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Nature Reviews. Drug Discovery Mar 2022Targeted protein degradation (TPD) is an emerging therapeutic modality with the potential to tackle disease-causing proteins that have historically been highly... (Review)
Review
Targeted protein degradation (TPD) is an emerging therapeutic modality with the potential to tackle disease-causing proteins that have historically been highly challenging to target with conventional small molecules. In the 20 years since the concept of a proteolysis-targeting chimera (PROTAC) molecule harnessing the ubiquitin-proteasome system to degrade a target protein was reported, TPD has moved from academia to industry, where numerous companies have disclosed programmes in preclinical and early clinical development. With clinical proof-of-concept for PROTAC molecules against two well-established cancer targets provided in 2020, the field is poised to pursue targets that were previously considered 'undruggable'. In this Review, we summarize the first two decades of PROTAC discovery and assess the current landscape, with a focus on industry activity. We then discuss key areas for the future of TPD, including establishing the target classes for which TPD is most suitable, expanding the use of ubiquitin ligases to enable precision medicine and extending the modality beyond oncology.
Topics: Humans; Proteasome Endopeptidase Complex; Proteins; Proteolysis
PubMed: 35042991
DOI: 10.1038/s41573-021-00371-6 -
Signal Transduction and Targeted Therapy Apr 2022Traditional drug discovery mainly focuses on direct regulation of protein activity. The development and application of protein activity modulators, particularly... (Review)
Review
Traditional drug discovery mainly focuses on direct regulation of protein activity. The development and application of protein activity modulators, particularly inhibitors, has been the mainstream in drug development. In recent years, PROteolysis TArgeting Chimeras (PROTAC) technology has emerged as one of the most promising approaches to remove specific disease-associated proteins by exploiting cells' own destruction machinery. In addition to PROTAC, many different targeted protein degradation (TPD) strategies including, but not limited to, molecular glue, Lysosome-Targeting Chimaera (LYTAC), and Antibody-based PROTAC (AbTAC), are emerging. These technologies have not only greatly expanded the scope of TPD, but also provided fresh insights into drug discovery. Here, we summarize recent advances of major TPD technologies, discuss their potential applications, and hope to provide a prime for both biologists and chemists who are interested in this vibrant field.
Topics: Drug Discovery; Proteins; Proteolysis
PubMed: 35379777
DOI: 10.1038/s41392-022-00966-4 -
Journal of Hematology & Oncology May 2020Proteolysis-targeting chimera (PROTAC) has been developed to be a useful technology for targeted protein degradation. A bifunctional PROTAC molecule consists of a ligand... (Review)
Review
Proteolysis-targeting chimera (PROTAC) has been developed to be a useful technology for targeted protein degradation. A bifunctional PROTAC molecule consists of a ligand (mostly small-molecule inhibitor) of the protein of interest (POI) and a covalently linked ligand of an E3 ubiquitin ligase (E3). Upon binding to the POI, the PROTAC can recruit E3 for POI ubiquitination, which is subjected to proteasome-mediated degradation. PROTAC complements nucleic acid-based gene knockdown/out technologies for targeted protein reduction and could mimic pharmacological protein inhibition. To date, PROTACs targeting ~ 50 proteins, many of which are clinically validated drug targets, have been successfully developed with several in clinical trials for cancer therapy. This article reviews PROTAC-mediated degradation of critical oncoproteins in cancer, particularly those in hematological malignancies. Chemical structures, cellular and in vivo activities, pharmacokinetics, and pharmacodynamics of these PROTACs are summarized. In addition, potential advantages, challenges, and perspectives of PROTAC technology in cancer therapy are discussed.
