Poster abstracts
Poster number 75 submitted by Xiaoyan Li
Identifying the mechanism of PUS7 relocalization upon stress
Xiaoyan Li (University of Michigan, Department of Chemistry), Kristin S. Koutmou (University of Michigan, Department of Chemistry)
Abstract:
Pseudouridine (Ψ) is one of the most abundant and conserved post-transcriptional RNA modifications. It plays critical roles in modulating RNA substrate, stability, and RNA-protein interactions. In eukaryotes, pseudouridine synthase 7 (PUS7) catalyzes Ψ incorporation into key RNA substrates for the ribosome, tRNA, and mRNA, within UNUAR sequence motifs. These sites of modification have the potential to regulate cellular protein production. In line with this possibility, mutations and dysregulation of PUS7 have been implicated in diverse diseases such as intellectual disabilities and cancers. Recent work from our lab demonstrated that PUS7 undergoes stress-induced relocalization from the nucleus to the cytoplasm in both yeast and human lung cells. This shift in PUS7 subcellular localization correlates with increased mRNA pseudouridylation, enhanced cellular stress tolerance, and widespread proteomics remodeling. Here, we explore one possible mechanism to explain the PUS7 pseudouridylation-mediated changes in protein expression that we observed. The PUF family of RNA-binding proteins regulates many aspects of RNA biology, including splicing, maturation, transport, and translation. Many PUF proteins recognize the same UNUAR motif modified by PUS7, suggesting the potential for regulatory cross-talk. This study aims to define the protein-protein interactions involved in PUS7 nuclear-cytoplasmic transport, characterize its nuclear localization and export signals, and explore its functional interplay with PUF proteins under stress. To achieve these goals, we employ proximity-dependent biotin labeling, co-immunoprecipitation, liquid chromatography–mass spectrometry (LC-MS), and direct RNA nanopore sequencing to dissect the regulatory network controlling stress-responsive pseudouridylation.
Keywords: PUS7, stress , protein-protein interactions