Elucidation of E3 Ubiquitin Ligase Specificity Through Proteome-wide Internal Degron Mapping
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PROVIDER: PRJNA1004303 | ENA |
REPOSITORIES: ENA
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Project description:The ubiquitin-proteasome system plays critical roles in biology by regulating protein degradation. Despite their importance, precise recognition specificity is known for few of the 600 E3s. Here we establish a two-pronged strategy for identifying and mapping critical residues of internal degrons on a genome scale in HEK-293T cells. We employ Global Protein Stability profiling combined with machine learning to identify 15,800 peptides likely to contain sequence-dependent degrons. We combine this with scanning mutagenesis to define critical residues for over 5,000 predicted degrons. Focusing on Cullin-RING ligase degrons, we generated mutational fingerprints for 219 degrons and developed DegronID, a computational algorithm enabling the clustering of degron peptides with similar motifs. CRISPR analysis enabled the discovery of E3-degron pairs of which we uncover 16 pairs that revealed extensive degron variability and structural determinants. We provide the visualization of this data on the public DegronID Data Browser as a resource for future exploration.
2023-09-21 | GSE240610 | GEO
Project description:The ubiquitin-proteasome system plays a critical role in biology by regulating protein degradation. Despite their importance, precise recognition specificity is known for a few of the 600 E3s. Here, we establish a two-pronged strategy for identifying and mapping critical residues of internal degrons on a proteome-scale in HEK-293T cells. We employ global protein stability profiling combined with machine learning to identify 15,800 peptides likely to contain sequence-dependent degrons. We combine this with scanning mutagenesis to define critical residues for over 5,000 predicted degrons. Focusing on Cullin-RING ligase degrons, we generated mutational fingerprints for 219 degrons and developed DegronID, a computational algorithm enabling the clustering of degron peptides with similar motifs. CRISPR analysis enabled the discovery of E3-degron pairs, of which we uncovered 16 pairs that revealed extensive degron variability and structural determinants. We provide the visualization of these data on the public DegronID data browser as a resource for future exploration.
| S-EPMC10594193 | biostudies-literature
Project description:The E3 ligase factor cereblon (CRBN) is a target of thalidomide and lenalidomide, which are therapeutic agents used in the treatment of hematopoietic malignancies and as ligands for targeted protein degradation. These agents are proposed to mimic a naturally occurring degron; however, the structural motif recognized by the thalidomide-binding domain of CRBN is unknown. Here, we report that C-terminal cyclic imides, post-translational modifications that arise from intramolecular cyclization of glutamine or asparagine residues, are degrons for CRBN. Dipeptides bearing the cyclic imide degron are substitutes for thalidomide when embedded within bifunctional small molecule degraders. Installation of the degron to the C-terminus of proteins induces CRBN-dependent ubiquitylation and degradation in vitro and in cells. C-Terminal cyclic imides are previously underappreciated post-translational modifications found throughout the human proteome that are endogenously recognized and removed by CRBN. The discovery of the cyclic imide degron defines a novel regulatory process controlled by these modifications, which may impact the development of therapeutic agents that engage CRBN.
2022-07-28 | PXD034248 | Pride
Project description:Primary and secondary hypertension are major risk factors for cardiovascular disease. Elevated secretion of aldosterone resulting from primary aldosteronism (PA) is a key driver of secondary hypertension. Here, we identify an unexpected role for the ubiquitin ligase Siah1 in adrenal gland development and PA. Siah1a-/- mice exhibit altered adrenal gland morphology, as reflected by dysregulated zonation of the glomerulosa, increased aldosterone levels and aldosterone target gene expression, and reduced plasma potassium levels. Genes involved in catecholamine biosynthesis and cAMP signaling are upregulated in the adrenal glands of Siah1a-/- mice, while genes related to retinoic acid signaling and cholesterol biosynthesis are downregulated. Loss of Siah1 leads to increased expression of PIAS1, an E3 SUMO-protein ligase implicated in the suppression of LXR. Notably, SIAH1 sequence variants which impaired SIAH1 ubiquitin ligase activity, resulting in elevated PIAS1 expression, were identified in patients with PA. The involvement of Siah1–PIAS1 in adrenal gland organization and function points to a possible new therapeutic target for hyperaldosteronism.
