Targeting REGγ proteasome to facilitate target protein degradation
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo Sapiens
SUBMITTER: 
Lei Li
PROVIDER: PXD048952 | iProX | Sat Jan 27 00:00:00 GMT 2024
REPOSITORIES: iProX
Similar Datasets
Project description:Nuclear hormone receptors (NRs) are ligand-binding transcription factors that are widely targeted therapeutically. Hormone binding triggers NR activation and their subsequent proteasomal degradation through unknown ligand-dependent ubiquitin ligase machinery. NR degradation is therapeutically relevant. Efficacy of all-trans-retinoic acid (ATRA) for the treatment of acute promyelocytic leukemia requires degradation of the oncogenic fusion between the Promyelocytic Leukemia Protein (PML) with the Retinoic Acid Receptor Alpha (RARA). Here we use CRISPR-based screens to identify the HECT E3 ubiquitin ligase UBR5 as a ligase for PML-RARA and RARA and observe an agonist-dependent association between RARA and UBR5, which occurs directly on chromatin to regulate transcription. We present the cryo-EM structure of full-length human UBR5 and identify a Leu-X-X-Leu-Leu (LxxLL) binding motif that associates with a conserved degron in RARA. A high-resolution crystal structure of the RARA ligand binding domain in complex with this LxxLL motif shows how UBR5 binding is mutually exclusive with nuclear co-activator engagement. We demonstrate that UBR5 utilizes this conserved degron to additionally regulate hormone dependent protein stability for the glucocorticoid, progesterone, and vitamin D receptors. Our work establishes UBR5-driven NR degradation as an integral regulator of transcriptional signaling by nuclear hormones.
2023-07-20 | PXD041749 | Pride
Project description:Nuclear hormone receptors (NRs) are ligand-binding transcription factors that are widely targeted therapeutically. Hormone binding triggers NR activation and their subsequent proteasomal degradation through unknown ligand-dependent ubiquitin ligase machinery. NR degradation is therapeutically relevant. Efficacy of all-trans-retinoic acid (ATRA) for the treatment of acute promyelocytic leukemia requires degradation of the oncogenic fusion between the Promyelocytic Leukemia Protein (PML) with the Retinoic Acid Receptor Alpha (RARA). Here we use CRISPR-based screens to identify the HECT E3 ubiquitin ligase UBR5 as a ligase for PML-RARA and RARA and observe an agonist-dependent association between RARA and UBR5, which occurs directly on chromatin to regulate transcription. We present the cryo-EM structure of full-length human UBR5 and identify a Leu-X-X-Leu-Leu (LxxLL) binding motif that associates with a conserved degron in RARA. A high-resolution crystal structure of the RARA ligand binding domain in complex with this LxxLL motif shows how UBR5 binding is mutually exclusive with nuclear co-activator engagement. We demonstrate that UBR5 utilizes this conserved degron to additionally regulate hormone dependent protein stability for the glucocorticoid, progesterone, and vitamin D receptors. Our work establishes UBR5-driven NR degradation as an integral regulator of transcriptional signaling by nuclear hormones.
2023-07-20 | PXD040953 | Pride
Project description:Various stressors such as viral infection lead to the suppression of cap-dependent translation and the activation of the integrated stress response (ISR), since the stress-induced phosphorylated eukaryotic translation initiation factor 2 [eIF2(αP)] tightly binds to eIF2B to prevent it from exchanging guanine nucleotide molecules on its substrate, unphosphorylated eIF2. Sandfly fever Sicilian virus (SFSV) evades this cap-dependent translation suppression through the interaction between its nonstructural protein NSs and host eIF2B. However, its precise mechanism has remained unclear. Here, our cryo-electron microscopy (cryo-EM) analysis revealed that SFSV NSs binds to the α-subunit of eIF2B in a competitive manner with eIF2(αP). Together with SFSV NSs, eIF2B retains nucleotide exchange activity even in the presence of eIF2(αP), in line with the cryo-EM structures of the eIF2B•SFSV NSs•unphosphorylated eIF2 complex. A genome-wide ribosome profiling analysis clarified that SFSV NSs expressed in cultured human cells attenuates the ISR triggered by thapsigargin, an endoplasmic reticulum stress inducer. Furthermore, SFSV NSs introduced in rat hippocampal neurons and human induced-pluripotent stem (iPS) cell-derived motor neurons exhibited neuroprotective effects against the ISR-inducing stress. Since ISR inhibition is beneficial in various neurological disease models, SFSV NSs is promising as a therapeutic ISR inhibitor.
