title: Positive and negative regulation of APP amyloidogenesis by sumoylation.
abstract: Amyloid beta peptide (Abeta) generated from amyloid precursor protein (APP) is central to Alzheimer's disease (AD). Signaling pathways affecting APP amyloidogenesis play critical roles in AD pathogenesis and can be exploited for therapeutic intervention. Here, we show that sumoylation, covalent modification of cellular proteins by small ubiquitin-like modifier (SUMO) proteins, regulates Abeta generation. Increased protein sumoylation resulting from overexpression of SUMO-3 dramatically reduces Abeta production. Conversely, reducing endogenous protein sumoylation with dominant-negative SUMO-3 mutants significantly increases Abeta production. We also show that mutant SUMO-3, K11R, which can only be monomerically conjugated to target proteins, has an opposite effect on Abeta generation to that by SUMO-3, which can form polymeric chains on target proteins. In addition, SUMO-3 immunoreactivity is predominantly detected in neurons in brains from AD, Down's syndrome, and nondemented humans. Therefore, polysumoylation reduces whereas monosumoylation or undersumoylation enhances Abeta generation. These findings provide a regulatory mechanism in APP amyloidogenesis and suggest that components in the sumoylation pathway may be critical in AD onset or progression.
authors.affiliation: Scios, Inc., 820 West Maude Avenue, Sunnyvale, CA 94085, USA.
authors.forename: Yonghong
authors.initials: Y
authors.lastname: Li
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.forename: Su
authors.initials: S
authors.lastname: Wang
authors.forename: Diana
authors.initials: D
authors.lastname: Quon
authors.forename: Yu-Wang
authors.initials: YW
authors.lastname: Liu
authors.forename: Barbara
authors.initials: B
authors.lastname: Cordell
mesh_terms: D016229:Amyloid beta-Peptides / Q000502:physiology*; D001921:Brain / Q000196:embryology / Q000502:physiology; D002460:Cell Line; D005333:Fetus; D005822:Genetic Vectors; D006801:Humans; D007668:Kidney; D007700:Kinetics; D000075687:NEDD8 Protein; D010957:Plasmids; D011499:Protein Processing, Post-Translational; D025842:SUMO-1 Protein / Q000235:genetics / Q000378:metabolism*; D025841:Small Ubiquitin-Related Modifier Proteins / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D014407:Tumor Cells, Cultured; D025801:Ubiquitin / Q000378:metabolism; D014452:Ubiquitins / Q000378:metabolism
chemical_list: D016229:Amyloid beta-Peptides; D000075687:NEDD8 Protein; C082860:NEDD8 protein, human; D025842:SUMO-1 Protein; C117909:SUMO2 protein, human; D025841:Small Ubiquitin-Related Modifier Proteins; D025801:Ubiquitin; D014452:Ubiquitins