Biophysical Society Thematic Meeting | Tutzing 2026

Single-Molecule FRET: The Next 30 Years

Poster Abstracts

2-POS Board 2 UNCOVERING THE INTRAMOLECULAR INTERACTIONS OF ER-PHAGY RECEPTORS: WHAT WE CAN LEARN FROM FRET AND DNA-PAINT STUDIES? Pooyeh Asadiatouei 1 ; Ashwin Balakrishnan 1 ; Katharina Lorentzen 2 ; Alexandra Stolz 2 ; Mike Heilemann 1 ; 1 Goethe University Frankfurt, Institute for Physical and Theoretical Chemistry, Frankfurt am Main, Germany 2 Goethe University Frankfurt, Buchmann Institute for Molecular Life Sciences (BMLS), Frankfurt am Main, Germany Selective autophagy of the endoplasmic reticulum (ER-phagy) has come of age, with over eight receptors discovered in humans that function in helping a cell sustain through ER stress. Most studies on ER-phagy receptors have been focused on uncovering how they affect ER-phagy process from a biochemical perspective 1 ; information on their dynamics, spatial organization and compartmentalization across the cell and the ER is currently missing. In this study, we employ fluorescence microscopy to specifically visualize the spatial distribution, clustering and co-organization of ER-phagy receptors FAM134B and FAM134C in cells. Since fluorescence microscopy inherently is limited by diffraction, we employ DNA based points accumulation for imaging nanoscale topography (DNA-PAINT) as a super-resolution technique to map the nano scale pattern of FAM134B/C in cells with a spatial resolution below 20 nm 2 . In order to map the internal organization of FAM134B/C clusters, we use Förster Resonance Energy Transfer (FRET). After carefully correcting the apparent FRET efficiency values, the accurate FRET signals help us realize the spatial status of labeled receptors in the distance ranges below 10 nanometers and extract the kinetic information in case of possible dynamics between FRET pairs 3 . Combining results from FRET and DNA-PAINT experiments, we investigate the spatial organization of FAM134B/C from the molecular to the cellular length scale, and aim to elucidate the molecular mechanism that initiates ER-phagy. References:(1) Stolz, A.; Grumati, P. The Various Shades of ER-Phagy. FEBS J. 2019, 286 (23), 4642–4649.(2) Schnitzbauer, J.; Strauss, M. T.; Schlichthaerle, T.; Schueder, F.; Jungmann, R. Super-Resolution Microscopy with DNA PAINT. 2017, 12 (6), 1198–1228.(3) Bilgen, E, Lamb, D., C., Multicolor single-molecule FRET studies on dynamic protein systems. Curr. Opin. Struct. Biol. 2025, 93,103117

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