for the treatment of various neurodegenerative diseases such as Parkinson's, Alzheimer's, and Huntington's diseases. In this review, we discuss the structure of proteasome and how proteasome's proteolytic activity is associated with aging and various neurodegenerative diseases. We also summarize various classes of compounds that are capable of enhancing, directly or indirectly, proteasome-mediated protein degradation.
Topics: Aging; Humans; Neurodegenerative Diseases; Proteasome Endopeptidase Complex; Proteasome Inhibitors; Protein Folding; Proteolysis; Small Molecule Libraries
PubMed: 34944433
DOI: 10.3390/biom11121789 -
The FEBS Journal May 2020Proteases play critical roles in virtually all biological processes, including proliferation, cell death and survival, protein turnover, and migration. However, when... (Review)
Review
Proteases play critical roles in virtually all biological processes, including proliferation, cell death and survival, protein turnover, and migration. However, when dysregulated, these enzymes contribute to the progression of multiple diseases, with cancer, neurodegenerative disorders, inflammation, and blood disorders being the most prominent examples. For a long time, disease-associated proteases have been used for the activation of various prodrugs due to their well-characterized catalytic activity and ability to selectively cleave only those substrates that strictly correspond with their active site architecture. To date, versatile peptide sequences that are cleaved by proteases in a site-specific manner have been utilized as bioactive linkers for the targeted delivery of multiple types of cargo, including fluorescent dyes, photosensitizers, cytotoxic drugs, antibiotics, and pro-antibodies. This platform is highly adaptive, as multiple protease-labile conjugates have already been developed, some of which are currently in clinical use for cancer treatment. In this review, recent advancements in the development of novel protease-cleavable linkers for selective drug delivery are described. Moreover, the current limitations regarding the selectivity of linkers are discussed, and the future perspectives that rely on the application of unnatural amino acids for the development of highly selective peptide linkers are also presented.
Topics: Catalysis; Catalytic Domain; Drug Delivery Systems; Humans; Peptide Hydrolases; Peptides; Prodrugs; Proteolysis
PubMed: 31991521
DOI: 10.1111/febs.15227 -
BioEssays : News and Reviews in... Jan 2015We propose for the first time to divide histone proteolysis into "histone degradation" and the epigenetically connoted "histone clipping". Our initial observation is... (Review)
Review
We propose for the first time to divide histone proteolysis into "histone degradation" and the epigenetically connoted "histone clipping". Our initial observation is that these two different classes are very hard to distinguish both experimentally and biologically, because they can both be mediated by the same enzymes. Since the first report decades ago, proteolysis has been found in a broad spectrum of eukaryotic organisms. However, the authors often not clearly distinguish or determine whether degradation or clipping was studied. Given the importance of histone modifications in epigenetic regulation we further elaborate on the different ways in which histone proteolysis could play a role in epigenetics. Finally, unanticipated histone proteolysis has probably left a mark on many studies of histones in the past. In conclusion, we emphasize the significance of reviving the study of histone proteolysis both from a biological and an experimental perspective. Also watch the Video Abstract.
Topics: Animals; Histones; Humans; Models, Biological; Proteolysis
PubMed: 25350939
DOI: 10.1002/bies.201400118