ABSTRACT: HIS-SUMO2 expressing HeLa and U2OS cells were treated with ubiquitin E1 inhibitor TAK243 with or without the presence of cycloheximide. Subsequently, HIS-SUMO2 conjugates were purified and analyzed by LC-MS/MS
Project description:Comprehensive list of SUMO targets from the nematode Caenorhabditis elegans. SUMO conjugates isolated from transgenic worms carrying 8His and GFP tagged SUMO. The constructs rescues the lethal knock-out of a single SUMO gene, smo-1. SUMO conjugates where isolated from heat shock, arsenite exposure, and UV treated SUMO-GFP worms as well as from control non treated animals. In parallel identical purification procedure was performed with non-transgenic worms and proteins identified with this control where excluded.
Project description:Small Ubiquitin-like Modifiers play critical roles in the DNA Damage Response (DDR). To increase our understanding of SUMOylation in the mammalian DDR, we employed a quantitative proteomics approach to identify dynamically regulated SUMO-2 conjugates and modification sites upon treatment with the DNA damaging agent MMS. We have uncovered a dynamic set of 20 upregulated and 33 downregulated SUMO-2 conjugates, and 755 SUMO-2 sites, of which 362 were dynamic in response to MMS. In contrast to yeast, where a response is centered on homologous recombination, we identified dynamically SUMOylated interaction networks of chromatin modifiers, transcription factors, DNA repair factors and nuclear body components. SUMOylated chromatin modifiers include JARID1B/KDM5B, JARID1C/KDM5C, p300, CBP, PARP1, SetDB1 and MBD1. Whereas SUMOylated JARID1B was ubiquitylated by the SUMO-targeted ubiquitin ligase RNF4 and degraded by the proteasome in response to DNA damage, JARID1C was SUMOylated and recruited to the chromatin to demethylate histone H3K4.
Project description:Human epidermal keratinocytes were treated with 25 ng.ml EphB2 or EFNA4, both as-Fc conjugates (Sigma). Human epidermal keratinocytes are treated with 25 ng/ml EphB2 or EFNA4 Fc conjugates in a 48hr time course.
Project description:Ubiquitylation is an essential post-translational modification that regulates numerous cellular processes, most notably protein degradation. Ubiquitin itself can be post-translationally modified by phosphorylation, with nearly every serine, threonine, and tyrosine residue having the potential to be phosphorylated. However, the effect of this modification on ubiquitin function is largely unknown. Here, we performed in vivo and in vitro characterization of the effects of phosphorylation of yeast ubiquitin at position serine 65. We find ubiquitin S65 phosphorylation to be regulated under oxidative stress, occurring in tandem with the restructuring of the ubiquitin landscape into a highly polymeric state. Phosphomimetic mutation of S65 recapitulates the oxidative stress phenotype, causing a dramatic accumulation of ubiquitylated proteins and a proteome-wide reduction of protein turnover rates. Importantly, this mutation impacts ubiquitin chain disassembly, chain linkage distribution, and substrate targeting. These results demonstrate that phosphorylation represents an additional mode of ubiquitin regulation with broad implications in cellular physiology.
Project description:Acetylation of transcriptional regulators is normally dynamically regulated by nutrient status but is often persistently elevated in nutrient-excessive obesity conditions. We investigated the functional consequences of such aberrantly elevated acetylation of the nuclear receptor FXR as a model. Proteomic studies identified K217 as the FXR acetylation site in diet-induced obese mice. In vivo studies utilizing acetylation-mimic and -defective K217 mutants and gene expression profiling revealed that FXR acetylation increased proinflammatory gene expression, macrophage infiltration, and liver cytokine and triglyceride levels, impaired insulin signaling, and increased glucose intolerance. Mechanistically, acetylation of FXR blocked its interaction with the SUMO ligase PIASy and inhibited SUMO2 modification at K277, resulting in activation of inflammatory genes. SUMOylation of agonist-activated FXR increased its interaction with NF-κB but blocked that with RXRα, so that SUMO2-modified FXR was selectively recruited to and trans-repressed inflammatory genes without affecting FXR/RXRα target genes. A dysregulated Acetyl/SUMO switch of FXR in obesity may serve as a general mechanism for diminished anti-inflammatory response of other transcriptional regulators and provide potential therapeutic and diagnostic targets for obesity-related metabolic disorders. FXR-WT or the FXR-K217Q mutant was expressed in lean mice and FXR-WT or the FXR-K217R mutant was expressed in obese mice by adenoviral infection. One week after infection, mice were treated with GW4064 (30 mg/kg in corn oil) overnight before sacrifice and hepatic expression was analyzed by Illumina microarray.
Project description:Chromatin immunoprecipitation of FOXK2 (tagged with Flag and His tags) in U2OS cells detected by SOLiD sequencing. ***Correction March 2014: The sample “FOXK2_Dox_treated” has been renamed, it was originally named “FOXK2_rep2”. A new sample “FOXK2_rep2” has been added, with new files. It has come to our attention that one of the FOXK2 ChIP-seq replicates 'FOXK2_rep2' that we used in our paper recent paper (Ji, Z., Donaldson, I.J., Liu, J., Hayes, A., Zeef, L.A.H. and Sharrocks, A.D. (2012) The forkhead transcription factor FOXK2 promotes AP-1-mediated transcriptional regulation. Mol. Cell. Biol. 32, 385-398. doi:10.1128/MCB.05504-11) was incorrect. The replicate was actually treated with doxorubicin prior to ChIP-seq analysis resulting in the loss of many FOXK2 binding events.***