Biology subjects

Board, S.

Publications and source records attributed to Board, S..

4 recordsLinked to original sources

bioRxiv2025

Super-resolution live-cell mapping of protein-protein interactions using chemogenetic split reporters and STED microscopy

The ability to map protein-protein interactions (PPI) within living cells at high spatial resolution is essential for unravelling their roles in cellular biology. Although several super-resolution microscopy techniques are available, visualizing PPI below the diffraction limit of light across entire live cells remains a challenge. Here, we introduce an approach that combines the chemogenetic split fluorescent reporter splitFAST2 with STED microscopy for sub-diffraction imaging of PPI. As the fluorescence of splitFAST2 is activated only where the two proteins interact, this system allows for highly precise and unambiguous localization in live cells, enhanced further by the rapid super-resolution imaging capabilities of STED. The improved spatial resolution of our approach enabled us to precisely map the subcellular localization of inducible interactions or constitutive interactions. Beyond simply detecting PPIs below the diffraction limit in whole living cells, we also demonstrated that splitFAST2 can serve as the basis for fluorescent probes with very low background, enabling effective subdiffraction imaging of repetitive cellular structures like filamentous actin and microtubules.

biophysics↗

bioRxiv2024

Novel Oral Adjuvant to Enhance Cytotoxic Memory-Like NK Cell Responses in an HIV Vaccine Platform

Antibody-dependent cell-mediated cytotoxicity, mediated by natural killer (NK) cells and antibodies, emerged as a secondary correlate of protection in the RV144 HIV vaccine clinical trial, the only vaccine thus far demonstrating some efficacy in human. Therefore, leveraging NK cells with enhanced cytotoxic effector responses may bolster vaccine induced protection against HIV. Here, we investigated the effect of orally administering indole-3-carbinol (I3C), an aryl hydrocarbon receptor (AHR) agonist, as an adjuvant to an RV144-like vaccine platform in a mouse model. We demonstrate the expansion of KLRG1-expressing NK cells induced by the vaccine together with I3C. This NK cell subset exhibited enhanced vaccine antigen-specific cytotoxic memory-like features. Our study underscores the potential of incorporating I3C as an oral adjuvant to HIV vaccine platforms to enhance antigen-specific (memory-like) cytotoxicity of NK cells against HIV-infected cells. This approach may contribute to enhancing the protective efficacy of HIV preventive vaccines against HIV acquisition.

immunology↗

bioRxiv2023

Enzyme-less nanopore detection of post-translational modifications within long polypeptides

Means to sequence DNA and RNA quickly and cheaply have revolutionized biology and medicine. The ability to analyse cellular proteins and their millions of variants would be an advance of comparable importance, but requires a fresh technical approach. We use electroosmosis for the non-enzymatic capture, unfolding and translocation of individual polypeptides of more than 1200 residues by a protein nanopore. By monitoring the ionic current carried by the nanopore, we locate post-translational modifications deep within the polypeptide chains, and thereby lay the groundwork for obtaining inventories of the proteoforms in cells and tissues.

biochemistry↗

bioRxiv2020

Molecular fluctuations as a ruler of force-induced protein conformations

Molecular fluctuations directly reflect the underlying energy landscape. Variance analysis can probe protein dynamics in several biochemistry-driven approaches, yet measurement of probe-independent fluctuations in proteins exposed to mechanical forces remains only accessible through steered molecular dynamics simulations. Using single molecule magnetic tweezers, here we conduct variance analysis to show that individual unfolding and refolding transitions occurring in dynamic equilibrium in a single protein under force are hallmarked by a change in the protein's end-to-end fluctuations, revealing a change in protein stiffness. By unfolding and refolding three structurally distinct proteins under a wide range of constant forces, we demonstrate that the associated change in protein compliance to reach force-induced thermodynamically-stable states scales with the protein's contour length, in agreement with the sequence-independent FJC model of polymer physics. Our findings will help probe the conformational dynamics of proteins exposed to mechanical force at high resolution, of central importance in mechanosensing and mechanotransduction.

biophysics↗