Project description:Enzymes that bind and process ubiquitin, a small 76 amino acid protein, have been recognized as pharmacological targets in oncology, immunological disorders and neurodegeneration. Mass spectrometry technology has now reached the capacity to cover the proteome with enough depth to interrogate entire biochemical pathways including those that contain DUBs and E3 ligase substrates. We have recently characterized the breast cancer cell (MCF7) deep proteome by detecting and quantifying ~10,000 proteins, and within this data set, we can detect endogenous expression of 65 deubiquitylating enzymes (DUBs), whereas matching transcriptomics detected 78 DUB mRNAs. Since enzyme activity provides another meaningful layer of information in addition of the expression levels, we have combined advanced mass spectrometry technology, pre-fractionation and more potent/selective ubiquitin active-site probes with propargyl based electrophiles to profile 74 DUBs including distinguishable isoforms for five DUBs in MCF7 crude extract material. Competition experiments with cysteine alkylating agents, pan-DUB inhibitors ubiquitin combined with probe labelling revealed the proportion of active cellular DUBs directly engaged with probes by label-free quantitative (LFQ) mass spectrometry, demonstrating that USP13, 39 and USP40 are non-reactive to probe, reflecting no, low or restricted enzymatic activity under these cellular conditions. Our extended chemoproteomics workflow increases depth of covering the active DUBome, including isoform-specific resolution, and provides the framework for more comprehensive cell-based small molecule DUB selectivity profiling.
Project description:Enzymes that bind and process ubiquitin, a small 76 amino acid protein, have been recognized as pharmacological targets in oncology, immunological disorders and neurodegeneration. Mass spectrometry technology has now reached the capacity to cover the proteome with enough depth to interrogate entire biochemical pathways including those that contain DUBs and E3 ligase substrates. We have recently characterized the breast cancer cell (MCF7) deep proteome by detecting and quantifying ~10,000 proteins, and within this data set, we can detect endogenous expression of 65 deubiquitylating enzymes (DUBs), whereas matching transcriptomics detected 78 DUB mRNAs. Since enzyme activity provides another meaningful layer of information in addition of the expression levels, we have combined advanced mass spectrometry technology, pre-fractionation and more potent/selective ubiquitin active-site probes with propargylic based electrophiles to profile 74 DUBs including distinguishable isoforms for five DUBs in MCF7 crude extract material. Competition experiments with cysteine alkylating agents, pan-DUB inhibitors combined with probe labelling revealed the proportion of active cellular DUBs directly engaged with probes by label-free quantitative (LFQ) mass spectrometry. This demonstrated that USP13, 39 and 40 are non-reactive to probe, indicating restricted enzymatic activity under these cellular conditions. Our extended chemoproteomics workflow increases depth of covering the active DUBome, including isoform-specific resolution, and provides the framework for more comprehensive cell-based small molecule DUB selectivity profiling.
Project description:Enzymes that bind and process ubiquitin, a small 76-amino-acid protein, have been recognized as pharmacological targets in oncology, immunological disorders, and neurodegeneration. Mass spectrometry technology has now reached the capacity to cover the proteome with enough depth to interrogate entire biochemical pathways including those that contain DUBs and E3 ligase substrates. We have recently characterized the breast cancer cell (MCF7) deep proteome by detecting and quantifying ~10,000 proteins, and within this data set, we can detect endogenous expression of 65 deubiquitylating enzymes (DUBs), whereas matching transcriptomics detected 78 DUB mRNAs. Since enzyme activity provides another meaningful layer of information in addition to the expression levels, we have combined advanced mass spectrometry technology, pre-fractionation, and more potent/selective ubiquitin active-site probes with propargylic-based electrophiles to profile 74 DUBs including distinguishable isoforms for 5 DUBs in MCF7 crude extract material. Competition experiments with cysteine alkylating agents and pan-DUB inhibitors combined with probe labeling revealed the proportion of active cellular DUBs directly engaged with probes by label-free quantitative (LFQ) mass spectrometry. This demonstrated that USP13, 39, and 40 are non-reactive to probe, indicating restricted enzymatic activity under these cellular conditions. Our extended chemoproteomics workflow increases depth of covering the active DUBome, including isoform-specific resolution, and provides the framework for more comprehensive cell-based small-molecule DUB selectivity profiling.
