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Molecular glue degraders are an effective therapeutic modality, but their design principles are not well understood. Recently, several unexpectedly diverse compounds were reported to deplete cyclin K by linking CDK12–cyclin K to the DDB1–CUL4–RBX1 E3 ligase. Here, to investigate how chemically dissimilar small molecules trigger cyclin K degradation, we evaluated 91 candidate degraders in structural, biophysical and cellular studies and reveal all compounds acquire glue activity via simultaneous CDK12 binding and engagement of DDB1 interfacial residues, in particular Arg928. While we identify multiple published kinase inhibitors as cryptic degraders, we also show that these glues do not require pronounced inhibitory properties for activity and that the relative degree of CDK12 inhibition versus cyclin K degradation is tuneable. We further demonstrate cyclin K degraders have transcriptional signatures …

Undifferentiated small round cell sarcomas of bone and soft tissue (USRS) are a group of tumors with heterogenic genomic alterations sharing similar morphology. In the present study, we performed a comparative large-scale proteomic analysis of USRS (n=42) with diverse genomic translocations including classic Ewing sarcomas with EWSR1::FLI1 fusions (n=24) or EWSR1::ERG – fusions (n=4), sarcomas with an EWSR1 – rearrangement (n=2), CIC::DUX4 fusion (n=8), as well as tumors classified as USRS with no genetic data available (n=4). Proteins extracted from formalin-fixed, paraffin-embedded (FFPE) pretherapeutic biopsies were analyzed qualitatively and quantitatively using shot gun mass spectrometry (MS). More than 8000 protein groups could be quantified using data-independent acquisition. Unsupervised hierarchical cluster analysis based on proteomic data allowed stratification of the 42 cases …

Recent improvements in proteomics technologies have fundamentally altered our capacities to characterize human biology. There is an ever-growing interest in using these novel methods for studying the circulating proteome, as blood offers an accessible window into human health. However, every methodological innovation and analytical progress calls for reassessing our existing approaches and routines to ensure that the new data will add value to the greater biomedical research community and avoid previous errors. As representatives of HUPO’s Human Plasma Proteome Project (HPPP), we present our 2024 survey of the current progress in our community, including the latest build of the Human Plasma Proteome PeptideAtlas that now comprises 4608 proteins detected in 113 data sets. We then discuss the updates of established proteomics methods, emerging technologies, and investigations of proteoforms …

Genome-scale perturbation screening is widely used to identify disease-relevant cellular proteins serving as potential drug targets. However, most biological processes are not compatible with commonly employed perturbation screening methods, which rely on FACS- or growth-based enrichment of cells. Optical pooled screening instead uses fluorescence microscopy to determine the phenotype in single cells, and subsequently to identify individual perturbagens in the same cells. Published methods rely on cytosolic detection of endogenously expressed barcoded transcripts, which limits application to large, transcriptionally active cell types, and often relies on local clusters of clonal cells for unequivocal barcode assignment, thus precluding genome-scale screening for many biological processes. Nuclear In-Situ Sequencing (NIS-Seq) solves these shortcomings by creating bright sequencing signals directly from nuclear genomic DNA, enabling screening any nucleus-containing cell type at high density and high library complexity. We benchmark NIS-Seq by performing three genome-scale optical screens in live cells, identifying key players of inflammation-related cellular pathways.

The implementation of targeted molecular therapies and immunotherapy in melanoma vastly improved the therapeutic outcome in patients with limited efficacy of surgical intervention. Nevertheless, a large fraction of patients with melanoma still remain refractory or acquire resistance to these new forms of treatment, illustrating a need for improvement. Here, we report that the clinically relevant combination of mitogen-activated protein (MAP) kinase pathway inhibitors dabrafenib and trametinib synergize with RIG-I agonist-induced immunotherapy to kill BRAF-mutated human and mouse melanoma cells. Kinase inhibition did not compromise the agonist-induced innate immune response of the RIG-I pathway in host immune cells. In a melanoma transplantation mouse model, the triple therapy outperformed individual therapies. Our study suggests that agonist-induced activation of RIG-I with its synthetic ligand 3pRNA …

Most techniques used to detect specific mRNAs in eukaryotic cells require to extract nucleic acids and thereby kill the cells. A programmable sensor for monitoring endogenous transcripts in living cells, in contrast, would enable to enrich living cells based on a specific transcription or splicing event, and studying these cells by live microscopy or sequencing methods requiring intact cells. We have engineered CRISPR-READ, a live cell RNA detector based on the CRISPR-associated Lon protease CalpL and a cA4-producing Type III CRISPR system. Upon RNA-programmable RNA sensing, CRISPR-READ produces an orthogonal second messenger, which leads to the cleavage of a dual FRET / localization reporter compatible with FACS sorting and live microscopy. Using this genetically encoded sensing circuit as a readout for a genome-wide CRISPR perturbation screen, we identified an extended Type-I interferon signaling cascade; RNA-Seq on sensor-sorted cells enabled unbiased identification of correlated stochasticity in gene expression across single cells.

