Biophysical Society Thematic Meeting | Tutzing 2026

Single-Molecule FRET: The Next 30 Years

Thursday Speaker Abstracts

DIFFERENT PERSONALITIES OF PHASE-SEPARATING PROTEINS REVEAL MULTIPLE RNA BINDING MODES Andreas Hartmann 1 ; Lukáš Pekárek 1,2,3 ; Anastasiia Chinakova 2 ; María del Sol Reyes Ortiz 1 ; Irmela R. E. A. Trussina 2 ; Shashank Shekhar 1,2,3 ; Titus M. Franzmann 2 ; Marcus Jahnel 2,3 ; Simon Alberti 2,3 ; Michael Schlierf 1,3,4 ; 1 B CUBE Center for Molecular Bioengineering, TU Dresden, Dresden, Germany 2 Biotechnology Center, Center for Molecular and Cellular Bioengineering, TU Dresden, Dresden, Germany 3 Excellence Cluster Physics of Life, TU Dresden, Dresden, Germany 4 Faculty of Physics, TU Dresden, Dresden, Germany RNA binding proteins (RBPs) are involved in a vast number of functions within the cell including the regulation of gene expression, protein synthesis, RNA splicing, and stress responses in eukaryotic cells. Interestingly, many of the RBPs contain charged intrinsically disordered regions (IDRs) regulating the interaction with RNA backbone and thereby the formation of biomolecular networks and condensates. Investigating the assembly mechanism of protein-RNA networks and the intricate regulation of biomolecular condensates by IDRs remains a challenging task. Here we compare the RNA binding mechanism on the single-molecule level for three RBPs: G3BP1, FXR1, and YBX1, which are involved in stress granule formation and RNA transportation, respectively. Therefore, we employed metastable RNA hairpin structures exhibiting interconversion dynamics on the millisecond timescale. While the diffusion time of the molecule directly probed the interaction of the RBPs with the RNA, the altered molecular conformation and dynamics probed by Förster resonance energy transfer (FRET) revealed different binding modes for G3BP1, FXR1, and YBX1. The contrasting effects of secondary structure de-/stabilization and RNA linearization shed light on the complex conformational landscape explored by RNA within differently composed biomolecular condensates.

52