Project description:Ubiquitination/deubiquitination belong to the most important regulatory mechanisms carried out through the attachment/removal of the ubiquitin molecule, respectively. The process is necessary not only to mark molecules for degradation, but also for example to the activation of signaling pathways leading to pro-inflammatory host response. Many intracellular pathogens, such as Francisella tularensis, have evolved mechanisms of blocking such host immune responses to escape degradation. Here, we describe that F. tularensis interferes with the host's ubiquitination system. We showed increased total activity of deubiquitinating enzymes (DUBs) in human macrophages after infection and confirmed the reduced enzymatic activities of two specific DUBs: USP10 and UCH-L5, and the increased activity of USP25. We further revealed the enrichment of these three enzymes in exosomes derived from F. tularensis-infected cells.
Project description:This data set contains all raw data files in the mzXML (for LC-MS data) format that belongs to the manuscript "Competition or indifference: Neutron-Encoding to profile linkage selectivity of deubiquitinating enzymes" by Bianca D. M. van Tol, Bjorn R. van Doodewaerd, Guinevere S. M. Lageveen-Kammeijer, Bas C. Jansen, Cami M. P. Talavera Ormeno, Paul J. M. Hekking, Aysegul Sapmaz, Robbert Q. Kim, Angeliki Moutsiopoulou, David Komander, Manfred Wuhrer, Gerbrand J. van der Heden van Noort, Huib Ovaa, Paul P. Geurink
Project description:The ubiquitin-proteasome axis has been extensively explored at a system-wide level, but the impact of deubiquitinating enzymes (DUBs) on the ubiquitinome remains largely unknown. Using UbiSite technology and inhibitors, we have compared the contributions of the proteasome and DUBs on the ubiquitinome. We uncovered large differential dynamic Ub signalling networks with substrates and sites uniquely regulated by DUBs or by the proteasome, highlighting the role of DUBs in degradation-independent ubiquitin signalling. DUBs regulate substrates via nearly 40,000 unique sites. Moreover, we found that ubiquitin conjugated to SUMO2/3 forms a unidirectional proteasomal degradation signal with strikingly rapid kinetics compared to ubiquitin polymers only. We found that PARP1, is hyper ubiquitinated in response to DUB inhibition, increasing its enzymatic activity. Our findings highlight the key regulatory roles of DUBs on ubiquitin dynamics.
Project description:The ubiquitin-proteasome axis has been extensively explored at a system-wide level, but the impact of deubiquitinating enzymes (DUBs) on the ubiquitinome remains largely unknown. Using UbiSite technology and inhibitors, we have compared the contributions of the proteasome and DUBs on the ubiquitinome. We uncovered large differential dynamic Ub signalling networks with substrates and sites uniquely regulated by DUBs or by the proteasome, highlighting the role of DUBs in degradation-independent ubiquitin signalling. DUBs regulate substrates via nearly 40,000 unique sites. Moreover, we found that ubiquitin conjugated to SUMO2/3 forms a unidirectional proteasomal degradation signal with strikingly rapid kinetics compared to ubiquitin polymers only. We found that PARP1, is hyper ubiquitinated in response to DUB inhibition, increasing its enzymatic activity. Our findings highlight the key regulatory roles of DUBs on ubiquitin dynamics.
Project description:The ubiquitin-proteasome axis has been extensively explored at a system-wide level, but the impact of deubiquitinating enzymes (DUBs) on the ubiquitinome remains largely unknown. Using UbiSite technology and inhibitors, we have compared the contributions of the proteasome and DUBs on the ubiquitinome. We uncovered large differential dynamic Ub signalling networks with substrates and sites uniquely regulated by DUBs or by the proteasome, highlighting the role of DUBs in degradation-independent ubiquitin signalling. DUBs regulate substrates via nearly 40,000 unique sites. Moreover, we found that ubiquitin conjugated to SUMO2/3 forms a unidirectional proteasomal degradation signal with strikingly rapid kinetics compared to ubiquitin polymers only. We found that PARP1 is hyper ubiquitinated in response to DUB inhibition, increasing its enzymatic activity. Our findings highlight the key regulatory roles of DUBs on ubiquitin dynamics.
Project description:Deubiquitinating enzymes (DUBs) catalyze the cleavage of ubiquitin from target proteins. Ubiquitin is post-translationally attached to proteins and serves as an important regulatory signal for key cellular processes. In this study, novel activity-based probes to study DUBs were synthesized that comprise a ubiquitin moiety and a novel disulfide warhead at the C-terminus. These reagents can bind DUBs covalently by forming a disulfide bridge between the active-site cysteine residue and the ubiquitin-based probe. As disulfide bridges can be broken by the addition of a reducing agent, these novel ubiquitin reagents can be used to capture and subsequently release catalytically active DUBs, whereas existing capturing agents bind irreversibly. These novel reagents allow for the study of these enzymes in their active state under various conditions.