Project description:In the 1950s the drug thalidomide administered as a sedative to pregnant women led ot the birth of thousands of children with multiple defects. Despite its teratogenicity, thalidomide and ist IMiD derivatives recently emerged as effective treatments for multiple myeloma and 5q-dysplasia. IMiDs target the CUL4-RBX1-DDB1-CRBN (CRL4(CRBN)) ubiquitin ligase. Through an unbiased screen we identify the homeobox trranscription factor MEIS2 as an endogenous substrate of CRL4(CRBN). By definition, a specific target of CRL4(CRBN) is expected to have a very low intensity on negative control arrays (E1_E2), (E1_CRBN), (E1_E2_Cdt2), (E1_E2_Cdt2_revlimid), (E1_E2_Cdt2_CSN) or with CRL4(CRBN) in presence of inhibitor (E1_E2_CRBN_revlimid) and high intensity on arrays with CRL4(CRBN) (E1_E2_CRBN) or CRL4(CRBN) in presence of CSN (E1_E2_CRBN_CSN) Accordingly 16 protein microarrays were subjected to in vitro ubiquitylation using the following enzyme combinations: 3x Uba1+UbcH5a; 2x Uba1+UbcH5a+CRL4(DDB2); 3x Uba1+UbcH5a+CRL4(CRBN); 2x Uba1+UbcH5a+CRL4(CRBN)+lenalidomide; 2x Uba1+UbcH5a+CRL4(CRBN)+CSN; 2x Uba1+UbcH5a+CRL4(Cdt2); 1x Uba1+UbcH5a+CRL4(Cdt2)+CSN; 1x Uba1+UbcH5a+CRL4(Cdt2)+lenalidomide
Project description:In the 1950s the drug thalidomide administered as a sedative to pregnant women led ot the birth of thousands of children with multiple defects. Despite its teratogenicity, thalidomide and ist IMiD derivatives recently emerged as effective treatments for multiple myeloma and 5q-dysplasia. IMiDs target the CUL4-RBX1-DDB1-CRBN (CRL4(CRBN)) ubiquitin ligase. Through an unbiased screen we identify the homeobox trranscription factor MEIS2 as an endogenous substrate of CRL4(CRBN).
Project description:We present a first-in-class GSPT1-selective CELMoD, CC-90009, which is currently in a phase 1 clinical trial for the treatment of relapsed or refractory (R/R) AML (CC-90009-AML-001; NCT02848001). Biochemical, structural and molecular characterization supports that CC-90009 coopts the CUL4-DDB1-CRBN-RBX1 (CRL4-CRBN) E3 ubiquitin ligase complex to selectively target GSPT1 for ubiquitination and proteasomal degradation, culminating in rapid induction of apoptosis and growth inhibition in AML cell lines and patient leukemic blasts. Knockout of ILF2/ILF3 decreased the production of full-length CRBN transcript via modulating CRBN mRNA alternative splicing, leading to significant downregulation of cereblon expression and hence diminished response to CC-90009.
Project description:Ubiquitin-mediated proteolysis play a significant role in various biological processes including transcription, DNA repair and cell cycle progression. The identification of Set8 and Set8b (a splice isoform) histone H4K20 methyl transferase as a substrate for the cullin-based ubiquitin ligase (CRL4-Cdt2) demonstrate that this pathway plays a significant role in promoting cell cycle progression, specifically promoting G2 progression. This study investigate the effect of failure to degrade Set8 in S-phase of the cell cycle via CRL4-Cdt2 on gene expression. We used microarrays to detail the effect of the expression of stable form of Set8b H4K20 mono-methyl transferase (Set8b_deltaPIP2) on gene expression Human osteosarcoma-derived human cells were transduced with retroviruses encoding either wt-Set8b or a mutant of Setb8 which is resistant to degradation via CRL4-Cdt2 ubiquitin ligase complex (Set8b_deltaPIP2) or with an a control pMSCV empty virus. 5 days after transduction, cells were harvested and the RNA was extracted by Trizol (Invitrogen) and hybridized to the affymetrix chips array.
Project description:Cereblon (CRBN) is a ubiquitin ligase widely harnessed for targeted protein degradation. We report the discovery of a molecular glue that drives CRBN homo-dimerization and subsequent fast, potent, and selective CRBN degradation by the ubiquitin proteasome system. The structure of the complex reveals a unique mechanism whereby two molecular glues assemble into a helix-like structure and drive ternary complex formation by mimicking a protein degron in trans.
Project description:Cereblon (CRBN) is a ubiquitin ligase widely harnessed for targeted protein degradation. We report the discovery of a molecular glue that drives CRBN homo-dimerization and subsequent fast, potent, and selective CRBN degradation by the ubiquitin proteasome system. The structure of the complex reveals a unique mechanism whereby two molecular glues assemble into a helix-like structure and drive ternary complex formation by mimicking a protein degron in trans.
Project description:Cereblon (CRBN) is a ubiquitin ligase widely harnessed for targeted protein degradation. We report the discovery of a molecular glue that drives CRBN homo-dimerization and subsequent fast, potent, and selective CRBN degradation by the ubiquitin proteasome system. The structure of the complex reveals a unique mechanism whereby two molecular glues assemble into a helix-like structure and drive ternary complex formation by mimicking a protein degron in trans.
Project description:Cell cycle progression in mammals is modulated by two ubiquitin ligase complexes, CRL4 and SCF, which facilitate degradation of chromatin substrates involved in the regulation of DNA replication. One member of the CRL4 complex, RepID (DCAF14/PHIP), is a WD40-containing protein that selectively binds and activates a group of replication origins. We found that RepID recruits the CRL4 complex to chromatin prior to DNA synthesis, thus playing a crucial architectural role in the proper licensing of chromosomes for replication. In the absence of RepID, cells rely on the alternative ubiquitin ligase, SKP2-containing SCF, to progress through the cell cycle. RepID depletion markedly increases cellular sensitivity to SKP2 inhibitors, which triggered massive genome re-replication. Both RepID and SKP2 interact with distinct, non-overlapping groups of replication origins, suggesting that selective interactions of replication origins with specific CRL components execute the DNA replication program and maintain genomic stability by preventing re-initiation of DNA replication.
Project description:Ubiquitin-mediated proteolysis play a significant role in various biological processes including transcription, DNA repair and cell cycle progression. The identification of Set8 and Set8b (a splice isoform) histone H4K20 methyl transferase as a substrate for the cullin-based ubiquitin ligase (CRL4-Cdt2) demonstrate that this pathway plays a significant role in promoting cell cycle progression, specifically promoting G2 progression. This study investigate the effect of failure to degrade Set8 in S-phase of the cell cycle via CRL4-Cdt2 on gene expression.
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.