2021-11-11 | GSE174764 | GEO
Project description:Ribosome-associated quality control (RQC) represents a rescue pathway in eukaryotic cells triggered upon translational stalling. Collided ribosomes are recognized for subsequent dissociation followed by degradation of nascent peptides. However, endogenous RQC-inducing sequences and the mechanism underlying the ubiquitin-dependent ribosome dissociation remain poorly understood. Here, we identified the SDD1 mRNA from S. cerevisiae as an endogenous RQC substrate and reveal its mRNA and nascent peptide dependent stalling mechanism by mutational and cryo-EM analyses. In vitro translation of SDD1 mRNA enabled the reconstitution of Hel2-dependent poly-ubiquitination of collided di- and preferentially tri-ribosomes. Distinct trisome architecture was visualized by cryo-EM and provides the structural basis for more efficient recognition by Hel2 over disomes. Subsequently, the Slh1 helicase subunit of the RQC trigger (RQT) complex preferentially dissociates the first stalled poly-ubiquitinated ribosome in an ATP-dependent manner. Together, these findings provide fundamental mechanistic insights into RQC and its physiological role in maintaining cellular protein homeostasis.
2020-01-27 | GSE131214 | GEO
Project description:Selective protein degradation typically involves substrate recognition via short linear motifs known as degrons. Various degrons can be found at protein termini from bacteria to mammals. While N-degrons have been extensively studied, our understanding of C-degrons is still limited. Towards a comprehensive understanding of eukaryotic C-degron pathways, we performed an unbiased survey of C-degrons in budding yeast. We identified over 5000 potential C-degrons by stability profiling of random peptide libraries and of the yeast C-terminome. Combining machine learning, high-throughput mutagenesis and genetic screens revealed that the SCF ubiquitin ligase targets ~40% of degrons using a single F-box substrate receptor Das1. Although sequence-specific, Das1 is highly promiscuous, recognizing a variety of C-degron motifs. By screening for full-length substrates, we implicate SCFDas1 in degradation of orphan protein complex subunits. Altogether, this work highlights the variety of C-degron pathways in eukaryotes and uncovers how an SCF/C-degron pathway of broad specificity contributes to proteostasis.
2023-11-01 | GSE246422 | GEO
Project description:Protein degradation, a major eukaryotic response to cellular signals, is subject to numerous layers of regulation. In yeast, the evolutionarily conserved GID E3 ligase mediates glucose-induced degradation of fructose-1,6-bisphosphatase (Fbp1) and other gluconeogenic enzymes. “GID” is a collection of E3 ligase complexes; a core scaffold, RING-type catalytic core and supramolecular module along with interchangeable substrate receptors select targets for ubiquitylation. However, knowledge of additional cellular factors directly regulating GID-type E3s remains rudimentary. Here, we structurally and biochemically characterize Gid12 as a modulator of the GID E3 ligase complex targeting Fbp1. Our collection of cryo-EM reconstructions shows that Gid12 forms an extensive interface sealing the substrate receptor Gid4 onto the scaffold, and remodeling the degron binding site. Gid12 also sterically blocks a recruited Fbp1 from the ubiquitylation active sites. Our analysis of the role of Gid12 establishes principles that may more generally underlie E3 ligase regulation.