2018-05-01 | GSE102963 | GEO
Project description:The exposed N-terminal or C-terminal residues of proteins can act, in cognate sequence contexts, as degradation signals (degrons) that are targeted by specific E3 ubiquitin ligases for proteasome-dependent degradation by N-degron or C-degron pathways. Here, we discovered a distinct C-degron pathway, termed the Gln/C-degron pathway, in which the B30.2 domain of E3 ubiquitin ligase TRIM7 (TRIM7B30.2) mediates the recognition of proteins bearing a C-terminal glutamine. By determining crystal structures of TRIM7B30.2 in complexes with various peptides, we show that TRIM7B30.2 forms a positively charged binding pocket to engage the "U"-shaped Gln/C-degron. The four C-terminal residues of a substrate play an important role in C-degron recognition, with C-terminal glutamine as the principal determinant. In vitro biochemical and cellular experiments were used to further analyze the substrate specificity and selective degradation of the Gln/C-degron by TRIM7.
| S-EPMC9335266 | biostudies-literature
Project description:Current models imply that the FERM domain protein Merlin, encoded by the tumor suppressor NF2, inhibits mitogenic signaling at or near the plasma membrane. Here, we show that the closed, growth inhibitory form of Merlin accumulates in the nucleus, binds to the E3 ubiquitin ligase CRL4DCAF1, and suppresses its activity. Depletion of DCAF1 blocks the promitogenic effect of inactivation of Merlin. Conversely, enforced expression of a Merlin-insensitive mutant of DCAF1 counteracts the antimitogenic effect of Merlin. Re-expression of Merlin and silencing of DCAF1 induce a similar, tumor-suppressive program of gene expression. Tumor-derived mutations invariably disrupt Merlinâs ability to interact with or inhibit CRL4DCAF1. Finally, depletion of DCAF1 inhibits the hyperproliferation of Schwannoma cells from NF2 patients and suppresses the oncogenic potential of Merlin-deficient tumor cell lines. We propose that Merlin suppresses tumorigenesis by translocating to the nucleus to inhibit CRL4DCAF1. To examine if Merlin controls gene expression through inhibition of CRL4DCAF1, and define the general function of this ligase, we compared the gene expression program activated by expression of Merlin or by depletion of DCAF1 in Merlin-null FC-1801 mouse Schwannoma cells
2010-03-09 | E-GEOD-19305 | biostudies-arrayexpress
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:Auxin critically regulates nearly every aspect of plant growth and development. Auxin-driven transcriptional responses are mediated through the AUXIN RESPONSE FACTOR (ARF) family of transcription factors. Although ARF protein stability is regulated via the 26S proteasome, molecular mechanisms underlying ARF stability and turnover are unknown. Here, we report the identification and functional characterization of an F-Box E3 ubiquitin ligase, which we have named AUXIN RESPONSE FACTOR F-BOX1 (AFF1). AFF1 directly interacts with ARF19 and regulates its accumulation. Mutants defective in AFF1 display ARF19 protein hyperaccumulation, mild auxin resistance, and developmental defects. Together, our data suggest a new mechanism, namely control of ARF protein stability, in regulating auxin responsiveness.
2022-06-09 | GSE172353 | GEO
Project description:E3 ligase recruitment of proteins containing terminal destabilizing motifs (degrons) is emerging as a major form of regulation. How those E3s discriminate bona fide substrates from other proteins with terminal degron-like sequences remains unclear. Here, we report that human KLHDC2, a CRL2 substrate receptor targeting C-terminal Gly-Gly degrons, is regulated through interconversion between two assemblies. In the self-inactivated homotetramer, KLHDC2's C-terminal Gly-Ser motif mimics a degron and engages the substrate-binding domain of another protomer. True substrates capture the monomeric CRL2KLHDC2, driving E3 activation by neddylation and subsequent substrate ubiquitylation. Non-substrates such as NEDD8 bind KLHDC2 with high affinity, but its slow on rate prevents productive association with CRL2KLHDC2. Without substrate, neddylated CRL2KLHDC2 assemblies are deactivated via distinct mechanisms: the monomer by deneddylation and the tetramer by auto-ubiquitylation. Thus, substrate specificity is amplified by KLHDC2 self-assembly acting like a molecular timer, where only bona fide substrates may bind before E3 ligase inactivation.
| S-EPMC10080726 | biostudies-literature
Project description:The N-degron pathway relates the half-life of a protein to its amino terminal (Nt) residue. Following cleavage of proteins by endopeptidases, new N-t amino acids are revealed and can be recognised by different E3 ligase enzymes that target the substrate proteins for degradation via the proteasome. Studies with artificial proteins have shown that PRT1 is an Arabidopsis thaliana E3 ligase with specificity for aromatic N-termini (phenylalanine, tyrosine, tryptophan), but very little is known about its physiological roles and endogenous substrates. To gain insight into the impact of PRT1 on the proteome, we conducted a quantitative proteomic analysis, comparing leaf proteins from the prt1-1 loss of function mutant with those from wild type plants.
2020-01-09 | PXD014238 | Pride