Poster abstracts
Poster number 38 submitted by Guoming Gao
Probing the impact of HOPS on RNAs with single molecule tracking
Guoming Gao (Biophysics Graduate Program and Department of Biophysics, University of Michigan, Ann Arbor, MI 48109, USA), Nils G Walter (Department of Chemistry, Biophysics, and Center for RNA Biomedicine, University of Michigan, Ann Arbor, MI 48109, USA)
Abstract:
Proteins and RNAs can form functional biological condensates, also known as membraneless organelles, via liquid-liquid phase separation (LLPS). The partitioning of different proteins and RNAs between the dilute phase and the condensed phase provides delicate regulation over their functions, from promoting biochemical reactions and specific intermolecular interactions, to sequestering key molecules from downstream processing or signaling. Hyperosmotic phase separation (HOPS) is a recently discovered LLPS triggered by the osmotic compression of cell volume. A majority of homo-multimeric proteins are shown to undergo HOPS in several cell types. Moreover, HOPS is much faster than most cellular LLPS processes (within ~10 s versus over minutes to hours), and thus HOPS condensates could be first responders sensing cell volume change and priming other stress responses. However, it was unclear whether RNAs contribute to HOPS and how HOPS impacts the diffusion behaviors and functions of different RNAs. Here, we used live-cell single molecule RNA tracking to explore the dwelling of mRNAs, lncRNAs, and miRNAs in HOPS condensates, and measure the change in their diffusion behaviors in the presence of HOPS. A theoretical model for RNA’s role in HOPS is proposed based on RNA interactions with enigmatic RNA binding sites (EnigmRBS) on protein surfaces.
Keywords: LLPS, Single Molecule