Topics: Animals; Antineoplastic Agents; Drug Discovery; Humans; Ligands; Molecular Targeted Therapy; Neoplasms; Proteolysis; Ubiquitination
PubMed: 32404196
DOI: 10.1186/s13045-020-00885-3 -
Nature Communications Jan 2023Post-translational modifications (PTMs) can occur on specific amino acids localized within regulatory domains of target proteins, which control a protein's stability.... (Review)
Review
Post-translational modifications (PTMs) can occur on specific amino acids localized within regulatory domains of target proteins, which control a protein's stability. These regions, called degrons, are often controlled by PTMs, which act as signals to expedite protein degradation (PTM-activated degrons) or to forestall degradation and stabilize a protein (PTM-inactivated degrons). We summarize current knowledge of the regulation of protein stability by various PTMs. We aim to display the variety and breadth of known mechanisms of regulation as well as highlight common themes in PTM-regulated degrons to enhance potential for identifying novel drug targets where druggable targets are currently lacking.
Topics: Protein Processing, Post-Translational; Proteins; Proteolysis; Amino Acids; Protein Stability
PubMed: 36639369
DOI: 10.1038/s41467-023-35795-8 -
International Journal of Molecular... Apr 2018Ever since the discovery of ubiquitin in 1975[...].
Ever since the discovery of ubiquitin in 1975[...].
Topics: Animals; Drug Discovery; Humans; Molecular Targeted Therapy; Proteolysis; Signal Transduction; Ubiquitin; Ubiquitination
PubMed: 29617326
DOI: 10.3390/ijms19041080 -
Chemical Society Reviews Oct 2022Targeted protein degradation (TPD) provides unprecedented opportunities for drug discovery. While the proteolysis-targeting chimera (PROTAC) technology has already... (Review)
Review
Targeted protein degradation (TPD) provides unprecedented opportunities for drug discovery. While the proteolysis-targeting chimera (PROTAC) technology has already entered clinical trials and changed the landscape of small-molecule drugs, new degrader technologies harnessing alternative degradation machineries, especially lysosomal pathways, have emerged and broadened the spectrum of degradable targets. We have recently proposed the concept of autophagy-tethering compounds (ATTECs) that hijack the autophagy protein microtubule-associated protein 1A/1B light chain 3 (LC3) for targeted degradation. Other groups also reported degrader technologies engaging lysosomal pathways through different mechanisms including AUTACs, AUTOTACs, LYTACs and MoDE-As. In this review, we analyse and discuss ATTECs along with other lysosomal-relevant degrader technologies. Finally, we will briefly summarize the current status of these degrader technologies and envision possible future studies.
Topics: Proteolysis; Drug Discovery; Proteins; Autophagy; Lysosomes
PubMed: 36218065
DOI: 10.1039/d2cs00624c -
Cell Jun 2022Hijacking the cellular protein degradation system offers unique opportunities for drug discovery, as exemplified by proteolysis-targeting chimeras. Despite their great...
Hijacking the cellular protein degradation system offers unique opportunities for drug discovery, as exemplified by proteolysis-targeting chimeras. Despite their great promise for medical chemistry, so far, it has not been possible to reprogram the bacterial degradation machinery to interfere with microbial infections. Here, we develop small-molecule degraders, so-called BacPROTACs, that bind to the substrate receptor of the ClpC:ClpP protease, priming neo-substrates for degradation. In addition to their targeting function, BacPROTACs activate ClpC, transforming the resting unfoldase into its functional state. The induced higher-order oligomer was visualized by cryo-EM analysis, providing a structural snapshot of activated ClpC unfolding a protein substrate. Finally, drug susceptibility and degradation assays performed in mycobacteria demonstrate in vivo activity of BacPROTACs, allowing selective targeting of endogenous proteins via fusion to an established degron. In addition to guiding antibiotic discovery, the BacPROTAC technology presents a versatile research tool enabling the inducible degradation of bacterial proteins.
