Study Maps Selenoprotein S Interactions, Linking It to Protein Translation and Membrane Biogenesis
Researchers used affinity purification, in vivo crosslinking, and proteomics to map the full interactome of human selenoprotein S (SELENOS), a stress-response protein linked to metabolic disease. They found SELENOS associates with complexes involved in inserting membrane proteins into the endoplasmic reticulum, as well as metabolic, trafficking, and mitochondrial pathways. The findings identify SELENOS's C-terminal redox loop as a key hub connecting cellular translation machinery with ER membrane protein biogenesis and quality control.
Human selenoprotein S (SELENOS) is a component of the integrated cellular stress response and has been genetically linked to increased risk for diabetes, dyslipidemia, and cardiovascular disease, yet its precise molecular roles have remained difficult to pin down due to its involvement in diverse protein complexes. To address this, researchers employed affinity purification combined with in vivo crosslinking to capture both stable and transient protein interactions, then used proteomics to comprehensively catalog the SELENOS interactome. The resulting map revealed that SELENOS associates with complexes responsible for inserting membrane proteins into the ER bilayer and with connected quality control machinery. SELENOS was also found in metabolic, vesicular trafficking, and mitochondrial pathways, suggesting broad cellular involvement. A particularly notable finding was that translation-related proteins preferentially interact with SELENOS when its C-terminal intrinsically disordered region — which contains a redox-active motif — is accessible. This positions the C-terminal redox loop as a central molecular hub that physically and functionally connects the translation apparatus with ER membrane protein biogenesis. The work provides a framework for understanding how SELENOS dysfunction may contribute to the metabolic and cardiovascular diseases with which its genetic variants are associated.
What's missing
As a preprint posted to bioRxiv, this study has not yet undergone formal peer review, and its findings should be considered preliminary. The study does not address whether disease-associated SELENOS polymorphisms specifically disrupt the C-terminal redox loop interactions identified here, leaving the direct mechanistic link to diabetes or cardiovascular disease unestablished. Additionally, the interactome was mapped under specific experimental conditions, and it remains unclear how the interaction network changes under physiological stress states relevant to disease.
What different sources said
- bioRxivCenter
Selenoprotein S plays role in translation and membrane protein biogenesis
Related
Gut Bacteria Enzyme Found to Break Down Heat-Processed Food Compounds, Producing Novel Biogenic Amines
Researchers have discovered that an enzyme in common gut bacteria can degrade N-epsilon-carboxymethyllysine (CML), a compound formed during thermal food processing, producing previously unknown biogenic amines. The enzyme, ornithine decarboxylase SpeC from enterobacteria, acts on CML and related modified lysine derivatives through a low-level 'underground' catalytic activity. This finding suggests a previously unrecognized communication axis between thermally processed dietary compounds and gut microbial physiology, with potential implications for host health.
Full-Length Gene Sequencing Reveals Two Distinct Bacterial Communities in Black-Legged Ticks Expanding Into Canada
Researchers used Oxford Nanopore full-length 16S rRNA gene sequencing to characterize the microbiome of Ixodes scapularis black-legged ticks collected in Nova Scotia, Canada, distinguishing between tick-adapted bacteria and environmentally acquired bacteria. The study comes as I. scapularis — the primary vector of Lyme disease — is rapidly expanding northward into Canada due to climate change. The findings suggest that environmentally derived bacteria in tick microbiomes are not mere contamination, which has implications for how tick microbiome data is collected and interpreted across surveillance studies.
Study Identifies Metabolic Link Between Cell Envelope Stress and Biofilm Formation in Bacteria
Researchers have discovered that the metabolite acetyl-CoA directly inhibits enzymes that degrade the bacterial signaling molecule c-di-GMP, connecting cell envelope biosynthesis stress to biofilm formation in Pseudomonas aeruginosa. The study found that sub-inhibitory concentrations of antibiotics targeting early peptidoglycan biosynthesis — but not other antibiotic classes — elevate c-di-GMP levels by reducing phosphodiesterase activity, with acetyl-CoA competing for the enzyme active site. Because the relevant enzyme domain is broadly conserved across bacterial species, this checkpoint mechanism may be widespread and could have implications for understanding antibiotic-induced biofilm responses.