2022-05-29 | PXD028579 | Pride
Project description:Protein degradation, a major eukaryotic response to cellular signals, is subject to numerous layers of regulation. In yeast, the evolutionarily conserved GID E3 ligase mediates glucose-induced degradation of fructose-1,6-bisphosphatase (Fbp1) and other gluconeogenic enzymes. “GID” is a collection of E3 ligase complexes; a core scaffold, RING-type catalytic core and supramolecular module along with interchangeable substrate receptors select targets for ubiquitylation. However, knowledge of additional cellular factors directly regulating GID-type E3s remains rudimentary. Here, we structurally and biochemically characterize Gid12 as a modulator of the GID E3 ligase complex targeting Fbp1. Our collection of cryo-EM reconstructions shows that Gid12 forms an extensive interface sealing the substrate receptor Gid4 onto the scaffold, and remodeling the degron binding site. Gid12 also sterically blocks a recruited Fbp1 from the ubiquitylation active sites. Our analysis of the role of Gid12 establishes principles that may more generally underlie E3 ligase regulation.
2022-06-01 | PXD031713 | Pride
Project description:SPOP is known to bind to serine/theronine-rich degrons on substrate proteins. We identified two degron sequences within the PWWP and MYND domain of ZMYND11, a novel SPOP substrate, and investigated whether ZMYND11 may contribute to the transcriptional output of mutant SPOP in VCaP cancer cells. Hence, we performed over-expression of degron-deficient ZMYND11 and degron-deficient ZMYND11 with W294A mutation in VCaP cells. While WT ZMYND11 constructs can be robustly over-expressed at the mRNA level, only the degron-deficient variants yielded a robost increase in ZMYND11 protein expression. Degron mutant-induced transcriptional perturbations partially mimicked SPOP mutant-induced gene expression changes, suggesting that ZMYND11 is sufficient to recapitulate certain features of mutant SPOP.
2020-12-16 | E-MTAB-7173 | biostudies-arrayexpress
Project description:The CTLH complex is a multi-subunit ubiquitin ligase complex that recognizes substrates with Pro/N-degrons via substrate receptor GID4. Recently, focus has turned to the complex as a potential mediator of targeted protein degradation, but the role GID4-mediated substrate ubiquitylation and proteasomal degradation plays in humans has thus far remained unclear. Here, we report PFI-7, a potent, selective, and cell-active chemical probe that antagonizes Pro/N-degron binding to human GID4. Use of PFI-7 in proximity-dependent biotinylation enabled the identification of dozens of endogenous GID4-interacting proteins that bind via the GID4 substrate binding pocket, only a subset of which possess canonical Pro/N-degron sequences. GID4 interactors are enriched for nuclear and nucleolar proteins including RNA helicases. GID4 antagonism by PFI-7 altered protein levels of several proteins including RNA helicases as measured by label-free quantitative proteomics, defining proteins that are regulated by GID4 and the CTLH complex in humans. Interactions with GID4 via Pro/N-degron pathway were not sufficient to promote proteasomal degradation, however, demonstrating that CTLH interactors are regulated through a combination of degradative and non-degradative functions. The lack of degradation of GID4 interactors highlights potential challenges in utilizing GID4-recruiting bifunctional molecules for targeted protein degradation. Going forward, PFI-7 will be a valuable research tool for defining CTLH complex biology and honing targeted protein degradation strategies.
2024-05-16 | PXD038487 | Pride
Project description:p97 is an essential and abundant AAA+ ATPase that unfolds ubiquitylated substrates and is a central regulator of protein homeostasis. Here we report two cryo-EM structures of human p97 in complex with its p47 adaptor. One of the conformations is six-fold symmetric, corresponds to previously reported structures of p97, and lacks bound substrate. The other structure adopts a helical conformation, displays substrate running in an extended conformation through the pore of the p97 hexamer, and resembles structures reported for other AAA unfoldases. These findings support the model that p97 utilizes a “hand-over-hand” mechanism in which two residues of the substrate are translocated for hydrolysis of two ATPs, one in each of the two p97 AAA ATPase rings. Proteomics analysis supports the model that one p97 complex can bind multiple substrate adaptors or binding partners, and can process substrates with multiple types of ubiquitin modification
2022-05-16 | PXD033451 | Pride