Project description:To further understanding the function of cullin 3 during inflammation in macrophages, we have employed mouse bone marrow derived macrophages microarray expression profiling to identify the gens that involve in regulationg inflammatory respones upon LPS challenge. Mouse BMM were stimulated with LPS for 6 hours and RNA was extracted for microarray. Ogt was indentified by comparison between wildtype and Cullin 3 knockout BMM.
Project description:DNA topoisomerase 1 (Top1) inhibitors are mainstays of anticancer therapy. These drugs trap Top1 on DNA, stabilizing the Top1-cleavage complex (Top1-cc). The accumulation of Top1-ccs perturbs DNA replication fork progression, leading to DNA breaks and cell death. By analyzing the genomic occupancy and activity of Top1, we show that cells adapt to treatment with multiple doses of Top1 inhibitor by promoting the degradation of Top1-ccs, allowing cells to better tolerate subsequent doses of Top1 inhibitor. The E3-RING Cullin 3 Ligase in complex with the BTBD1 and BTBD2 adaptor proteins promote Top1-cc ubiquitination and subsequent proteasomal degradation. NEDDylation of Cullin 3 activates this pathway and inhibition of protein NEDDylation or depletion of Cullin 3 sensitizes cancer cells to Top1 inhibitors. Collectively, our data identify a novel NEDD8-Cullin 3 pathway involved in the adaptive response to Top1 inhibitors, which can be targeted to improve the efficacy of Top1 drugs in cancer therapy.
Project description:Ubiquitin and ubiquitin-like proteins (UBLs) are directed to targets by cascades of E1, E2, and E3 enzymes. The largest ubiquitin E3 subclass consists of cullin-RING ligases (CRLs), which contain one each of several cullins (CUL1, -2, -3, -4, or -5) and RING proteins (RBX1 or -2). CRLs are activated by ligation of the UBL NEDD8 to a conserved cullin lysine. How is cullin NEDD8ylation specificity established? Here we report that, like UBE2M (also known as UBC12), the previously uncharacterized E2 UBE2F is a NEDD8-conjugating enzyme in vitro and in vivo. Biochemical and structural analyses indicate how plasticity of hydrophobic E1-E2 interactions and E1 conformational flexibility allow one E1 to charge multiple E2s. The E2s have distinct functions, with UBE2M/RBX1 and UBE2F/RBX2 displaying different target cullin specificities. Together, these studies reveal the molecular basis for and functional importance of hierarchical expansion of the NEDD8 conjugation system in establishing selective CRL activation. Mol Cell 33:483-495, 2009. Keywords: Comparison of gene expression profiles Ube2m and Ube2f are E2 enzymes that direct protein modification by NEDD8. Here we explore the specific functions of Ube2f and Ube2m by comparing gene expression profiles following knockdown of their function in NIH 3T3 cells. We used microarrays to detail the global programme of gene expression changes following knockdown of Ube2m and Ube2f in NIH 3T3 cells. NIH 3T3 cells were transduced with retroviral constructs containing shRNA directed against Ube2m or Ube2f. Three replicates of each condition were analyzed.