SUMO-2 activity is inhibited by non-covalent interactions with the Aβ peptide: an exploration of potential pathogenic mechanisms in Alzheimer's disease

: SUMOylation is a post-translational modification involving the addition of SUMO isoforms to target proteins and plays a role in various biological processes, including neurodegenerative diseases and ocular pathologies. This study investigates the interaction between SUMO-2 and amyloid (Aβ) peptides, key contributors to Alzheimer's disease, using techniques like cross-linking mass spectrometry, surface plasmon resonance and biolayer interferometry. Data are available via ProteomeXchange with identifier PXD066055. The results show that Aβ1-40 and Aβ1-42 bind more strongly to SUMO-2 than to ubiquitin, with binding driven by specific hydrogen bonds and hydrophobic interactions. SUMO-2 was found to inhibit the conversion of Aβ into β-sheet structures and impede Aβ aggregation. Notably, Aβ competes with SUMO-2 canonical substrates for binding, completely hindering SUMOylation reactions in vitro. Identifying SUMO-2/Aβ1-42 adducts in cellular extracts and live cells further highlights the biological significance of these interactions. Overall, the findings indicate that Aβ peptides impair SUMO-2 function, pointing to the necessity for more research on the implications of SUMOylation in Alzheimer's disease.