Deubiquitinases (DUBs) are key regulators of cellular homeostasis that reverse ubiquitination to control protein stability and signalling. The largest DUB family, the Ubiquitin Specific Proteases (USPs), includes USP10 - a versatile enzyme involved in DNA damage response, autophagy, ribosome quality control (RQC) several other pathways. USP10 interacts with G3BP1, a core stress granule (SG) nucleator, and this complex has a well-established role in RQC. Despite its functional significance, the structural basis of USP10 - G3BP1 interaction remains poorly defined.
USP10 binds G3BP1 via a conserved N-terminal hydrophobic motif (FGDF) that docks into the NTF2-like domain of G3BP1 - a binding pocket also recognized by other such as the RNA binding protein, Caprin1, and the viral Nsp3. In this study, we explored the interactions in detail using fluorescence polarization, NMR spectroscopy, and SEC-MALS. In addition to the canonical binding motif, we identified further interactions in the disordered N-terminus of USP10, suggesting a multivalent interaction landscape.
Our findings indicate that G3BP1 and USP10 interactions facilitate oligomeric complexes, potentially enhancing their scaffolding roles in cellular condensates. Further studies would investigate the physiological relevance of the higher order structures using cellular, structural, and biochemical approaches.