Topics: Bacteria; Bacterial Proteins; Molecular Chaperones; Proteolysis
PubMed: 35662409
DOI: 10.1016/j.cell.2022.05.009 -
Trends in Cell Biology Jan 2022Aberrancy in cell cycle progression is one of the fundamental mechanisms underlying tumorigenesis, making regulators of the cell cycle machinery rational anticancer... (Review)
Review
Aberrancy in cell cycle progression is one of the fundamental mechanisms underlying tumorigenesis, making regulators of the cell cycle machinery rational anticancer therapeutic targets. A growing body of evidence indicates that the cell cycle regulatory pathway integrates into other hallmarks of cancer, including metabolism remodeling and immune escape. Thus, therapies against cell cycle machinery components can not only repress the division of cancer cells, but also reverse cancer metabolism and restore cancer immune surveillance. Besides the ongoing effects on the development of small molecule inhibitors (SMIs) of the cell cycle machinery, proteolysis targeting chimeras (PROTACs) have recently been used to target these oncogenic proteins related to cell cycle progression. Here, we discuss the rationale of cell cycle targeting therapies, particularly PROTACs, to more efficiently retard tumorigenesis.
Topics: Carcinogenesis; Cell Cycle; Cell Transformation, Neoplastic; Humans; Neoplasms; Proteolysis
PubMed: 34304958
DOI: 10.1016/j.tcb.2021.07.001 -
Proceedings of the National Academy of... Jan 2019This perspective is partly review and partly proposal. N-degrons and C-degrons are degradation signals whose main determinants are, respectively, the N-terminal and... (Review)
Review
This perspective is partly review and partly proposal. N-degrons and C-degrons are degradation signals whose main determinants are, respectively, the N-terminal and C-terminal residues of cellular proteins. N-degrons and C-degrons include, to varying extents, adjoining sequence motifs, and also internal lysine residues that function as polyubiquitylation sites. Discovered in 1986, N-degrons were the first degradation signals in short-lived proteins. A particularly large set of C-degrons was discovered in 2018. We describe multifunctional proteolytic systems that target N-degrons and C-degrons. We also propose to denote these systems as "N-degron pathways" and "C-degron pathways." The former notation replaces the earlier name "N-end rule pathways." The term "N-end rule" was introduced 33 years ago, when only some N-terminal residues were thought to be destabilizing. However, studies over the last three decades have shown that all 20 amino acids of the genetic code can act, in cognate sequence contexts, as destabilizing N-terminal residues. Advantages of the proposed terms include their brevity and semantic uniformity for N-degrons and C-degrons. In addition to being topologically analogous, N-degrons and C-degrons are related functionally. A proteolytic cleavage of a subunit in a multisubunit complex can create, at the same time, an N-degron (in a C-terminal fragment) and a spatially adjacent C-degron (in an N-terminal fragment). Consequently, both fragments of a subunit can be selectively destroyed through attacks by the N-degron and C-degron pathways.
Topics: Amino Acid Motifs; Amino Acid Sequence; Animals; Humans; Protein Domains; Proteolysis
PubMed: 30622213
DOI: 10.1073/pnas.1816596116 -
Molecular Cell Dec 2019Protein silencing represents an essential tool in biomedical research. Targeted protein degradation (TPD) strategies exemplified by PROTACs are rapidly emerging as...
Protein silencing represents an essential tool in biomedical research. Targeted protein degradation (TPD) strategies exemplified by PROTACs are rapidly emerging as modalities in drug discovery. However, the scope of current TPD techniques is limited because many intracellular materials are not substrates of proteasomal clearance. Here, we described a novel targeted-clearance strategy (autophagy-targeting chimera [AUTAC]) that contains a degradation tag (guanine derivatives) and a warhead to provide target specificity. As expected from the substrate scope of autophagy, AUTAC degraded fragmented mitochondria as well as proteins. Mitochondria-targeted AUTAC accelerated both the removal of dysfunctional fragmented mitochondria and the biogenesis of functionally normal mitochondria in patient-derived fibroblast cells. Cytoprotective effects against acute mitochondrial injuries were also seen. Canonical autophagy is viewed as a nonselective bulk decomposition system, and none of the available autophagy-inducing agents exhibit useful cargo selectivity. With its target specificity, AUTAC provides a new modality for research on autophagy-based drugs.
Topics: Autophagy; Autophagy-Related Proteins; Cell Line; Guanine; Humans; Mitochondria; Mitophagy; Protein Engineering; Protein Kinases; Protein Stability; Proteolysis
PubMed: 31606272
DOI: 10.1016/j.molcel.2019.09.009