bioRxiv Science⌕ Search

Biology subjects

Hybiske, K.

Publications and source records attributed to Hybiske, K..

3 recordsLinked to original sources

Intracellular pathogen targeting by IL32 elicits cell-autonomous immunity

Interferon-{gamma} safeguards humans against intracellular pathogens, yet how most interferon-stimulated genes protect host cells, and how human-adapted pathogens evade these defenses is unclear1,2. Here, we discover a potent immune surveillance and effector circuit executed by an intracellularly acting cytokine, IL32, that targets and restricts phylogenetically distinct vacuolar pathogens, including the bacterium Chlamydia and the microsporidian Encephalitozoon. Quantitative proteomics coupled to a tailored CRISPR screen, uncovered components of the cysteine/Arg N-degron pathway3 that modify IL32 through oxidation-dependent arginylation, thereby enabling the recruitment of the autophagy machinery to pathogen-containing vacuoles. A forward genetics screen in Chlamydia trachomatis, the leading cause of sexually transmitted bacterial infection, identified the secreted virulence factor IncS as an evasion factor that blocks IL32 targeting and shields this human pathogen from xenophagy. These findings establish an IL32-dependent intracellular sensing mechanism linking IFN{gamma} signaling to N-degron-mediated xenophagy, revealing a broadly relevant axis of human host-pathogen conflict.

immunology↗

Wikidata as a FAIR knowledge graph for the life sciences

Wikidata is a community-maintained knowledge base that epitomizes the FAIR principles of Findability, Accessibility, Interoperability, and Reusability. Here, we describe the breadth and depth of biomedical knowledge contained within Wikidata, assembled from primary knowledge repositories on genomics, proteomics, genetic variants, pathways, chemical compounds, and diseases. We built a collection of open-source tools that simplify the addition and synchronization of Wikidata with source databases. We furthermore demonstrate several use cases of how the continuously updated, crowd-contributed knowledge in Wikidata can be mined. These use cases cover a diverse cross section of biomedical analyses, from crowdsourced curation of biomedical ontologies, to phenotype-based diagnosis of disease, to drug repurposing.

bioinformatics↗

Proximity-dependent proteomics of the Chlamydia trachomatis inclusion membrane reveals functional interactions with endoplasmic reticulum exit sites

Chlamydia trachomatis is the most common bacterial sexually transmitted infection, responsible for millions of infections each year. Despite this high prevalence, the elucidation of the molecular mechanisms of Chlamydia pathogenesis has been difficult due to limitations in genetic tools and its intracellular developmental cycle. Within a host epithelial cell, chlamydiae replicate within a vacuole called the inclusion. Many Chlamydia-host interactions are thought to be mediated by the Inc family of type III secreted proteins that are anchored in the inclusion membrane, but their array of host targets are largely unknown. To investigate how the inclusion membrane proteome changes over the course of an infected cell, we have adapted the APEX system of proximity-dependent biotinylation. APEX is capable of specifically labeling proteins within a 20 nm radius in living cells. We transformed C. trachomatis to express the enzyme APEX fused to known inclusion membrane proteins, allowing biotinylation and pull-down of inclusion-associated proteins. Using quantitative mass spectrometry against APEX labeled samples, we identified over 400 proteins associated with the inclusion membrane at early, middle, and late stages of epithelial cell infection. This system was sensitive enough to detect inclusion interacting proteins early in the developmental cycle, at 8 hours post infection, a previously intractable time point. Mass spectrometry analysis revealed a novel, early association between C. trachomatis inclusions and endoplasmic reticulum exit sites (ERES), functional regions of the ER where COPII-coated vesicles originate. Pharmacological and genetic disruption of ERES function severely restricted early chlamydial growth and the development of infectious progeny. APEX is therefore a powerful in situ approach for identifying critical protein interactions on the membranes of pathogen-containing vacuoles. Furthermore, the data derived from proteomic mapping of Chlamydia inclusions has illuminated an important functional role for ERES in promoting chlamydial developmental growth.

microbiology↗