Biology subjects

Eiring, P.

Publications and source records attributed to Eiring, P..

3 recordsLinked to original sources

bioRxiv2026

Structural cell biology by mega-expansion microscopy

Structural characterization of macromolecular assemblies within intact cells remains one of the central challenges in cell biology. While cryo-electron tomography provides unparalleled structural information, its applicability is limited by sample thickness, imaging throughput, and accessibility. Fluorescence microscopy offers molecular specificity and compatibility with intact biological specimens but has so far lacked the spatial resolution required to visualize cellular ultrastructure. Here we introduce Mega-expansion microscopy (Mega-ExM), a fluorescence imaging approach that enables structural visualization of whole cells using conventional confocal microscopes. Mega-ExM combines iterative hydrogel expansion with whole-proteome NHS-dye labeling and post-expansion immunostaining to achieve tunable expansion factors of up to [~]1,500-fold while preserving ultrastructure. At expansion factors of 40-260x, Mega-ExM resolves centrioles, mitochondrial cristae, protein-dense domains within mitochondrial cristae consistent with respiratory-chain supercomplexes, the synaptonemal complex, and nuclear pore complexes (NPCs) with high fidelity. Particle averaging of [~]200x expanded NPCs yields reconstructions with a structural resolution of [~]35 [A], approaching what cryo-electron tomography has achieved for selected protein assemblies. By combining molecular specificity, large imaging volumes, and nanoscale structural resolution on conventional fluorescence microscopes, Mega-ExM establishes a broadly accessible platform for in situ structural biology.

biophysics↗

bioRxiv2025

Single-molecule localization microscopy reveals the molecular organization of endogenous membrane receptors

Super-resolution microscopy in combination with genetic labeling methods allows imaging of single proteins in cells. However, visualizing endogenous proteins on primary cells remains challenging due to the use of sterically demanding antibodies for labeling. Here, we demonstrate how immunolabeling conditions and antibody crosslinking influence the quantification and identification of membrane receptor stoichiometry on cells using single-molecule localization microscopy. We developed an optimized immunolabeling and analysis protocol and demonstrate the performance of the approach by resolving the molecular organization of endogenous CD45, CD69, and CD38 on Jurkat T cells. To demonstrate the usefulness of the method for immunotherapy applications we investigated the interaction of primary multiple myeloma cells with the therapeutic monoclonal antibodies (mAbs) daratumumab and isatuximab, and a polyclonal anti-CD38 antibody. Our approach might lay the foundation for improved personalized diagnostics and treatment with therapeutic antibodies. One-Sentence SummarySingle-molecule localization microcopy quantifies the expression and resolves the stoichiometry of endogenous membrane receptors

biophysics↗

bioRxiv2023

Coronaviruses use ACE2 monomers as entry receptors

The angiotensin-converting enzyme 2 (ACE2) has been identified as entry receptor on cells enabling binding and infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) via trimeric spike (S) proteins protruding from the viral surface1,2. It has been suggested that trimeric S proteins preferably bind to plasma membrane areas with high concentrations of preferably multimeric ACE2 receptors to achieve a higher binding and infection efficiency1,3. However, our current knowledge about the influence of ACE2 expression and organization in the plasma membrane on SARS-CoV-2 infection efficiency remains elusive. Here we used direct stochastic optical reconstruction microscopy (dSTORM) in combination with different labeling approaches to visualize the distribution and quantify the expression of ACE2 on different cells. Our results reveal that endogenous ACE2 receptors are present as monomers in the plasma membrane with densities of only 1-2 receptors m-2. In addition, binding of trimeric S proteins does not induce clustering of ACE2 receptors in the plasma membrane. Supported by infection studies using vesicular stomatitis virus (VSV) particles bearing S proteins our data demonstrate that a single S protein interaction per virus particle with a monomeric ACE2 receptor is sufficient for infection which attests SARS-CoV-2 a high infectivity.

molecular biology↗