Figure 4.

SUMO-3 in human brain and its effect on APP processing in a human neuronal cell line. (A) SUMO-3 immunoreactivity in brain. ND, nondemented. Scale bars represent 20 and 100 μm for high and low magnifications, respectively. (B) Effect of SUMO-3 on Aβ, β-NTF, and α-NTF generation in SK-N-MC cells as determined by ELISA. (C) Schematic diagram summarizing effects of sumoylation on APP amyloidogenesis. Polysumoylation negatively (−) regulates but monosumoylation or undersumoylation positively (+) regulates Aβ production. SUMO proteins are indicated by small white circles.