The role of SUMOylation in regulating proteins that drive neuronal disease progression.

SUMOylation is a post-translational modification in which a Small Ubiquitin-like Modifier (SUMO) protein is reversibly attached to a lysine residue on a target protein in an ATP-dependent process. This modification can affect the function of target proteins by enhancing their stability or changing cellular translocation, thereby making SUMOylation a critical regulator in the pathogenesis of multiple diseases. The functional consequences of SUMOylation, however, are highly context dependent. In Alzheimer's disease, SUMOylation stabilizes proteins that drive disease progression and enhances neurotoxicity, thereby exacerbating these conditions. Similarly, in Progressive Supranuclear Palsy, SUMO-1 conjugation stabilizes truncated tau and blocks its ubiquitination, whereas SUMO-2/3 conjugation promotes Tau clearance and recovery from neuroinflammation, illustrating how distinct SUMO paralogues can exert opposing effects within the same disease. Conversely, increased SUMOylation can be neuroprotective in cerebral ischemia and Parkinson's disease by promoting autophagic clearance of pathogenic proteins. Beyond alterations in protein stability, aberrant SUMOylation can also lead to mis-localization of target proteins, which has been identified as a pathogenic mechanism in disorders such as Huntington's disease and Amyotrophic Lateral Sclerosis that results in impaired clearance and pathogenic buildup, which results in neuronal death. From a therapeutic standpoint, the SUMO inhibitor TAK-981 has shown promise in both Multiple Sclerosis and in pre-clinical glioblastoma models, underscoring the translational potential of targeting of this pathway. This review examines the multifaceted role of SUMOylation across diverse neurological conditions, evaluates the therapeutic potential of SUMO inhibitors and activators, and highlights the opportunities and challenges of modulating this pathway in currently incurable neurological disorders.