Small Molecule Enhancement of 20S Proteasome Activity Targets Intrinsically Disordered Proteins

Jones, Carl J.; Njomen, Evert; Sjögren, Benita; Dexheimer, Thomas S.; Tepe, Jetze J.

doi:10.1021/acschembio.7b00489

Cited by 76 publications

(113 citation statements)

References 56 publications

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“…29,30 For these studies, the disordered proteins α -syn (Figure 2C) and tau (Figure 2D) were mixed with the structured protein, GAPDH, and treated with the purified 20S proteasome in the presence of various concentrations of TCH-165 or bortezomib (BTZ, proteasome inhibitor as a negative control) 66 for 1 h. The mixture was analyzed for protein degradation by Western blotting. Panels C and D of Figure 2 clearly demonstrate that TCH-165 enhanced the degradation of both α -syn and tau over the vehicle control (Figure 2C,D; p < 0.01).…”

Section: Resultsmentioning

confidence: 99%

“…29 Briefly, 20S proteasome was diluted to 17 nM in reaction buffer. Test compounds or the vehicle (1 μ L of a 50× stock) was added to 44 μ L of 17 nM 20S and incubated at RT for 20 min.…”

Section: Methodsmentioning

confidence: 99%

“…29 Briefly, HEK293T cells were seeded at a density of 1 × 10 5 cells/mL in a 24-well plate overnight. DNA (1 μ g of GFPSpark-ODC plasmid) was mixed with 250 μ L of serum free DMEM medium.…”

Section: Methodsmentioning

confidence: 99%

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Small Molecule Modulation of Proteasome Assembly

et al. 2018

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The 20S proteasome is the main protease that directly targets intrinsically disordered proteins (IDPs) for proteolytic degradation. Mutations, oxidative stress, or aging can induce the buildup of IDPs resulting in incorrect signaling or aggregation, associated with the pathogenesis of many cancers and neurodegenerative diseases. Drugs that facilitate 20S-mediated proteolysis therefore have many potential therapeutic applications. We report herein the modulation of proteasome assembly by the small molecule TCH-165, resulting in an increase in 20S levels. The increase in the level of free 20S corresponds to enhanced proteolysis of IDPs, including α-synuclein, tau, ornithine decarboxylase, and c-Fos, but not structured proteins. Clearance of ubiquitinated protein was largely maintained by single capped proteasome complexes (19S–20S), but accumulation occurs when all 19S capped proteasome complexes are depleted. This study illustrates the first example of a small molecule capable of targeting disordered proteins for degradation by regulating the dynamic equilibrium between different proteasome complexes.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Small Molecule Modulation of Proteasome Assembly

et al. 2018

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“…However, reports on pharmacological augmentation are limited to in vitro and cell culture studies. [16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

New Peptide-Based Pharmacophore Activates 20S Proteasome

et al. 2020

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The proteasome is a pivotal element of controlled proteolysis, responsible for the catabolic arm of proteostasis. By inducing apoptosis, small molecule inhibitors of proteasome peptidolytic activities are successfully utilized in treatment of blood cancers. However, the clinical potential of proteasome activation remains relatively unexplored. In this work, we introduce short TAT peptides derived from HIV-1 Tat protein and modified with synthetic turn-stabilizing residues as proteasome agonists. Molecular docking and biochemical studies point to the α1/α2 pocket of the core proteasome α ring as the binding site of TAT peptides. We postulate that the TATs’ pharmacophore consists of an N-terminal basic pocket-docking “activation anchor” connected via a β turn inducer to a C-terminal “specificity clamp” that binds on the proteasome α surface. By allosteric effects—including destabilization of the proteasomal gate—the compounds substantially augment activity of the core proteasome in vitro. Significantly, this activation is preserved in the lysates of cultured cells treated with the compounds. We propose that the proteasome-stimulating TAT pharmacophore provides an attractive lead for future clinical use.

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“…It has long been hypothesized, for example, that increasing proteasome activity could combat premature aging or neurological diseases. There are several examples of molecules that can stimulate the activity of the proteasome . More recently, it has been proposed that proteasome inhibitors might aid in treating autoimmune diseases .…”

Section: Discussionmentioning

confidence: 99%

Small‐Molecule Inhibitors of the Proteasome's Regulatory Particle

2019

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Cells need to synthesize and degrade proteins consistently. Maintaining a balanced level of protein in the cell requires a carefully controlled system and significant energy. Degradation of unwanted or damaged proteins into smaller peptide units can be accomplished by the proteasome. The proteasome is composed of two main subunits. The first is the core particle (20S CP), and within this core particle are three types of threonine proteases. The second is the regulatory complex (19S RP), which has a myriad of activities including recognizing proteins marked for degradation and shuttling the protein into the 20S CP to be degraded. Small‐molecule inhibitors of the 20S CP have been developed and are exceptional treatments for multiple myeloma (MM). 20S CP inhibitors disrupt the protein balance, leading to cellular stress and eventually to cell death. Unfortunately, the 20S CP inhibitors currently available have dose‐limiting off‐target effects and resistance can be acquired rapidly. Herein, we discuss small molecules that have been discovered to interact with the 19S RP subunit or with a protein closely associated with 19S RP activity. These molecules still elicit their toxicity by preventing the proteasome from degrading proteins, but do so through different mechanisms of action.

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Small Molecule Enhancement of 20S Proteasome Activity Targets Intrinsically Disordered Proteins

Cited by 76 publications

References 56 publications

Small Molecule Modulation of Proteasome Assembly

Small Molecule Modulation of Proteasome Assembly

New Peptide-Based Pharmacophore Activates 20S Proteasome

Small‐Molecule Inhibitors of the Proteasome's Regulatory Particle

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