Project description:Molecular profiling of cultured CD8+ T cells from mice and treated with either IL2, IL2/SIIKFEKL(TCR), IL2/IL4, or IL2/IL4/SIINFEKL(TCR)
Project description:Transcriptomic profiling of cultured CD8+ T cells from mice and treated with either IL2, IL2/SIINFEKL(TCR), IL2/IL4, or IL2/IL4/SIINFEKL(TCR)
Project description:To investigate the mechanism by which Cul5 regulates CD8+ T cell cytokine-dependent differentiation and TCR-dependent activation, we performed quantitative mass spectrometry (MS) by data-independent acquisition (DIA)-MS of total proteins in the Cul5 KO and NC primary CD8+ T cells in the following conditions: 1) Cytokine dependent expansion and differentiation (T0); 2) 8 hours cytokine withdraw prior to TCR stimulation (T8); and 3) 16 hours TCR stimulation post 8-hour cytokine withdraw (T16). Principal component analysis (PCA) and correlation analysis revealed that replicates in each condition clustered together while different conditions separated from each other, suggesting significant proteomic changes among different conditions of the same T cells as well as between Cul5 KO and NC T cells in each condition. Together with similar total protein quantities among all detected samples, DIA-MS analyses were of high quality. Additionally, the strong reductions of Cul5 abundances in the Cul5 KO cells from all three conditions compared to the NC cells confirms high KO efficiency. Of note, the proteomic analysis showed that the Cul5 protein level was significantly increased upon TCR stimulation post cytokine starvation in the NC cells, suggesting a potential negative feedback regulatory role of Cul5 in CD8+ T cell activation. Consistent with this idea, we observed more markedly upregulation of Cul5 expression upon of TCR stimulation of na•ve primary CD8+ cells. To identify Cul5 interacting proteins in CD8+ T cells, we overexpressed Cul5 with a C terminal HA-tag (Cul5-HA) in mouse primary CD8+ T cells by retroviral transduction. The cells were subjected to TCR stimulation for 12 hr, and Cul5-HA was immunoprecipitated by anti-HA, followed by DIA-MS analysis (co-IP-MS). Compared to the negative control samples (cells transduced with the empty vector), 65 proteins were enriched (p value <0.05 and fold change >1.5) in the anti-HA IP samples. Altogether, we report that Cul5 KO alters CD8+ T cell proteome and the Cul5 interactome.
Project description:To help advancing cancer immunotherapies, we developed a step-wise CRISPR knockout (KO) screening strategy under the selection of TGF-beta, and identified Cul5 as a core negative-feedback regulator of CD8+ T cell differentiation and persistence.
Project description:FBXW7 is and E3 ubiquitin ligase and is highly mutated in colorectal cancer. We used human colon organoids with engineered FBXW7 hotspot mutations to investigate novel targets of E3 ligase activity with a combined transcriptomic and proteomic approach uncovering the EGFR-MAPK pathway as highly regulated by the E3 ligase activity.
Project description:ChIP-Seq of three H3 Acetylation epitopes in cultured CD8+ T cells from mice and treated with either IL2, IL2/SIINFEKL(TCR), IL2/IL4, or IL2/IL4/SIINFEKL(TCR)
Project description:The Hace1 E3 ligase is a tumor suppressor in stressed cells. Through unknown mechanisms, Hace1 indirectly targets the cyclin D1 proto-oncogene for proteasomal degradation during nutrient depletion. We now show that Hace1 targets HIF1alpha for VHL-dependent degradation during hypoxia. To better understand these diverse actions we performed mass spectrometry to identify Hace1-interacting proteins. We show that Hace1 interacts with cullin-associated NEDD8-dissociated protein 1 (CAND1) under nutrient depletion and hypoxia. CAND1 binds cullins and prevents their entry into cullin ring E3 ligase (CRL) complexes, thus blocking CRL activity. Hace1 binding releases CUL1/2 from CAND1, facilitating assembly of CRL complexes to degrade cyclin D1 and HIF1alpha, respectively. These findings suggest a broad role for Hace1 in regulating tumor suppressive CRL E3 ligases. In this study, we used gene expression profiling to characterize how Hace1 overexpression affect the transcriptional response to hypoxic stress Using Affymetrix exon-level microarrays, we compared the expression profile of HEK293 cells overexpressing either Hace1 or MSCV vector alone, under hypoxia or normoxia
Project description:It has been recognized that BRCA1, in the form of the BRCA1/BARD1 heterodimer, acting as an ubiquitin E3 ligase offered a possible mechanism to explain its pleiotrophic nature of BRCA1 activity. Our observation that mice lacking BRCA1 enzymatic activity are viable apart from male sterility was unexpected. Our results suggest that the E3 ligase activity of BRCA1 is largely dispensable for normal development and is not essential for all BRCA1 functions. Thus, many of the known and unknown functions of BRCA1 are likely to be mediated independent of its ability to catalyze ubiquitination. The genome copy number patterns were studied on the mice tumors that lacks E3 ubiqitin ligase activity of BRCA1 and were compared to copy number profile of mice lacking p53 and both brca1 and p53. Array CGH was performed using Agilent mouse CGH microarray 244K kit. Genomic DNA isolated from tumor tissue and its corresponding mouse tail were labelled with two different dyes and hybridized simultaneously on to microarray slides to perform comparitive genomic hybridization.
Project description:The budding yeast E3 SUMO ligase Mms21, a component of the Smc5-6 complex, regulates sister chromatid cohesion, DNA replication, and DNA repair. We identify a role for Mms21 in ribosome biogenesis. The mms21RINGD mutant exhibits reduced rRNA production, nuclear accumulation of 60S and 40S ribosomal proteins, and elevated Gcn4 translation. Genes involved in ribosome biogenesis and translation are down-regulated in the mms21RINGD mutant. Examining gene expression profile of mms21RINGD mutant compared to wild-type by RNA Seq using Ilumina sequencing
Project description:It has been recognized that BRCA1, in the form of the BRCA1/BARD1 heterodimer, acting as an ubiquitin E3 ligase offered a possible mechanism to explain its pleiotrophic nature of BRCA1 activity. Our observation that mice lacking BRCA1 enzymatic activity are viable apart from male sterility was unexpected. Our results suggest that the E3 ligase activity of BRCA1 is largely dispensable for normal development and is not essential for all BRCA1 functions. Thus, many of the known and unknown functions of BRCA1 are likely to be mediated independent of its ability to catalyze ubiquitination. The genome copy number patterns were studied on the mice tumors that lacks E3 ubiqitin ligase activity of BRCA1 and were compared to copy number profile of mice lacking p53 and both brca1 and p53.