Infectious respiratory diseases comprise the 4th most fatal group of diseases worldwide. Most studies on COVID-19 lack appropriate comparison to other viral pneumonias with similar severity. Here, we leverage the SCRIPT cohort at NWU Chicago for longitudinal proteomic profiling of bronchoalveolar lavage fluid (BALF) and patient plasma to analyze pathogen-specific differences during disease progression. We used mass spectrometry to analyze BALF and matched plasma from COVID-19 (n=14), bacterial pneumonia (n=8), influenza (n=8) patients, and non-pneumonia controls (n=8) at up to five time points after intubation in the intensive care unit.BALF of COVID-19 patients was specifically enriched in immunoglobulins, blood clotting proteins, and collagens, suggesting increased fibrogenesis and B-cell immunity already at the time of intubation compared to other bacterial or viral types of pneumonia. We …

CRISPR defence systems such as the well-known DNA-targeting Cas9 and the RNA-targeting type III systems are widespread in prokaryotes,. The latter orchestrates a complex antiviral response that is initiated through the synthesis of cyclic oligoadenylates after recognition of foreign RNA, –. Among the large set of proteins that are linked to type III systems and predicted to bind cyclic oligoadenylates,, a CRISPR-associated Lon protease (CalpL) stood out to us. CalpL contains a sensor domain of the SAVED family fused to a Lon protease effector domain. However, the mode of action of this effector is unknown. Here we report the structure and function of CalpL and show that this soluble protein forms a stable tripartite complex with two other proteins, CalpT and CalpS, that are encoded on the same operon. After activation by cyclic tetra-adenylate (cA4), CalpL oligomerizes and specifically cleaves the MazF …

Infectious respiratory diseases comprise the 4th most fatal group of diseases worldwide. Most studies on COVID-19 lack appropriate comparison to other viral pneumonias with similar severity. Here, we leverage the SCRIPT cohort at NWU Chicago for longitudinal proteomic profiling of bronchoalveolar lavage fluid (BALF) and patient plasma to analyze pathogen-specific differences during disease progression. We used mass spectrometry to analyze BALF and matched plasma from COVID-19 (n=14), bacterial pneumonia (n=8), influenza (n=8) patients, and non-pneumonia controls (n=8) at up to five time points after intubation in the intensive care unit.BALF of COVID-19 patients was specifically enriched in immunoglobulins, blood clotting proteins, and collagens, suggesting increased fibrogenesis and B-cell immunity already at the time of intubation compared to other bacterial or viral types of pneumonia. We …

Objective: Analysing the human blood proteome grants us an in-depth look into the health status of an individual and opens many avenues for the development of novel diagnostic and therapeutic methods. However, affinity-based techniques such as ELISA and immunoblotting, which are commonly used for single protein quantifications, are increasingly being replaced by mass spectrometry (MS)-based methods that can provide comprehensive results in even small sample volumes. Despite the attractiveness of MS-based workflows, there are prominent issues that still need to be addressed, most notably, the abundance of missingness in MS datasets as well as the lack of cell type resolution in bulk tissues MS. Therefore, our goal is to develop a pipeline that is able to impute these missing values and perform cell type deconvolution from MS blood proteomics data.Methods and results: Based on pre-existing MS …

Colonic adenomatous polyps, or adenomas, are frequent precancerous lesions and the origin of most cases of colorectal adenocarcinoma. However, we know from epidemiologic studies that although most colorectal cancers (CRCs) originate from adenomas, only a small fraction of adenomas (3%–5%) ever progress to cancer. At present, there are no molecular markers to guide follow-up surveillance programs.We profiled, by mass spectrometry–based proteomics combined with machine learning analysis, a selected cohort of formalin-fixed, paraffin-embedded high-grade (HG) adenomas with long clinical follow-up, collected as part of the Danish national screening program. We grouped subjects in the cohort according to their subsequent history of findings: a nonmetachronous advanced neoplasia group (G0), with no new HG adenomas or CRCs up to 10 years after polypectomy, and …

Multi‐omics analyses are used in microbiome studies to understand molecular changes in microbial communities exposed to different conditions. However, it is not always clear how much each omics data type contributes to our understanding and whether they are concordant with each other. Here, we map the molecular response of a synthetic community of 32 human gut bacteria to three non‐antibiotic drugs by using five omics layers (16S rRNA gene profiling, metagenomics, metatranscriptomics, metaproteomics and metabolomics). We find that all the omics methods with species resolution are highly consistent in estimating relative species abundances. Furthermore, different omics methods complement each other for capturing functional changes. For example, while nearly all the omics data types captured that the antipsychotic drug chlorpromazine selectively inhibits Bacteroidota representatives in the …